Application of TGF-beta inhibitor in inducing formation of neural stem cells and organoids

文档序号：1871883 发布日期：2021-11-23 浏览：18次中文

阅读说明：本技术 TGF-β抑制剂在诱导神经干细胞及类器官形成中的应用 (Application of TGF-beta inhibitor in inducing formation of neural stem cells and organoids ) 是由魏君蔡萌周佳侯梦莹云轩于 2020-12-23 设计创作，主要内容包括：本发明提供了一种TGF-β小分子抑制剂在神经再生领域的新用途,可用于多种神经细胞及类脑器官的体外再生和定向分化。通过将其添加在一组化学成分明晰的基础培养基中,可以将多能干细胞诱导转变为多种神经干细胞来源的成体细胞,并且极大的提高了诱导得到的神经细胞数量及类器官大小。本发明提供的诱导系统拓展了单一小分子在外胚层细胞诱导分化领域里的崭新功能,同时避免了B27等代血清的使用,从而完全免除在细胞培养过程中动物源性成分的存在带来的潜在危险,大大拓展了多种神经细胞移植的临床前景。(The invention provides a new application of a TGF-beta small molecular inhibitor in the field of nerve regeneration, which can be used for in vitro regeneration and directional differentiation of various nerve cells and brain-like organs. By adding the cells into a group of basic culture media with clear chemical compositions, the pluripotent stem cells can be induced and converted into adult cells from various neural stem cells, and the number of the induced neural cells and the size of organoid are greatly improved. The induction system provided by the invention expands the brand-new function of a single small molecule in the field of ectodermal cell induction differentiation, and simultaneously avoids the use of B27 and other serum substitutes, thereby completely avoiding potential risks caused by the existence of animal-derived components in the cell culture process and greatly expanding the clinical prospect of transplantation of various nerve cells.)

1. Use of a TGF- β inhibitor for inducing neural stem cell and organoid formation, wherein the TGF- β inhibitor is 4- [2- (6-methylpyridin-2-yl) -5,6-dihydro-4H-pyrrolo [1,2-b ] pyrazol-3-yl ] quinoline-6-carboxamide.

2. The use according to claim 1, wherein the TGF- β inhibitor is added to a basal medium to constitute a neural stem cell induction medium.

3. The use according to claim 2, wherein the basal medium consists of Duchen modified eagle/F12 medium, minimal essential medium non-essential amino acids, sodium chloride, sodium selenite, insulin, and recombinant human transferrin.

4. The use according to claim 3, wherein the basal medium consists of Duchen modified eagle/F12 medium, 1% of the minimum essential medium non-essential amino acids, 0.1-0.8g/L sodium chloride, 13.6 μ g/L sodium selenite, 20ng/ml-42 μ g/ml insulin and 50-180ng/ml recombinant human transferrin.

5. The use according to claim 2, wherein the TGF- β inhibitor is present at a concentration of 10nM to 100 μ M.

6. The use according to claim 5, wherein the TGF- β inhibitor is present at a concentration of 12.5 μ M.

7. The use according to claim 6, wherein the basal medium comprises 0.5g/L sodium chloride, 13.6 μ g/L sodium selenite, 22ug/ml insulin and 100ng/ml recombinant human transferrin.

8. The use of claim 2, the neural stem cell formation comprising the steps of:

and (3) carrying out adherent culture on the pluripotent stem cells by adopting a neural stem cell induction culture medium.

9. The use of claim 8, wherein the pluripotent stem cells are mammalian pluripotent stem cells.

10. The use of claim 9, wherein the pluripotent stem cells are human pluripotent stem cells.

11. Use according to claim 8, wherein the adherent culture is performed in the presence of a basement membrane preparation.

12. The use of claim 11, wherein the base film formulation is a combination of one or more of a base glue, laminin and vitronectin.

13. The use according to claim 8, wherein said neural stem cells differentiate into neurons selected from one or more of the group consisting of: pain receptor neurons, photoreceptor neurons, dopaminergic neurons.

14. Use of neural stem cells obtained by the process of claim 8 for the preparation of a medicament for the treatment of nerve injury.

15. The use of claim 1, said organoid formation comprising the steps of:

(1) using the neural stem cell induction culture medium of claim 7, and adding 10 mu of MROCK inhibitor Y-27632 to perform pluripotent stem cell suspension cell mass culture;

(2) changing to the neural stem cell induction medium of claim 7 the next day, changing fresh medium every day until day 10;

(3) on day 10, the cells were replaced with the basal medium of claim 3 and cultured with 2% B27 cell culture supplement until day 120.

16. Use of the organoids obtained by the steps of claim 15 for drug screening for neurological diseases.

Technical Field

The invention belongs to the field of biology, and particularly relates to application of a TGF-beta small molecule inhibitor in inducing formation of neural stem cells and organoids.

Background

Ectoderm is the outermost layer formed during embryonic development, and as organogenesis begins, ectoderm cells gradually differentiate into important systems such as the brain, spinal cord, sensory organs, and the like. The nervous system is the important system responsible for thinking, emotion, perception, movement and other functions. Compared with diseases such as tumor, the quantity of drugs for nervous system diseases is small at present, and the development cycle is long, wherein the most important reason is the particularity of various primary cells in the ectodermal lineage, for example, the non-regenerability of primary neurons causes the scarcity of the in vitro drug screening platform for nervous system drugs.

In addition to being useful for drug screening, ectodermal cell regeneration in vitro can treat a variety of degenerative diseases, for example, neurodegenerative diseases are now common aging diseases, the treatment and care costs of the diseases are extremely expensive, and no specific drug is available on the market for effective treatment. Neurodegenerative diseases include Amyotrophic Lateral Sclerosis (ALS), Parkinson Disease (PD), Alzheimer Disease (AD), etc. The world health organization counts that in 2050, the number of patients with neurodegenerative diseases in China will exceed 3000 ten thousand, and the expected medical cost will exceed 1 trillion RMB. At present, medicaments are mainly used for supplementing or stimulating levodopa, nerve nucleus destruction or deep brain electrical stimulation operation and other treatment methods which are insufficient in brain, but the treatment methods cannot achieve good curative effect and bring adverse reactions which seriously affect the life quality, such as 'dyskinesia' or 'drug effect fluctuation'.

In addition to neurodegenerative diseases, Spinal Cord Injury (SCI) is a common traumatic disease of the nervous system, and the treatment and rehabilitation cost of SCI patients for a lifetime is more than 75 ten thousand dollars on average according to foreign statistics, and the cost of SCI patients in the united states exceeds 60 million dollars per year. The prevalence rate of China is higher than that of developed countries in Europe and America, expensive treatment cost is high, the huge influence on individuals and families caused by long-time rehabilitation and labor loss is caused, and the social burden is also caused.

The difficulty in the study of neurodegenerative diseases and spinal cord injury is that nerve cells of the central nervous system are not regenerative, and the scarcity of in vitro disease models is a limiting factor in basic research, and such diseases are caused by irreversible damage to the central nerve. The nerve cells include different nerve cell types such as nerve stem cells, mature neurons, astrocytes and oligodendrocytes. The existing nerve cell line has limited resources, is mostly a tumor cell line of the nervous system, and has unstable factors brought by EB virus in the line establishing process; because the in vitro passage of nerve cells is not easy, the nerve stem cells from embryo and fetus are not convenient to popularize due to ethical limitation. At present, although the allogeneic transplantation of the neural stem cells has achieved certain clinical effects, the above factors further hinder the clinical promotion of related diseases.

In 2006, the mountain middle-stretch team invented a "cocktail" method consisting of four transcription factors, OCT4, SOX2, KLF4 and c-Myc, which successfully reprogrammed terminally differentiated dermal fibroblasts into stem cells with differentiation pluripotency, called induced pluripotent stem cells (ipscs) (Takahashi K, et al., Cell,2006,126(4) pp.663-676; Takahashi K and Yamanaka S, Cell,2007,131(5) pp.861-872). These stem cells have a differentiation potential similar to that of embryonic stem cells (embryonic stem cells), and are capable of forming the three germ layers most essential for human development: ectoderm, mesoderm and endoderm, and eventually form a variety of adult cells. The invention breaks through the ethical limitation of using human embryonic stem cells in medicine, can solve the problem of immunological rejection in cell transplantation treatment, and greatly expands the application potential of stem cell technology in clinical medicine. The induction differentiation of ectoderm cells by using totipotent stem cells including embryonic stem cells and Induced Pluripotent Stem Cells (iPSCs) or pluripotent stem cells as raw materials can be used as a new idea of clinical treatment, and the application potential of the ectoderm cells in clinical medicine is greatly expanded.

Taking a nervous system as an example, in the field of regenerative medicine, at present, the induction of neural stem cells and neurons mostly adopts a Dual SMAD inhibition method (Chambers SM, et al., Nat Biotechnol,2009,27(3):275-80), and the neural stem cells obtained by the method can be differentiated into other types of neuronal cells, and the principle is to simulate a signal pathway in the early embryonic development by inhibiting BMP and TGF-beta pathways, so as to induce the generation of the neural stem cells. LDN-193189 and SB431542 are two widely used chemical small molecule inhibitors, which act on ALK2 and ALK3 in BMP4 pathway and ALK5 in TGF-beta pathway to achieve the formation of transplantation endoderm and mesoderm, thereby inducing ectoderm development and neurogenesis. In this way, induced nerve cells can be obtained in the presence of a serous component (Knockout Serum Replacement) (Chambers SM, et al., Nat Biotechnol.,2013,30(7): 715-. However, the nerve cells obtained by the double inhibition of the SMAD pathway (Dual SMAD inhibition) are often mixed with other incompletely differentiated cell types, which are caused by asynchronous cell differentiation, and the existence of such cells affects the effect of transplantation therapy at a certain level and brings safety concerns. Therefore, how to obtain high-purity differentiated cells is a technical problem which needs to be solved urgently in cell transplantation.

The standard chemical designation for the gallunertib used in the present invention (LY2157299) is 4- (2- (6-methylpyridin-2-yl) -5,6-dihydro-4H-pyrrolo [1,2-b ] pyrazol-3-yl) quinoline-6-carboxamide (4- (2- (6-methylpyridin-2-yl) -5, 6-dihydro-4H-pyrido [1,2-b ] pyrazol-3-yl) quinoline-6-carboxamide); other chemical names 2- (6-Methyl-pyridin-2-yl) -3- (6-Carbamoyl-quinolin-4-yl) -5,6-dihydro-4H-pyrrolo [1,2-b ] pyrazole (2- (6-Methyl-pyridin-2-yl) -3- (6-carboxymethyl-quinolin-4-yl) -5, 6-dihydro-4H-pyrolo [1,2-b ] pyrazole); or 4- [5,6-Dihydro-2- (6-methyl-2-pyridyl) -4H-pyrrolo [1,2-b ] pyrazol-3-yl ] -6-quinolinecarboxamide (4- [5,6-Dihydro-2- (6-methyl-2-pyridinyl) -4H-pyrido [1,2-b ] pyrazoyl-3-yl ] -6-quinolinecarboxamide); or LY-2157299, LY 2157299. Is a TGF-beta receptor I (TGF-beta RI, ALK5) small molecule inhibitor. LY2157299 is currently under phase II clinical assessment for anti-cancer activity against liver cancer and glioblastoma (Giannelli G1, Villa E, Lahn M. transforming Growth Factor- β as a Therapeutic Target in Hepatocellular cancer Res.2014Apr 1; 74(7):1890-4), inhibiting tumor Growth, invasion and metastasis processes by blocking TGF- β signaling pathway; in addition, several studies have shown that LY2157299 blocks CTGF production and inhibits neovascularization, thereby inhibiting the growth of cancer cells. At present, the development direction of the molecule is mainly based on the drug development and treatment of lung cancer, liver cancer and glioblastoma (pharmaceuticals.2020 May18; 12(5):459), and does not disclose any application in the nerve regeneration field.

The invention has the following advantages: compared with the currently internationally popular induction method of a plurality of small molecule combinations, the method not only greatly saves the production cost, but also shows great advantages of purity and yield. The invention also expands the brand new function of the small molecule in the ectoderm induction field. In addition, the invention avoids the use of B27 and other serum, thus completely avoiding the potential danger caused by the existence of animal-derived components in the process of cell culture, and greatly expanding the clinical prospect of nerve cell transplantation. The state among a plurality of batches is stable, the purity is high, and the problems of low purity and long period in the production process of cell medicines are solved; especially can be used for in vitro screening of nervous system disease drugs and treatment of neurodegenerative diseases, thereby having great economic and social effects.

Disclosure of Invention

In order to solve the defects of the prior art, the invention provides a serum-free culture medium for inducing neural stem cells and brain-like organs and a method for inducing differentiation.

In order to achieve the above purpose, the invention provides the following technical scheme:

the invention provides an application of a TGF-beta inhibitor in inducing formation of neural stem cells and organoids, wherein the TGF-beta inhibitor is 4- [2- (6-methylpyridin-2-yl) -5,6-dihydro-4H-pyrrolo [1,2-b ] pyrazol-3-yl ] quinoline-6-carboxamide.

Preferably, the TGF- β inhibitor is added to a basal medium to form a neural stem cell induction medium.

Preferably, the basic medium consists of Du's modified eagle/F12 medium, minimal essential medium non-essential amino acids, sodium chloride, sodium selenite, insulin and recombinant human transferrin.

Preferably, the basic medium consists of Du's modified eagle/F12 medium, 1% of minimum essential medium nonessential amino acids, 0.1-0.8g/L sodium chloride, 13.6. mu.g/L sodium selenite, 20-42. mu.g/ml insulin and 50-180ng/ml recombinant human transferrin.

More preferably, the above basal medium contains 0.5g/L sodium chloride, 13.6. mu.g/L sodium selenite, 22ug/ml insulin and 100ng/ml recombinant human transferrin.

Preferably, the concentration of the TGF-beta inhibitor is 10nM to 100. mu.M.

More preferably, the concentration of the TGF-beta inhibitor is 12.5. mu.M.

In one embodiment, inducing neural stem cell formation comprises the steps of: and (3) carrying out adherent culture on the pluripotent stem cells by adopting a neural stem cell induction culture medium.

Preferably, the pluripotent stem cells are mammalian pluripotent stem cells.

More preferably, the pluripotent stem cells are human pluripotent stem cells.

Preferably, adherent culture is performed in the presence of a basement membrane preparation.

More preferably, the above base film preparation is a combination of one or more of a base glue, laminin and vitronectin.

In one embodiment, the neural stem cell is differentiated into a neuron selected from one or more of the group consisting of: pain receptor neurons, photoreceptor neurons, dopaminergic neurons.

The invention also provides application of the neural stem cells obtained by the method in preparing a medicament for treating nerve injury.

In another embodiment, organoid formation comprises the steps of: (1) adding 10 mu M ROCK inhibitor Y-27632 into the neural stem cell induction culture medium to culture the pluripotent stem cell suspension cell mass; (2) changing the neural stem cell induction culture medium for the next day, and changing the culture medium every day until the 10 th day; (3) on day 10, the culture was changed to the basal medium, and 2% B27 cell culture supplement was added and cultured until day 120.

The invention also provides application of the organoid obtained by the method in screening of nervous system disease drugs.

The invention provides an application of an anti-tumor small molecule inhibitor in ectoderm in-vitro development, and relates to a combination of the compound and a basal culture medium, and culture and clinical application of the combination in various nerve cells.

The invention provides a preparation method of human induced neural stem cells, which comprises the following steps: the pluripotent stem cells are subjected to monolayer adherent culture in a serum-free sensory nerve induction medium, wherein the serum-free sensory nerve induction medium contains the chemical small molecules, amino acids, inorganic salts and other components used in the invention, but does not contain serum, BMP or substances of TGF signal transduction pathways and other components, and the neural stem cells forming a neural rosette uniform arrangement are obtained by adherent culture for 20 days.

In a particular embodiment, the substance acting on the BMP signal transduction pathway comprises one or more proteins, freely arranged and combined, of the following: BMP2, BMP4, BMP4, Smad1, Smad5, Smad 8; wherein the agent acting on the TGF transduction pathway comprises one or more proteins selected from the group consisting of: activin, TGF-beta, Nodal, Smad2, Smad 3.

In a specific embodiment, adherent culture is performed in the presence of a basal membrane preparation. The base membrane preparation can form a layer of thin membrane consisting of extracellular matrix molecules on the surface of a culture vessel, and can provide support similar to the in-vivo environment for the parameters of the morphology, growth, differentiation, movement and the like of cells. In a specific embodiment, the basement membrane is a combination of one or more of a substrate gel (stem cell Technologies), Laminin (Laminin), and vitronectin.

The serum-free medium in the present invention means that it does not contain serum isolated directly from blood. Serum is a clear liquid portion of plasma that is free of fibrinogen or blood cells and remains a liquid after blood coagulation. Serum-free media may contain serum substitutes, examples of which include purified substances such as serum albumin, transferrin, fatty acids, and the like.

In a particular embodiment, the adherent culture in steps 1 to 3 is preferably carried out in the presence of a basement membrane. The basement membrane can form a layer of membrane consisting of extracellular matrix molecules on the surface of a culture vessel, and can provide support similar to the in-vivo environment for the parameters of the morphology, growth, differentiation, movement and the like of cells. In a specific embodiment, the basement membrane is a combination of one or more of a substrate gel (stem cell Technologies), Laminin (Laminin), and vitronectin.

The serum-free medium in the present invention means that it does not contain serum isolated directly from blood. Serum is a clear liquid portion of plasma that is free of fibrinogen or blood cells and remains a liquid after blood coagulation. The serum-free medium may contain a serum substitute, and examples of the serum substitute include purified substances such as serum albumin, transferrin, fatty acids, and the like, which are well known in the art as substances that can substitute for serum.

Methods for preparing a medicament for treating nerve damage can be referred to published methods using embryonic stem cells as a medicament for treating nerve damage, such as Okada et al (Okada Y, Matsumoto A, Shimazaki T, Enoki R, Koizumi A, Ishii S, Itoyama Y, Sobue G, Okano H.Stem cells.2008vol.26, pp.3086-98).

The drug for treating nerve damage may contain, in addition to human-derived pluripotent cells, other components such as a buffer containing salts and/or antibiotics, and a nerve tissue (e.g., central nervous system or peripheral nervous system such as brain, spinal cord, etc.) as a treatment target. In addition, the target disease for treatment is not limited to any particular symptom, and includes traumatic diseases such as traumatic diseases (e.g., spinal cord injury), neurodegenerative diseases (e.g., amyotrophic lateral sclerosis, parkinson's disease, alzheimer's disease, progressive supranuclear palsy, huntington's disease, multiple system atrophy, and spinocerebellar degeneration), nerve cell necrosis caused by cerebral infarction and cerebral hemorrhage, and the like; and is not limited to any particular etiology, including primary causes associated with injury, cerebral infarction, etc., and secondary causes such as infection, tumor, etc., as long as they are diseases or pathological symptoms in which nerve cells are damaged.

Definition of

Neural Stem Cells (NSCs):

neural stem cells, which are cell populations that have the ability to differentiate into neurons, astrocytes and oligodendrocytes, are self-renewing, and are sufficient to provide a large number of brain tissue cells, are a class of progenitor cells that have the potential to divide and self-renew, and can generate a diverse range of cells of neural tissue, including neurons, oligodendrocytes and astrocytes, by a non-equal division pattern. According to the present invention, the neural stem cell may be an Induced Neural Stem Cell (iNSC). Nerval ring (rosette):

the formation of nerve embryos as an early neurogenesis process is considered to be a key stage in human embryonic development, and the nerve embryos develop into the brain, spinal cord and other nervous systems under the precise regulation of various factors. Neuroembryo formation is described as the generation of a rosette-like neural stem cell structure within a mass of cell tissue, i.e., a neural rosette structure characterizes a neuroembryo.

Advantageous effects

(1) The culture medium provided by the invention does not contain serum, solves the problem that the animal-derived culture method restricts the clinical use of stem cells, and is suitable for culturing neural stem cells including but not limited to induced pluripotent stem cells.

(2) The culture medium provided by the invention has the characteristics of simplicity, convenience, safety and high efficiency, and the directed differentiation of the stem cells into the neural stem cells is realized by using a single small molecule inhibitor.

(3) The neural stem cells induced and differentiated by the method provided by the invention have the capacity of differentiating into neurons and organoids, can be used as a material for clinical research and clinical treatment, can also be used for screening and researching medicines for nervous system diseases, and have huge economic and social effects.

Drawings

FIG. 1: the difference between the method of the present invention (LY induction method) and the control method (LSB induction method) during induction of neural stem cells was compared. FIG. 1a shows neural rosette structures generated by induction (LSB induction method) using various small molecule inhibitors; FIG. 1b shows the neural rosette structure generated by neural stem cell induction (LY induction method) using LY2157299 alone; FIG. 1c shows the difference in the number of cells obtained from neural stem cells obtained by the two methods.

FIG. 2: the screening result of the core components of the basic culture medium in the method of the invention. FIG. 2a shows the effect of different concentrations of sodium chloride on the osmotic pressure of the culture system, too high a concentration resulting in an osmotic pressure exceeding the tolerance of the cells; FIG. 2b shows the effect of different concentrations of insulin on cell growth (Cyquant experiment), the insulin concentration being positively correlated with cell viability; FIG. 2c shows the effect of different concentrations of recombinant human serum albumin on cell growth (Cyquant assay), the recombinant human serum albumin concentration being positively correlated to cell viability.

FIG. 3: molecular characterization of cells obtained by the method of the invention (LY induction method) and the control method (LSB induction method). FIG. 3a shows the structure of neural rosettes reconstructed after in vitro passage using neural stem cells obtained by the LSB induction method; FIG. 3b shows neural stem cells obtained using the LSB induction method, expressing the specific marker PAX 6; FIG. 3c shows neural stem cells obtained using the LSB induction method, expressing the specific marker Nestin; FIG. 3d shows the channel integration pictures of FIGS. 3a-3 c; FIG. 3e shows the structure of neural rosettes reconstructed after in vitro passages using neural stem cells obtained by the LY induction method; FIG. 3f neural stem cells obtained using LY induction method, expressing the specific marker PAX 6; FIG. 3g shows neural stem cells obtained using the LY induction method, expressing the specific marker Nestin; FIG. 3h shows the channel integration pictures of FIGS. 3e-3 g; FIGS. 3i-3k show the difference in expression of neural stem cell markers during neural stem cell formation using Q-PCR comparing the LY induction method with the LSB control induction method.

FIG. 4: different concentrations of LY2157299 were used for neural stem cell chemoinduction. FIG. 4a shows neural stem cells obtained using a multi-molecular control (LSB induction method, denoted CK); FIG. 4b shows chemical induction using 0nM LY 2157299; FIG. 4c shows chemical induction using 20nM LY 2157299; FIG. 4d shows chemical induction using 12.5. mu.M LY 2157299; FIG. 4e shows chemical induction using 25. mu.M LY 2157299; FIG. 4f is a graph comparing the regulation of Pax6 during induction using Q-PCR analysis at different concentrations of LY 2157299; FIG. 4g is a graph comparing the regulation of the apoptotic gene CASP3 during induction using Q-PCR analysis with different concentrations of LY 2157299.

FIG. 5: and (3) identifying the differentiation capability of the neural stem cells obtained by the LY induction method. FIGS. 5a-5c show pain receptor neurons from further differentiation of induced neural stem cells obtained by LY 2157299; fig. 5a shows a pain receptor neuron obtained by this method, expressing the pain receptor neuron specific marker SCN 11A; FIG. 5b shows the pain receptor neurons obtained by this method, expressing the pain receptor neuron specific marker Nestin; FIG. 5c shows the integration of two fluorescence channels of FIGS. 5a and 5 b; FIGS. 5d-5f show induced neural stem cells obtained by LY2157299, and further differentiated into dopaminergic neurons; FIG. 5d shows dopaminergic neurons obtained by this method, expressing the mature dopaminergic neuron specific marker Pitx 3; FIG. 5e shows dopaminergic neurons obtained by this method, expressing the mature dopaminergic neuron specific marker TH; FIG. 5f shows the integration of two fluorescence channels of FIGS. 5d and 5 e; FIGS. 5g-5i show photoreceptor neurons from further differentiation of induced neural stem cells obtained by LY 2157299; FIG. 5g shows photoreceptor neurons obtained by this method, expressing the photoreceptor neuron specific marker OPSIN; FIG. 5h shows photoreceptor neurons obtained by this method, expressing the photoreceptor neuron specific marker CRX; FIG. 5i shows the integration of two fluorescence channels of FIGS. 5g and 5 h.

FIG. 6: and analyzing the expression of MHC related genes of the neural stem cells obtained by the LY induction method. FIGS. 6a to 6d show that the neural stem cells obtained by LY2157299 were significantly lower in the expression of CD4, HLA-A, HLA-C, HLA-F and HLA-DPB1 than the human induced pluripotent stem cells, respectively.

FIG. 7: HLA-DR antigen of neural stem cells obtained by induction of LY2157299 was detected by flow cytometry. FIG. 7a is a negative control without antibody staining, and FIG. 7b is the result of HLA-DR detection of neural stem cells obtained by induction of LY 2157299. FIG. 7a-1 shows the use of both SSC and FSC channels to eliminate cell debris and other particulate impurities and thereby gate the cell population for analysis; FIGS. 7a-2 and 7a-3 show the analysis of cells using blank fluorescence channels and cell morphology, respectively; FIGS. 7a-4 show the analysis of cells using two blank fluorescence channels; FIG. 7b-1 shows the use of both SSC and FSC channels to eliminate cell debris and other particulate impurities and thereby gate the cell population for analysis; FIGS. 7b-2 and 7b-3 show the analysis of cells using CD45 PerCP (Abcam, cat # ab157309), HLA-DR FITC (CST, cat # 54126) channels, and cell morphology, respectively; FIGS. 7b-4 show the analysis of cells using two fluorescence channels CD45 PerCP, HLA-DR FITC. The results showed that LY2157299 induced expression of HLA-DR antigen of the obtained neural stem cells to be negative.

FIG. 8: LY2157299 can induce the production of brain-like organs. FIG. 8a shows a brain-like organ formed using the LSB induction method (D50); FIG. 8b shows a brain-like organ formed using LY induction method (D50); FIG. 8c shows a comparison of the number of spontaneous discharges of brain-like organs prepared by different methods using a multi-channel electrode system; FIG. 8d shows a comparison of spontaneous discharge frequencies of brain-like organs prepared by different methods using a multi-channel electrode system; figure 8e shows the diameter size of the brain-like organ prepared by the different methods (n-10); FIGS. 8f-8g show the differences in gene expression obtained by different organoid preparation methods using Q-PCR analysis.

Detailed Description

The present invention will be further described with reference to the following embodiments and drawings, and the present invention is not limited to the following embodiments. It is also to be understood that the terminology used in the examples is for the purpose of describing particular embodiments only, and is not intended to limit the scope of the present invention. It is intended that all such alterations and advantages be included in the invention, which occur to those skilled in the art, be considered as within the spirit and scope of the inventive concept, and that all such modifications and advantages be considered as within the scope of the appended claims and any equivalents thereof. In the description and claims of the present invention, the singular forms "a", "an" and "the" include plural referents unless the context clearly dictates otherwise. The experimental procedures in the following examples, in which specific conditions are not specified, are all common knowledge and general knowledge of those skilled in the art, or conditions recommended by the manufacturer. All materials and reagents used in the examples are commercially available products unless otherwise specified.

Example 1: preparation of neural stem cell induction culture medium

Formula of nerve induction basic culture medium (hereinafter referred to as NouvNeu 001): duke's modified eagle/F12 Medium (DMEM/F12), 1% minimal Essential Medium Non-Essential Amino Acids (MEM Non-Essential Amino Acids, Minimum Essential Medium Non-Essential Amino Acids, Thermo Fisher, Cat. No.: 11140076), Sodium Chloride (0.5 g/L), Sodium selenite (Sodium selenite, 13.6. mu.g/L), insulin (22. mu.g/ml), recombinant human transferrin (100 ng/ml).

The neural stem cell induction medium used in the present invention is prepared by adding LY2157299(Selleck, S2230) at 55nM to 24. mu.M to NouvNeu001 basal medium, preferably at a final concentration of 300nM, 500nM, 700nM, 900nM, 1. mu.M, 2.5. mu.M, 5. mu.M, 7.5. mu.M, 10. mu.M, 12.5. mu.M, 15. mu.M, 17.5. mu.M, 20. mu.M or 22. mu.M, and most preferably at 12.5. mu.M. The above-mentioned medium is abbreviated as LY induction medium, and the following group of experiments using this medium is referred to as LY induction method.

The control experiment used media prepared by adding 100nM LDN-193189(Selleck, S2618) and 10. mu.M SB431542(Selleck, S1067) to NouvNeu001 basal media. The above-mentioned medium is abbreviated as LSB induction medium, and the experimental group using this medium is hereinafter referred to as LSB induction method.

Example 2: induction and identification of neural stem cells

2.1 chemical induction of neural stem cells:

human pluripotent stem cells include embryonic pluripotent stem cells such as the H9 cell line and human induced pluripotent stem cells. Among them, the human induced pluripotent stem cells used in the present invention were cultured in a CD34 medium and a method for culturing the human induced pluripotent stem cells (method in ZL201910050800.7 patent)⁺And (4) reprogramming the cells.

Human pluripotent stem cells T25 cell culture flasks were coated with matrigel (STEMCELL technologies), plated, and incubated in a 37 ℃ incubator for more than one hour. According to 1 × 10⁶Cells were seeded in T25 flasks for expansion and passaging.

When performing nerve induction, coating 6-well culture plate with 50 μ g/ml polylysine (SIGMA, Cat: P6407), laying plate, and incubating in 37 deg.C incubator for more than 3 hr; then, the cells were further coated with 5. mu.g/ml Laminin (Lamin, SIGMAALDRICH, cat # I2020), plated, and incubated in an incubator at 37 ℃ for 3 hours or more. When the pluripotent stem cells reached 70% coverage, they were digested with EDTA at 37 ℃ for 5 minutes, and cell digestion was stopped with DMEM. After washing and centrifuging the cells, the ratio of the cells to the total volume of the cells is 2X 10⁵The ratio of each flask was re-inoculated in a T25 plate. The culture medium and the nerve induction compound are combined for nerve induction, and the culture medium is changed every day until the rosette of the neural stem cell is formed. Book (I)The results of the small and uniform neural rosette structure formed by the single molecule induction method (LY induction method) and the control of the multiple molecule induction method (LSB induction method) used in the present invention are shown in FIGS. 1a and 1b, which indicates that the single molecule induction method provided by the present invention produces more uniform induction results than the control using the multiple molecule induction method, but the rosette structure produced by the control experiment is not of the same size and has no neural rosette structure formed locally in the same culture period. Therefore, the single-molecule induction method provided by the method can more efficiently and uniformly induce the pluripotent stem cells to form the neural rosette structure.

2.2 identification of the concentration of key components in the Induction System:

quantitative cell viability assays were performed using the Cyquant assay to study the effect of LY2157299 on the physiological state of cells during long-term cell culture, using the LSB method as a control. A 96-well opaque cell culture plate was coated, cells were seeded according to 5X104 cell number per well after coating was completed, and the procedure of example 2.1 was repeated with three sets of replicates (the average of the three sets was calculated as data) at 37 ℃ with 5% carbon dioxide. Samples were taken on days 1, 5, 10, 15 and 20, respectively, and cell viability assays were performed using the CyQuant Kit (Invitrogen, cat # X12223) and data reads were performed using the SpectraMax i3 Multi-Mode Microplate Reader (VWR, model ID3-STD) according to the instructions. The results are shown in fig. 1c, and Cyquant experiment shows that LY2157299 induces more number of nerve cells compared to LSB method, indicating that LY2157299 has stronger proliferative activity during induction.

The Cyquant test is also used for quantitative detection of cell viability, so that the influence of recombinant insulin and recombinant serum albumin with different concentrations on the physiological state of cells in the long-term cell culture process is researched, the results are shown in fig. 2b and fig. 2c, the concentrations of the recombinant insulin and the recombinant serum albumin are positively correlated with the cell proliferation speed, and the ranges of the recombinant insulin and the recombinant serum albumin used in the invention belong to the optimal use range in combination with cost factors.

The influence of different concentrations of sodium chloride on the osmotic pressure of the culture system is detected by using a full-automatic freezing point osmometer (FM-8P, Shanghai medical instruments Co., Ltd.), and the specific operation is shown in a product instruction book (FM-8P, Shanghai medical instruments Co., Ltd.). The results of the experiment are shown in FIG. 2a, which shows a linear increase in the concentration of sodium chloride in relation to the osmotic pressure of the culture system. However, when the concentration reached 1g/ml, the osmotic pressure of the culture system had exceeded the cell culture limiting osmotic pressure by 320 mOsm/kg. The concentration of sodium chloride used in the present invention is the optimum concentration for cell culture.

2.3 fluorescent immune identification of markers of neural stem cells:

performing immunofluorescence staining identification on the neural stem cells obtained by the LY induction method and the LSB induction method respectively, fixing the cells for 40 minutes at room temperature by adopting 4% paraformaldehyde, and washing twice by using a DPBS buffer solution; permeabilizing with 0.1% Triton X-100 for 5 min, and washing twice with DPBS buffer; cells were then incubated overnight at 4 ℃ with DPBS buffer containing 10% horse serum and 0.1% Triton X-100; then adding a DPBS buffer solution to wash the cells, diluting the primary antibody with the DPBS buffer solution containing 2% of horse serum and 0.1% of Triton X-100, and incubating for 2 hours at 37 ℃; after washing the cells with DPBS buffer, the secondary antibodies were diluted with DPBS buffer containing 2% horse serum and 0.1% Triton X-100, incubated at 37 ℃ for 2 hours, washed three times, photographed and photographed using Leica DMi 8. The details of antibody use are shown in table 1, and the results are shown in fig. 3a to 3h, the LY induction method enables the pluripotent stem cells to produce neural rosette structures, and the cells express the neural stem cell markers Pax6 and Nestin, compared to the LSB induction method.

TABLE 1 antibodies used for cellular immunofluorescence staining

2.4 transcriptional level identification of neural stem cells:

Q-PCR was used to detect transcriptional changes of different marker genes during induction from pluripotent stem cells to neural stem cells. The induced pluripotent stem cells used in this example were obtained by LY induction and LSB induction, and total RNA extraction was performed using Rneasy Mini or Micro Kit (QIAGEN), and 1mg of RNA was synthesized into cDNA using SuperScript III First-Strand Synthesis System (Invitrogen). The labeling and reaction of Quantitative PCR were performed using SYBR Premix Ex Taq (TaKaRa) and Thermal Cycler Dice Real Time System (TaKaRa), and beta-Actin was used as an internal reference. All data were analyzed using delta-Ct method. Each set of experiments was performed using three replicates and variance statistics were performed. The primer sequences used to identify the genes encoding the different cellular markers are shown in table 2. As shown in fig. 3i-3k, the neural stem cells obtained by both the LY induction method and the LSB induction method expressed neural stem cell-specific markers Sox2, Pax6, and Nestin, and both the LY induction method increased the expression of the neural stem cell marker compared to the LSB induction method.

Concentration screening was performed by adding different concentrations of LY2157299 to novvneu 001 basal medium by the above method, and the results are shown in fig. 4b-4e, where fig. 4b shows that the absence of LY2157299 results in the inability of the cells to differentiate into ectodermal cells; FIG. 4c shows that chemical induction using 20nM LY2157299 resulted in a mixed cell population including neural cells; FIG. 4d shows that chemical induction using 12.5. mu.M LY2157299 resulted in a morphologically uniform cell population, and that the cells all had typical neural stem cell morphology, similar to the control (4 a); FIG. 4e shows that chemical induction using 25 μ M LY2157299 resulted in a mixed cell population of neural species, some cells formed longer axons and cells showed signs of intracellular vacuole stress. From the above results, it was found that differentiation was incomplete at low concentration, and that various types of cells were observed; neural stem cells obtained under high concentration conditions are easily differentiated and cell stress occurs. The transcript levels further demonstrated that the concentrations used in the present invention were optimal (FIGS. 4 f-4 g), and FIG. 4f shows that the concentration of LY2157299 was positively correlated with the amount of expression of Pax 6; FIG. 4g shows that LY2157299 concentration is positively correlated with apoptosis. The above results indicate that too low or too high a concentration of LY2157299 can adversely affect neural induction.

TABLE 2 primers for different marker genes during induction of pluripotent stem cells into neural stem cells

Example 3: differentiation function identification of neural stem cells

Neural stem cells obtained by the LY induction method of example 2 were subjected to directed differentiation in novnenu 001 basal medium. For neuronal differentiation, 6-well culture plates were coated with 50. mu.g/ml polylysine (SIGMA ALDRICH, cat # P6407), plated and incubated in a 37 ℃ incubator for 3 hours or more until cells were inoculated.

3.1 differentiation of nociceptor neurons:

neural stem cells obtained in example 2 were as follows 1X 10⁵The ratio of each flask was inoculated into a T25 flask, 3. mu.M CHIR99021(Selleck, cat # S2924), 10. mu.M SU5402(Tocris, cat # 3300/1), 10. mu.M DAPT (Selleck, cat # S2215) were added to NouvNeu001 basal medium, and fresh medium was changed every 3 days until day 21. The culture conditions were 37 ℃ and 5% CO₂. The experimental results showed that the neural stem cells obtained in example 2 had axonal structures after differentiation and expressed the pain receptor neuron markers SCN11A and Nestin (fig. 5a-5 c). Specifically, fig. 5a shows the induced neural stem cells obtained by LY2157299, further differentiated pain receptor neurons expressing the pain receptor neuron specific marker SCN 11A; FIG. 5b shows the pain receptor neurons obtained by this method, expressing the pain receptor neuron specific marker Nestin; FIG. 5c shows an integrated image of the two fluorescence channels of FIGS. 5a and 5 b.

3.2 Induction of dopamine neuronal cells:

the neural stem cells obtained in example 2 were measured at 1X 10⁵The ratio of each flask was re-inoculated in a T25 plate. 1 μ M Purmorphamine (Sellek, cat # S304) was added using NouvNeu001 basal medium2) And 1ng/ml TGF-beta 3(Novoprotein, cat # CJ44) under the conditions of 37 ℃ and 5% CO₂Fresh medium was changed every 3 days until neuron formation on day 30. The experimental results show that the neural stem cells obtained in example 2 have axonal structure after differentiation, and express the mature dopaminergic neuron specific markers Tyrosine Hydroxylase (TH) and Pitx3 (fig. 5d-5 f). Specifically, fig. 5d shows that dopaminergic neurons obtained by further differentiation of the induced neural stem cells obtained by LY2157299 express the mature dopaminergic neuron specific marker Pitx 3; FIG. 5e shows dopaminergic neurons obtained by this method, expressing the mature dopaminergic neuron specific marker TH; FIG. 5f shows an integrated image of the two fluorescence channels of FIG. 5d and FIG. 5 e.

3.3 photoreceptor neuron differentiation:

the neural stem cells obtained in example 2 were measured at 1X 10⁵The ratio of each flask was re-inoculated in a T25 plate. NouvNeu001 basal medium was used to add 0.5. mu.M Retinyl acetate (Retinyl acetate, SIGMA ALDRICH, cat # R7882) and fresh medium was changed every 3 days until day 21. The culture conditions were 37 ℃ and 5% CO₂. The experimental results showed that the neural stem cells obtained in example 2 had axonal structure after differentiation and expressed the photoreceptor neuronal markers OPSIN and CRX (FIGS. 5g-5 i). Specifically, FIG. 5g shows photoreceptor neurons obtained by further differentiation of induced neural stem cells obtained by LY2157299 expressing the photoreceptor neuron specific marker OPSIN; FIG. 5h shows photoreceptor neurons obtained by this method, expressing a photoreceptor neuron specific marker CRX; FIG. 5i shows an integrated picture of the two fluorescence channels of FIG. 5g and FIG. 5 h.

After the induction differentiation is completed, collecting cells for immunofluorescence staining identification: fixing the cells with 4% paraformaldehyde at room temperature for 40 minutes, and washing twice with DPBS buffer solution; then permeabilizing with 0.1% Triton X-100 for 5 minutes, and washing twice with DPBS buffer solution; cells were then incubated overnight at 4 ℃ with DPBS buffer containing 10% horse serum and 0.1% Triton X-100; after washing the cells with DPBS buffer, the secondary antibodies were diluted with DPBS buffer containing 2% horse serum and 0.1% Triton X-100, incubated at 37 ℃ for 2 hours, washed three times and photographed with Leica Dmi 8. Details of antibody use are shown in table 3.

TABLE 3 antibodies used for directed differentiation immunofluorescence staining

The above results indicate that the neural stem cells obtained by the LY induction method have the differentiation ability of various neurons.

Example 4: effect of LY2157299 on MHC formation

4.1Q-PCR assay:

major Histocompatibility Complex (MHC) genes of neural stem cells obtained by induction using LY2157299 were detected using the Q-PCR method according to the method of example 2.4, using pluripotent stem cells (iPS) as a control. The primer sequences are shown in Table 4, and the detection results are shown in FIG. 6, compared with the human pluripotent stem cells, the expression of MHC-associated genes CD4, HLA-A, HLA-C, HLA-F and HLA-DPB1 in the neural stem cells obtained by LY2157299 is extremely low.

TABLE 4 primers for immune system-related genes

4.2 flow cytometry detection:

HLA-DR antigen of neural stem cells obtained by induction of LY2157299 was detected by flow cytometry. HLA-DR is an MHC class II molecule that expresses work of antigen presentation to cellsCan be of critical importance and plays a key role in adoptive immune responses. The induced neural stem cells obtained in example 2 were digested with EDTA, washed with DPBS, centrifuged to remove the supernatant, and then 10 was added⁶The individual cells were resuspended in 100. mu.l of diluted primary antibody (CD45 PerCP, Abcam, cat # ab 157309; HLA-DR FITC, CST, cat # 54126), incubated on ice for 1 hour in the absence of light, the supernatant was removed by centrifugation, the cells were resuspended in 500. mu.l of antibody dilution buffer (CST) and analyzed on a flow cytometer. The control was incubated with no primary antibody. The results are shown in FIG. 7, in which FIG. 7a is a negative control and FIG. 7b is the result of HLA-DR detection of the neural stem cell obtained by LY2157299 induction, and show that the neural stem cell obtained by the LY induction method does not express HLA-DR. This result is in agreement with the results of example 4.1.

Example 5: effect of LY2157299 on organoid formation

The brain-like organ culture is carried out by adopting human induced pluripotent stem cells, and the formula of the brain-like organ induction culture medium is as follows: NouvNeu basal medium was supplemented with 12.5. mu.M LY 2157299. Induced pluripotent stem cells were digested into single cells using Accutase, and seeded into U-bottom-ultra-low adherence 96 well plates at a ratio of 9000 cells per well per 150ml brain-like induction medium. And 10. mu.M of ROCK inhibitor Y-27632(Selleck, S1049) was added thereto, and the mixture was cultured at 37 ℃ for 24 hours in a 5% carbon dioxide cell incubator (Panasonic, model: MCO-18 AC). The next day, fresh organoid induction medium without Y-27632 was changed until day 10. On day 10, the brain-like organs were transferred to an ultra-low-adherence 6-well plate, replaced with NouvNeu001 basal medium, and added with 2% B27 cell culture additives, and were cultured by rotation at 80rpm on a horizontal rotator in a 5% carbon dioxide cell incubator at 37 ℃ until day 120.

The control experiments were carried out according to published methods (Clair B et al, Nat methods.2019, Nov; 16(11): 1169-: N2B27 minimal medium was supplemented with 10. mu.M SB-431542, 100nM LDN-193189, and 2. mu.M XAV-939. The rest of the operations are the same as above. This method is abbreviated as the N2B27 method in the present invention and the figure.

Pictures of organoids and brain organoids and diameter measurements were taken using Leica Dmi8 and the results are shown in fig. 8a, 8b and 8 e.

And detecting the cell spontaneous emission signals of the induced brain-like organ by using a multi-channel electrode. The brain-like organs induced for 120 days were digested with 10% trypsin/EDTA for 5-8 minutes at 37 deg.C, coated with 100ng/ml polylysine (Poly-L-lysine, Sigma-Aldrich, P4707) using a 96-well MEA-system multichannel electrode plate (AXION Biosystem, US), placed in a 5% carbon dioxide cell incubator (Panasonic, model: MCO-18AC) at 37 deg.C for 12 hours; the polylysine-coated MEA multichannel electrode plate is taken out, the polylysine is absorbed, the MEA multichannel electrode plate is washed for 3 times by using sterile water, a PBS solution containing 3 mug/ml gelatin (Laminin, SIGMA ALDRICH, product number: I2020) is used as a nerve cell coating substrate, the nerve cell coating substrate is added into the MEA multichannel electrode plate, and the MEA multichannel electrode plate is placed in a 5% carbon dioxide cell incubator at 37 ℃ for coating for 3 hours. After the MEA multi-channel electrode plate is coated, the thickness of the MEA multi-channel electrode plate is 5 multiplied by 10⁵The number of each cell per well was seeded with the digested brain-like organ mixed cells. And placing the inoculated MEA multichannel electrode plate in an MEA chamber, adjusting the cell culture condition to 37 ℃ in Axis Navigator 2.0.2 software, and operating for 10 minutes until the chamber environment is stable, wherein the cell culture condition is 5% carbon dioxide. The cell self-emission signals were recorded using the Axis Navigator 2.0.2 software (AXION Biosystem, US). The experimental results show that the neurons induced by the NouNeu system exhibit good electrophysiological activity, and when the spontaneous cell discharge is detected by using the multichannel motor system, the LY induction method has more active electrophysiological activity compared with the N2B27 control induction method by comparing the cell discharge number per unit time (FIG. 8c) and the average discharge rate (FIG. 8 d).

Transcriptional changes of different marker genes following organogenesis were detected using Q-PCR: 120-day brain-like organs obtained by different culture methods and total RNA of human induced pluripotent stem cell control were extracted using Rneasy Mini or Micro Kit (QIAGEN), and 1mg of RNA was synthesized into cDNA using SuperScript III First-Strand Synthesis System (Invitrogen). The labeling and reaction of the Quan-reactive PCR were carried out using SYBR Premix Ex Taq (TaKaRa) and Thermal Cycler Dice Real Time System (TaKaRa), and Beta-actin was used as an internal reference. All data were analyzed using delta-Ct method. Each set of experiments was performed using three replicates and variance statistics were performed. The primer sequences used to identify the genes encoding the different cellular markers are shown in table 5. Both the LY induction method and the N2B27 control induction method resulted in the formation of brain-like organs that were able to produce glial cells, neural progenitor cells and neurons (FIGS. 8f-8 g).

TABLE 5 primers used in Q-PCR for brain-like organ detection

In conclusion, LY2157299 can induce the production of brain-like organs, and the brain-like organs have electrophysiological functions and the expression of key genes; in addition, the LY induction method resulted in brain-like organs with larger diameters and more active electrophysiological functions than the control N2B27 control induction method.

All documents referred to herein are incorporated by reference in their entirety. Furthermore, it should be understood that various changes and modifications can be made by those skilled in the art after reading the above teachings of the present invention, and such equivalent modifications also fall within the scope of the appended claims.

Sequence listing

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