Regulation of hematopoiesis and the hematopoietic stem cell niche by Wnt signaling pathways

Hematopoietic stem cells （HSCs） are a rare population of cells that are responsible for life-long generation of blood cells of all lineages. In order to maintain their numbers, HSCs must establish a balance between the opposing cell fates of self-renewal （in which the ability to function as HSCs is retained） and initiation of hematopoietic differentiation. Multiple signaling pathways have been implicated in the regulation of HSC cell fate. One such set of pathways are those activated by the Wnt family of ligands. Wnt signaling pathways play a crucial role during embryogenesis and deregulation of these pathways has been implicated in the formation of solid tumors. Wnt signaling also plays a role in the regulation of stem cells from multiple tissues, such as embryonic, epidermal, and intestinal stem cells. However, the function of Wnt signaling in HSC biology is still controversial. In this review, we will discuss the basic characteristics of the adult HSC and its regulatory microenvironment, the ＂niche＂, focusing on the regulation of the HSC and its niche by the Wnt signaling pathways.

Comprehensive regulation of traditional Chinese medicine on proliferation and differentiation of neural stem cells

Since the diccovery of neural stem cells(NSCs)in the embryonic and adult mammalian central nerous system,it provided novel ideas forneurogenesis as the potential of proliferation and differentiation of NSCs.One of the ways to promote the clinical application of neural stem cells(NSCs)is searching effective methods which regulate the proliferation and differentiation.This is also a problem urgently to be solved in medical field.Plenty of earlier studies have shown that traditional chinese medicine can promote the proliferation and differentiation of NSCs by regulating the related signaling pathway in vivo and in vitro.The reports of Chinese and foreign literatures on regulating the proliferation and differentiation of neural stem cells in recent ten years and their target and signaling pathways is analyzed in this review.The traditional chinese medicine regulate proliferation and differentiation of NSCs by the signaling pathways of Notch,PI3K/Akt,Wnt/β-catenin,and GFs.And,those signaling pathways have cross-talk in the regulation progress.Moreover,some traditional Chinese medicine,such as astragalus,has a variety of active ingredients to regulate proliferation and differentiation of NSCs through different signaling pathways.However,to accelerate the clinical application of neural stem cells,the studies aboutthe proliferation and differentiation of NSCs and Chinese medicine should be further deepened,the mechanism of multiple targets and the comprehensive regulation function of traditional Chinese medicine should be clarified.

Fetal bovine serum versus Chinese herbal formula Naoluoxintong serum supplementation for proliferation and differentiation of rat embryonic neural stem cells

BACKGROUND： How to induce endogenous neural stem cells （NSCs） to differentiate into needed neural cell types is a hot spot of current researches. OBJECTIVE： To compare differences between fetal bovine serum and Chinese herbal formula Naoluoxintong serum supplementation for inducing proliferation and differentiation in rat embryonic NSCs. DESIGN, TIME AND SETTING： An in vitro, serum pharmacology, comparative, observation study was performed from March to September in 2008 at the Laboratory of Neurodegenerative Diseases, College of Life Science in University of Science and Technology of China, the Key Laboratory Breeding Base of Acupuncture Foundation and Technology in Anhui University of Traditional Chinese Medicine, the Anhui Province Key Laboratory of R ＆ D of Chinese Medicine, and at the Level 3 Laboratory of Molecular Biology of the State Administration of Traditional Chinese Medicine. MATERIALS： The Chinese herbal formula Naoluoxintong was produced by Radix Astragali, Radix Notoginseng, Rhizoma Chuanxiong, Scolopendra at Anhui University of Traditional Chinese Medicine. Mouse anti-rat nestin, gliat fibrillary acidic protein, and galactocerebroside monoclonal antibodies, as well as rabbit anti-neuron-specific enolase polyclonal antibody were produced by Chemicon, Billerica, MA, USA. METHODS： Wistar rats aged 3 months were intragastrically infused with Naoluoxintong. Wistar rat embryonic NSCs （passage 8） were induced to proliferate and differentiate using 10% fetal bovine serum, 10% Naoluoxintong serum, and 10% rat serum. MAIN OUTCOME MEASURES： Phenotypic changes in cultured cells were detected using phase contrast microscopy, and cell proliferation and differentiation were observed using immunofluorescence staining. RESULTS： Proliferation and differentiation of embryonic NSCs was induced by three different types of blood serum. Although the differentiation time course with Nao/uoxintongserum was later than with the other two methods, the differentiated cells were morphologically similar to mature neurons to a greater extent. CONCLUSION： Nao/uoxintong serum supplementation induced differentiation of NSCs into neuronal-like cells and stimulated neuronal maturation.

Hematopoiesis reconstitution and anti-tumor effectiveness of Pai-Neng-Da capsule in acute leukemia patients with haploidentical hematopoietic stem cell transplantation

BACKGROUND With the rapid development of haploidentical hematopoietic stem cell transplantation(haplo-HSCT),primary poor graft function(PGF)has become a lifethreatening complication.Effective therapies for PGF are inconclusive.New Chinese patent medicine Pai-Neng-Da(PND)Capsule exerts dual effect in promoting hematopoiesis recovery and regulating immunity.Still,the application of PND capsule in hematopoietic stem cell transplantation,especially in the haplo-HSCT setting,has not yet been reported.AIM To evaluate the role of PND capsule in acute leukemia patients with haplo-HSCT.METHODS We retrospectively collected data of acute leukemia patients who underwent haplo-HSCT at the Affiliated People’s Hospital of Ningbo University between April 1,2015 and June 30,2020.Twenty-nine consecutive patients received oral PND capsule from the sixth day to the first month after haplo-HSCT were included in the PND group.In addition,31 patients who did not receive PND capsule during haplo-HSCT were included in the non-PND group.Subsequently,we compared the therapeutic efficacy according to the western medical evaluation indexes and Chinese medical symptom scores,and the survival between the PND group and the non-PND group,using the chi-square test,Fisher’s exact test,and the Kaplan-Meier method.RESULTS The duration of platelet engraftment was shorter in the PND group than in the non-PND group(P=0.039).The PND group received a lower frequency of red blood cells and platelet transfusions than the non-PND group(P=0.033 and P=0.035,respectively).In addition,PND capsule marginally reduced the rate of PGF(P=0.027)and relapse(P=0.043).After 33(range,4-106)months of follow-up,the 3-year relapse-free survival(P=0.046)and progression-free survival(P=0.049)were improved in the PND group than in the non-PND group.Also,the therapeutic efficacy of the PND group according to Chinese medical symptom scores was significantly better than that of the non-PND group(P=0.022).Moreover,the adverse events caused by PND capsule were mild.Nevertheless,there were no significant differences in the duration of neutrophil engraftment,the risk of infection within 100 days after haplo-HSCT,the acute graft-versus-host disease,or the 3-year overall survival between the two groups.CONCLUSION PND capsule could promote hematopoiesis reconstitution,improve the therapeutic efficacy of Chinese medical symptom scores,present anti-tumor effectiveness,and prolong the survival of acute leukemia patients with haplo-HSCT.

Preliminary Study on Biological Properties of Adult Human Bone Marrow-derived Mesenchymal Stem Cells

Objective： To establish a method of culture and expansion of adult human bone marrow-derived MSCs in vitro and to explore their biological properties. Methods： Mononuclear cells were obtained from 5 mL adult human bone marrow by density gradient centrifugation with Percoll solution. Adult human MSCs were cultured in Dulbecco＇s Modified Eagle＇s Medium with low glucose （LG-DMEM） containing 10% fetal calf serum at a density of 2×10^5 cell/cm^2. The morphocytology was observed under phase-contrast microscope. The cell growth was measured by MTT method. The flow cytometer was performed to examine the expression of cell surface molecules and cell cycle. The ultrastructure of MSCs was observed under transmission electron microscope. The immunomodulatory functions of MSCs were measured by MTT method. The effects of MSCs on the growth of K562 cells and the dynamic change of HA, IV-C, LN concentration in the culture supernatant of MSCs was also observed. Results： The MSCs harvested in this study were homogenous population and exhibited a spindle-shaped fibroblastic morphology. The cell growth curve showed that MSCs had a strong ability of proliferation. The cells were positive for CD44, while negative for hematopoietic cell surface marker such as CD3, CD4, CD7, CD13, CD14, CD15, CD19, CD22, CD33, CD34, CD45 and HLA-DR, which was closely related to graft versus host disease. Above 90% cells of MSCs were found at G0/G1 phase. The ultrastructure of MSCs indicated that there were plenty of cytoplasmic organelles. Allogeneic peripheral blood lymphocytes proliferation was suppressed by MSCs and the inhibition ratio was 60.68% （P〈0.01）. The suppressive effect was also existed in the culture supernatant of MSCs and the inhibition ratio was 9.00% （P〈0.05）. When lymphocytes were stimulated by PHA, the suppression effects of the culture supernatant were even stronger and the inhibition ratio was 20.91% （P〈0.01）. Compared with the cell growth curve of the K562 ceils alone, the K562 ceils cocultured with MSCs grew slowly and the exponential phase of growth wasn＇t significant. Seeing from the concentration curve, as time passed, the concentration of HA increased quickly, while those of IV-C and LN didn＇t change much. Conclusion： The method for culture and expansion of adult human bone marrow-derived MSCs in vitro has been successfully established in this study. MSCs were a homogenous population that had unique growth phenotype and multilineage potential. Preliminary study proved that it had the abilities of immunomodulatory function, antitumor, hematopoietic supporting and could act as seed cell of tissue engineering.

Effects of Ginkgo biloba extract EGb761 on neural differentiation of stem cells offer new hope for neurological disease treatment

Stem cell transplantation has brought new hope for the treatment of neurological diseases.The key to stem cell therapy lies in inducing the specific differentiation of stem cells into nerve cells.Because the differentiation of stem cells in vitro and in vivo is affected by multiple factors,the final differentiation outcome is strongly associated with the microenvironment in which the stem cells are located.Accordingly,the optimal microenvironment for inducing stem cell differentiation is a hot topic.EGb761 is extracted from the leaves of the Ginkgo biloba tree.It is used worldwide and is becoming one of the focuses of stem cell research.Studies have shown that EGb761 can antagonize oxygen free radicals,stabilize cell membranes,promote neurogenesis and synaptogenesis,increase the level of brain-derived neurotrophic factors,and replicate the environment required during the differentiation of stem cells into nerve cells.This offers the possibility of using EGb761 to induce the differentiation of stem cells,facilitating stem cell transplantation.To provide a comprehensive reference for the future application of EGb761 in stem cell therapy,we reviewed studies investigating the influence of EGb761 on stem cells.These started with the composition and neuropharmacology of EGb761,and eventually led to the finding that EGb761 and some of its important components play important roles in the differentiation of stem cells and the protection of a beneficial microenvironment for stem cell transplantation.

A ginkgo biloba extract promotes proliferation of endogenous neural stem cells in vascular dementia rats

The ginkgo biloba extract EGb761 improves memory loss and cognitive impairments in patients with senile dementia. It also promotes proliferation of neural stem cells in the subventricular zone in Parkinson＇s disease model mice and in the hippocampal zone of young epileptic rats. However, it remains unclear whether EGb761 enhances proliferation of endogenous neural stem cells in the brain of rats with vascular dementia. In this study, a vascular dementia model was established by repeatedly clipping and reperfusing the bilateral common carotid arteries of rats in combination with an intraperitoneal injection of a sodium nitroprusside solution. Seven days after establishing the model, rats were intragastrically given EGb761 at 50 mg/kg per day. Learning and memory abilities were assessed using the Morris water maze and proliferation of endogenous neural stem cells in the subventricular zone and dentate gyrus were labeled by 5-bromo-2-deoxyuridine immunofluorescence in all rats at 15 days, and 1, 2, and 4 months after model establishment. The escape latencies in Morris water maze tests of rats with vascular dementia after EGb761 treatment were significantly shorter than the model group. Immunofluorescence staining showed that the number and proliferation of 5-bromo-2-deoxyuridine-positive cells in the subventricular zone and dentate gyrus of the EGb761-treated group were significantly higher than in the model group. These experimental findings suggest that EGb761 enhances proliferation of neural stem cells in the subventricular zone and dentate gyrus, and significantly improves learning and memory in rats with vascular dementia.

Combined acupuncture and HuangDiSan treatment affects behavior and synaptophysin levels in the hippocampus of senescence-accelerated mouse prone 8 after neural stem cell transplantation

Sanjiao acupuncture and HuangDiSan can promote the proliferation, migration and differentiation of exogenous neural stem cells in senescence-accelerated mouse prone 8 （SAMP8） mice and can improve learning and memory impairment and behavioral function in dementia-model mice. Thus, we sought to determine whether Sanjiao acupuncture and HuangDiSan can elevate the effect of neural stem cell transplantation in Alzheimer’s disease model mice. Sanjiao acupuncture was used to stimulate Danzhong （CV17）, Zhongwan （CV12）,Qihai （CV6）, bilateral Xuehai （SP10） and bilateral Zusanli （ST36） 15 days before and after implantation of neural stem cells （5 × 10^5） into the hippocampal dentate gyrus of SAMP8 mice. Simultaneously, 0.2 mL HuangDiSan, containing Rehmannia Root and Chinese Angelica,was intragastrically administered. Our results demonstrated that compared with mice undergoing neural stem cell transplantation alone,learning ability was significantly improved and synaptophysin mRNA and protein levels were greatly increased in the hippocampus of mice undergoing both Sanjiao acupuncture and intragastric administration of HuangDiSan. We conclude that the combination of Sanjiao acupuncture and HuangDiSan can effectively improve dementia symptoms in mice, and the mechanism of this action might be related to the regulation of synaptophysin expression.

Yin and Yang of mesenchymal stem cells and aplastic anemia

Acquired aplastic anemia(AA) is a bone marrow failure syndrome characterized by peripheral cytopenias and bone marrow hypoplasia. It is ultimately fatal without treatment, most commonly from infection or hemorrhage. Current treatments focus on suppressing immune-mediated destruction of bone marrow stem cells or replacing hematopoietic stem cells(HSCs) by transplantation. Our incomplete understanding of the pathogenesis of AA has limited development of targeted treatment options. Mesenchymal stem cells(MSCs) play a vital role in HSC proliferation; they also modulate immune responses and maintain an environment supportive of hematopoiesis. Some of the observed clinical manifestations of AA can be explained by mesenchymal dysfunction. MSC infusions have been shown to be safe and may offer new approaches for the treatment of this disorder. Indeed, infusions of MSCs may help suppress auto-reactive, T-cell mediated HSC destruction and help restore an environment that supports hematopoiesis. Small pilot studies using MSCs as monotherapy or as adjuncts to HSC transplantation have been attempted as treatments for AA. Here we review the current understanding of the pathogenesis of AA and the function of MSCs, and suggest that MSCs should be a target for further research and clinical trials in this disorder.

Effects of resveratrol on hydrogen peroxide-induced oxidative stress in embryonic neural stem cells

Resveratrol, a natural phenolic compound, has been shown to prevent cardiovascular diseases and cancer and exhibit neuroprotective effects. In this study, we examined the neuroprotective and antJoxJdant effects of resveratrol against hydrogen peroxide in embryonic neural stem cells. Hydrogen peroxide treatment alone increased catalase and glutathione peroxidase activities but did not change superoxide dismutase levels compared with hydrogen peroxide ＋ resveratrol treatment. Nitric oxide synthase activity and concomitant nitric oxide levels increased in response to hydrogen peroxide treatment. Conversely, resveratrol treatment decreased nitric oxide synthase activity and nitric oxide levels. Resveratrol also attenuated hydrogen peroxide-induced nuclear or mitochondrial DNA damage. We propose that resveratrol may be a promising agent for protecting embryonic neural stem cells because of its potential to decrease oxidative stress by inducing higher activity of antioxidant enzymes, decreasing nitric oxide production and nitric oxide synthase activity, and alleviating both nuclear and mitochondrial DNA damage.

Quantitative and qualitative in vitro analysis of the stem cell potential of hematopoietic cells purified from murine skeletal muscle

The murine skeletal muscle contains hematopoietic stem cells, but this potential has so far not been studied quantitatively or qualitatively in vitro. To quantify the hematopoietic stem cell potential, we have used highly purified SP/CD45^＋ cells in long-term culture initiating cell （LTC-IC） assays. The SP/CD45^＋ cell population purified from murine muscle was found to have significant stem cell activity with an LTC-IC frequency of 1/640. Single-cell-sorted SP/CD45^＋ cells from muscle exhibited robust proliferative activity in vitro at day 16 （380-fold amplification）, especially after culture with OP-9 layers that also support embryonic stem cells. Amplified cell populations originating from single cells exhibited multilineage differentiation ability with evidence of myeloid, lymphoid and NK cell markers. Thus, our results demonstrate that hematopoietic stem cells that can be quantified by LTC-IC assays exist in the murine skeletal muscle and show also for the first time, at the single-cell level, that these cells exhibit multilineage differentiation ability and major proliferative potential.

Zhichan decoction induces differentiation of dopaminergic neurons in Parkinson's disease rats after neural stem cell transplantation

The goal of this study was to increase the dopamine content and reduce dopaminergic metabolites in the brain of Parkinson’s disease rats. Using high-performance liquid chromatography, we found that dopamine and dopaminergic metabolite（dihydroxyphenylacetic acid and homovanillic acid） content in the midbrain of Parkinson’s disease rats was increased after neural stem cell transplantation ＋ Zhichan decoction, compared with neural stem cell transplantation alone. Our genetic algorithm results show that dihydroxyphenylacetic acid and homovanillic acid levels achieve global optimization. Neural stem cell transplantation ＋ Zhichan decoction increased dihydroxyphenylacetic acid levels up to 10-fold, while transplantation alone resulted in a 3-fold increment. Homovanillic acid levels showed no apparent change. Our experimental findings show that after neural stem cell transplantation in Parkinson’s disease rats, Zhichan decoction can promote differentiation of neural stem cells into dopaminergic neurons.

Neural stem cell proliferation and differentiation in a neonatal rat model of hypoxia/ischemia injury Acupuncture at Ren,Du,and urinary bladder meridians

BACKGROUND： Acupuncture improves the prognosis of neonatal hypoxic-ischemic encephalopathy （HIE）. However, the cytological mechanism of acupuncture therapy remains poorly understood. In situ neural stem cell （NSC） proliferation theory proposes that the proliferation and differentiation of NSCs plays an important role in HIE treatment with acupuncture. OBJECTIVE： To investigate NSC proliferation and differentiation in the brain of a rat model of HIE during acupuncture at Ren, Du, and urinary bladder meridians. DESIGN, TIME AND SEB＇ING： A randomized, controlled animal experiment was performed at the Central Laboratory of Shantou University Medical College from July 2005 to June 2009. MATERIALS： A 32# 1-cun stainless steel acupuncture needle was purchased from Suzhou Acupuncture Supplies Co. Ltd., China.METHODS： A total of 90 Sprague-Dawley rats, aged 7 days, were randomly assigned to acupuncture, model and normal groups, with 30 animals in each group. Animals in acupuncture and model groups were subjected to left common carotid artery ligation followed by hypoxia for 2 hours to establish neonatal HIE models. Acupuncture group rats underwent acupuncture at Ren, Du, and urinary bladder meridians, once a day. MAIN OUTCOME MEASURES： The number, appearance, and distribution of bromodeoxyuridine （BrdU）-positive cells in the cerebral cortex and hippocampus of each group were compared. In addition, NSC differentiation in the occipital cortex and hippocampal dentate gyrus 40 days following model establishment was detected.RESULTS： BrdU-positive cells were dispersed in the cerebral cortex and hippocampus. The number of BrdU-positive cells in occipital cortex and hippocampal dentate gyrus of HIE rats remained unchanged following 3 and 7 days of acupuncture, but a significant increase was detected on days 14 and 28 （P 〈 0.01 or P 〈 0.05）. At 40 days, immunofluorescence showed that a majority of BrdU-positive cells were co-lableled with the neuron marker, and neuron specific enolase, and a few were co-labeled with the astrocyte marker, and glial fibrillary acidic protein. CONCLUSION： Acupuncture at Ren, Du, and urinary bladder meridians promoted NSC proliferation in the occipital cortex and hippocampal dentate gyrus of HIE rats. Moreover, acupuncture-induced neoformative NSCs mostly differentiated into neurons.

Characterization of a mesenchymal stem cell line that differentiates to bone and provides niches supporting mouse and human hematopoietic stem cells

Identification of mouse cell lines with properties of primary multipotential mesenchymal stromal cells (MSC) is required to facilitate the use of mouse models for evaluation of mechanisms in bone formation, hematopoiesis and cellular therapies for regenerative medicine. Primary murine MSC vary between strains, are difficult to grow in vitro and have inconsistent properties. The main aim of the study was to establish OMA-AD cells as an appropriate model system to conduct studies on MSC, bone formation and hematopoiesis. OMA-AD cells were isolated by differential trypsinization of C57BL/6J mouse bone marrow (BM) cells. The cells were then repassaged, cloned and characterized. OMA-AD cells were immortal and non-tumorigenic, differentiated readily to all mesenchymal cell types including bone, supported mouse and human hematopoiesis and were immunosuppressive. Our results demonstrated that OMA-AD cells possessed the properties of primary MSC. In addition, these cells grew readily and consistently, thereby facilitating future studies of bone formation, hematopoiesis and mesenchymal cells for regenerative medicine.

Ocular manifestations and quality of life in patients after hematopoietic stem cell transplantation

AIM:To explore the relationship between ocular and systemic conditions and the impact of ocular complications on the quality of life(QOL)in patients after allogeneic hematopoietic stem cell transplantation(ALLO-HSCT).METHODS:Forty-four patients with severe hematopoietic disease were enrolled after ALLO-HSCT at our center from July 2018 to October 2020.They completed two questionnaires:the Ocular Surface Disease Index(OSDI)and the quality-of-life scale for Chinese patients with visual impairment(SQOL-DV1).Ocular conditions and systemic conditions were also assessed.RESULTS:Eye damage was correlated with total bilirubin(P=0.005),and gamma-glutamyl transferase(GGT)(P=0.021).There was no significant correlation between the overall QOL score and OSDI(P=0.8226)or SQOLDV1(P=0.9526)scores.The OSDI and the overall QOL score were not correlated with ocular conditions,including best-corrected visual acuity(BCVA),intraocular pressure,Schirmer tear test II,sodium fluorescein staining,tear film breakup time,and tear meniscus height.SQOLDV1 was correlated with BCVA(P=0.0007),sodium fluorescein staining(P=0.007),and tear film breakup time(P=0.0146).CONCLUSION:In some patients,early ocular symptoms are not evident after ALLO-HSCT,while ocular surface complications can be observed after a comprehensive ophthalmological examination.Especially for those with elevated total bilirubin or GGT,regular ophthalmic follow-up visits are essential to diagnose and treat ocular graft versus host disease(o GVHD),especially for patients with elevated total bilirubin or GGT.

Buyang Huanwu Decoction regulates neural stem cell behavior in ischemic brain

The traditional Chinese medicine Buyang Huanwu Decoction has been shown to improve the neu- rological function of patients with stroke. However, the precise mechanisms underlying its effect remain poorly understood. In this study, we established a rat model of cerebral ischemia by middle cerebral artery occlusion and intragastrically administered 5 g/kg Buyang Huanwu Decoction, once per day, for 1, 7, 14 and 28 days after cerebral ischemia. Immunohistochemical staining revealed a number of cells positive for the neural stem cell marker nestin in the cerebral cortex, the subven- tricular zone and the ipsilateral hippocampal dentate gyrus in rat models of cerebral ischemia. Buyang Huanwu Decoction significantly increased the number of cells positive for 5-bromodeoxyuridine （BrdU）, a cell proliferation-related marker, microtubule-associated protein-2, a marker of neuronal differentiation, and growth-associated protein 43, a marker of synaptic plasticity in the ischemic rat cerebral regions. The number of positive cells peaked at 14 and 28 days after intragastric administration of Buyang Huanwu Decoction. These findings suggest that Buyang Huanwu Decoction can promote the proliferation and differentiation of neural stem cells and en- hance synaptic plasticity in ischemic rat brain tissue.

Cocultivation of umbilical cord blood CD34^+ cells with retro-transduced hMSCs leads to effective amplification of long-term culture-initiating cells

AIM： To establish a novel coculture system for ex vivo expansion of umbilical cord blood（UCB） hematopoietic progenitors using thrombopoietin （TPO）/FIt-3 ligand （FL）-transduced human marrow-derived mesenchymal stem cells （tfhMSCs） as feeder. METHODS： UCB CD34^＋ cells were isolated and cultured using four culture systems in serum-containing or serumfree medium. Suitable aliquots of cultured cells were used to monitor cell production, clonogenic activity, and long-term culture-initiating culture （LTC-IC） output. Finally, the severe-combined immunodeficient （SCID） mouse-repopulating cell （SRC） assay was performed to confirm ability of the cultured cells to reconstitute longterm hematopoiesis. RESULTS： There were no significant differences in the number of total nudeated cells among different culture systems in serum-containing medium during 21-d culture. However, on d 14, the outputs of CD34^＋ cells, CFU-C and CFU-GEMM in tfhMSCs coculture system were significantly enhanced. LTC-IC assay demonstrated that the tfhMSCs coculture system had the most powerful activity. The severe-combined immunodeficient （SCID） mouse repopulating cell （SRC） assay confirmed extensive ability of the expanded cells to reconstitute long-term hematopoiesis. Furthermore, PCR analysis demonstrated the presence of human hematopoietic cells in the bone marrow and peripheral blood cells of NOD/SCID mice.CONCLUSION： The TPO/FL-transduced hMSCs, in combination with additive cytokines, can effectively expand hematopoietic progenitors from UCB in vitro and the tfhMSCs coculture system may be a suitable system for ex vivo manipulation of primitive progenitor cells under contact culture conditions.

Effects of Serum from Aplastic Anemia patients on the Expression of Cyclin D3 Isoform in Umbilical Cord Blood CD34^+ Cells

Summary: The pathogenesis of aplastic anemia (AA) was explored and the effects of AA serum on the expression of crucial cyclin D isoform (cyclin D3) in umbilical cord blood hematopoietic stem/progenitor cells were observed. The CD34+ cells were isolated from the cord blood with MIDI-MACS Semi-solid methylcellulose culture technique was used to measure the formation of CFU-GM; The expression level of cyclin D3 was assayed by semi-quantitative RT-PCR and Western-blot after the hematopoietic stem/progenitor cells were incubated in AA serum. The results showed that the AA serum could inhibit the formation of CFU-GM and down regulate the expression level of the cyclin D3 at the mRNA and protein level respectively. In conclusion, the AA serum could inhibit the proliferation of hematopoietic stem cells and down regulate level of cyclin D3, which might be one mechanism of hematopoiesis inhibition in AA.

不同干细胞来源外泌体及其携非编码RNA诊疗骨性关节炎

背景:外泌体可在骨性关节炎患者滑液和血浆中检测出来,其水平随着骨性关节炎的进展而不断变化,并且可以对骨性关节炎的局部炎症、软骨钙化和关节退化起缓解作用。目的:旨在全面了解不同干细胞来源外泌体在骨性关节炎诊疗中的作用和机制,并提出了外泌体治疗骨性关节炎的前景和挑战。方法:检索PubMed及中国知网数据库,英文检索词为“exosomes,osteoarthritis,mesenchymal stem cells,stem cells”,中文检索词为“外泌体,骨性关节炎,间充质干细胞,干细胞”,对2003年10月至2023年10月发表的文献进行检索,最终纳入99篇文献进行综述。结果与结论:外泌体的出现给骨性关节炎的诊断和治疗带来了希望。外泌体内含RNA、蛋白质及脂类的差异能够作为骨性关节炎的生物标志物用于诊断。同时,来自不同干细胞的外泌体均能够有效保护软骨细胞、缓解炎症、维持软骨基质代谢以及调节血管生成和软骨下骨重塑,表现出治疗骨性关节炎的优秀潜力。工程化外泌体则突破传统局限,通过调节特定非编码RNA表达增强治疗特异性与效率,为骨性关节炎的治疗提供新策略。

NLRP3炎性小体在脊髓损伤后小胶质细胞中的作用

背景:NOD样受体热蛋白结构域相关蛋白3(NOD-like receptor thermal protein domain associated protein 3,NLRP3)炎性小体与脊髓损伤后的神经炎症密切相关,小胶质细胞极化和焦亡在其中发挥关键作用,靶向调控NLRP3有利于诱导小胶质细胞从M1促炎表型向M2抗炎表型极化和调节小胶质细胞焦亡,是一个有前景的治疗策略。目的:归纳NLRP3炎性小体在脊髓损伤后小胶质细胞中作用的分子机制以及治疗策略的研究进展。方法:检索PubMed、Web of Science和中国知网数据库,英文检索词为“spinal cord injury,NLRP3,microglia,polarization,pyroptosis”,中文检索词为“脊髓损伤,NLRP3,小胶质细胞,极化,焦亡,炎症”,按纳入和排除标准共纳入79篇文献进行总结。结果与结论:①目前,关于脊髓损伤复杂的发病机制尚未有统一定论,大量研究表明脊髓损伤与炎症因子和信号通路关系密切,以NLRP3炎性小体作为其发病机制和治疗突破口的相关研究也是当前的热点。②NLRP3炎性小体在脊髓损伤后的炎症反应、氧化应激和神经元恢复等起到关键作用。③小胶质细胞是脑和脊髓中的免疫细胞,是继发性脊髓损伤最重要的调节因子,脊髓损伤后小胶质细胞对内部环境作出调整,主要表现为极化及焦亡,产生大量炎症因子,阻碍脊髓损伤的神经再生和功能恢复,通过调控小胶质细胞表型变化,是治疗脊髓损伤的另一个关键因素。④NLRP3炎性小体与小胶质细胞密切相关,脊髓损伤后NLRP3炎性小体主要在小胶质细胞中表达,其会促进小胶质细胞向M1极化和促进促裂解蛋白D的产生,进一步破坏神经稳态,从而加重脊髓损伤的进展。⑤许多分子参与NLRP3炎性小体调控小胶质细胞,其中核转录因子κB及MAPK信号通路促进NLRP3炎性小体表达,其他信号通路抑制该炎性小体表达。⑥目前有大量的外源性分子及药物调控NLRP3炎性小体,临床应用前景广泛,已有相关药物处于临床试验阶段并取得良好疗效,如NLRP3特异性抑制剂MCC950,但如何精准控制靶向递送、减少对其他组织器官影响等关键问题亟需解决,随着研究的深入,未来有望在脊髓损伤治疗方式上作出新的突破。