Influence of hypoxia on retinal progenitor and ganglion cells in human induced pluripotent stem cell-derived retinal organoids

AIM:To observe the effect of low oxygen concentration on the neural retina in human induced pluripotent stem cell(hiPSC)-derived retinal organoids(ROs).METHODS:The hiPSC and a three-dimensional culture method were used for the experiments.Generated embryoid bodies(EBs)were randomly and equally divided into hypoxic and normoxic groups.Photographs of the EBs were taken on days 38,45,and 52,and the corresponding volume of EBs was calculated.Simultaneously,samples were collected at these three timepoints,followed by fixation,sectioning,and immunofluorescence.RESULTS:The proportion of Ki67-positive proliferating cells increased steadily on day 38;this proliferationpromoting effect tended to increase tissue density rather than tissue volume.On days 45 and 52,the two groups had relatively similar ratios of Ki67-positive cells.Further immunofluorescence analysis showed that the ratio of SOX2-positive cells significantly increased within the neural retina on day 52(P<0.05).In contrast,the percentage of PAX6-and CHX10-positive cells significantly decreased following hypoxia treatment at all three timepoints(P<0.01),except for CHX10 at day 45(P>0.05).Moreover,the proportion of PAX6-/TUJ1+cells within the neural retinas increased considerably(P<0.01,<0.05,<0.05 respectively).CONCLUSION:Low oxygen promotes stemness and proliferation of neural retinas,suggesting that hypoxic conditions can enlarge the retinal progenitor cell pool in hiPSC-derived ROs.

Overexpression of Protein Phosphatase 2 Regulatory Subunit B"Alpha Promotes Glycolysis by Regulating Hexokinase 1 in Hepatocellular Carcinoma

Objective To investigate the regulatory relationship of Protein Phosphatase 2 Regulatory Subunit B"Alpha(PPP2R3A)and hexokinase 1(HK1)in glycolysis of hepatocellular carcinoma(HCC).Methods In HepG2 and Huh7 cells,PPP2R3A expression was silenced by small interfering RNA(siRNA)and overexpression by plasmid transfection.The PPP2R3A-related genes were searched by RNA sequencing.Glycolysis levels were measured by glucose uptake and lactate production.QRT-PCR,ELISA,western blot and immunofluorescence assay were performed to detect the changes of PPP2R3A and HK1.Cell proliferation,migration and invasion assay were used to study the roles of HK1 regulation by PPP2R3A.Results RNA sequencing data revealed that PPP2R3A siRNA significantly downregulated the expression of HK1.PPP2R3A gene overexpression promotes,while gene silencing suppresses,the level of HK1 and glycolysis in HCC cells.In HCC tissue samples,PPP2R3A and HK1 were colocalized in the cytoplasm,and their expression showed a positive correlation.HK1 inhibition abrogated the promotion of glycolysis,proliferation,migration and invasion by PPP2R3A overexpression in liver cancer cells.Conclusion Our findings showed the correlation of PPP2R3A and HK1 in the glycolysis of HCC,which reveals a new mechanism for the oncogenic roles of PPP2R3A in cancer.

Mesenchymal stem cells in tissue repairing and regeneration: Progress and future

The presence of mesenchymal progenitor cells within bone marrow has been known since the late nineteenth century. To date, mesenchymal stem cells (MSCs) have been isolated from several different connective tissues, such as adipose tissue, muscle, placenta, umbilical cord matrix, blood, liver, and dental pulp. Bone marrow, however, is still one of the major sources of MSCs for preclinical and clinical research. MSCs were first evaluated for regenerative applications and have since been shown to directly influence the immune system and to promote neovascularization of ischemic tissues. These observations have prompted a new era of MSC transplantation as a treatment for various diseases. In this review, we summarize the important studies that have investigated the use of MSCs as a therapeutic agent for regenerative medicine, immune disorders, cancer, and gene therapy. Furthermore, we discuss the mechanisms involved in MSC-based therapies and clinical-grade MSC manufacturing.

CAPE promotes the expansion of human umbilical cord blood-derived hematopoietic stem and progenitor cells in vitro

Due to the low number of collectable stem cells from single umbilical cord blood(UCB)unit,their initial uses were limited to pediatric therapies.Clinical applications of UCB hematopoietic stem and progenitor cells(HSPCs)would become feasible if there were a culture method that can effectively expand HSPCs while maintaining their self-renewal capacity.In recent years,numerous attempts have been made to expand human UCB HSPCs in vitro.In this study,we report that caffeic acid phenethyl ester(CAPE),a small molecule from honeybee extract,can promote in vitro expansion of HSPCs.Treatment with CAPE increased the percentage of HSPCs in cultured mononuclear cells.Importantly,culture of CD34+HSPCs with CAPE resulted in a significant increase in total colony-forming units and high proliferative potential colony-forming units.Burst-forming unit-erythroid was the mostly affected colony type,which increased more than 3.7-fold in 1μg mL 1CAPE treatment group when compared to the controls.CAPE appears to induce HSPC expansion by upregulating the expression of SCF and HIF1-α.Our data suggest that CAPE may become a potent medium supplement for in vitro HSPC expansion.

Research status and prospect of stem cells in the treatment of diabetes mellitus

Beta cell mass and function are decreased to varying degrees in diabetes. Islet cell replacement or regenerative therapy may offer great therapeutic promise to people with diabetes. In addition to primary pancreatic cells, recent studies on regeneration of functional insulin producing cells (IPCs) revealed that several alternative cell sources, including embryonic stem cells, induced pluripotent stem cells and adult stem cells, can generate IPCs by differentiation, reprogramming, and trans-differentiation. In this review, we discuss stem cells as a potential alternative cell source for the treatment of diabetes.

Prostaglandin E2 promotes hematopoietic development from human embryonic stem cells

Recent studies have suggested that prostaglan-din(PG)E2(PGE2)and the prostaglandin pathway are essential for hematopoietic stem cell growth and develop-ment.However,similar studies on hematopoietic commit-ment from human embryonic stem cells(hESCs)are still limited.Here we report that the addition of PGE2 promotes hematopoietic differentiation of hESCs.The induced cells from hESCs/OP9 co-culture and in the presence of PGE2 were characterized by reverse transcription-PCR(RT-PCR),flow cytometry,colony-forming assays and Wright-Giemsa staining.Our results demonstrated that PGE2 exposure could alter the gene expression pattern and morphology of co-cultured hESCs and resulted in a robust hematopoietic differentiation with higher frequencies of CD34+and CD45+cells.Furthermore,the Smad signaling pathway may be involved in PGE2 and OP9 induced hematopoietic differentiation of hESCs.This research may improve our knowledge of stem cell regulation and hopefully lead to better stem cell-based therapeutic options.

From stem cells to red blood cells:how far away from the clinical application?

The generation of red blood cells(RBCs)from stem cells provides a solution for deficiencies in blood transfusion.Currently,primary hematopoietic stem cells,embryonic stem cells and induced pluripotent stem cells have shown the potential to produce fully mature RBCs.Here,we discuss the advantages,induction protocols,progress and possible clinical applications of stem cells in RBC production.

MicroRNA-125b Induces Cancer Cell Apoptosis Through Suppression of Bcl-2 Expression

MicroRNAs （miRNAs） are small, noncoding RNAs which can often act as an oncogene or a tumor suppressor. Several miRNAs are associated with the development of hepatoceUular carcinoma （HCC）. We demonstrated that miR-125b significantly suppresses HCC cell proliferation and promotes apoptosis by inhibiting the gene expression of the anti-apoptotic protein, Bcl-2. Bioinformatic analysis indicated that the 3tUTR of Bcl-2 has binding sites for miR-I25b, Luciferase reporter assay confirmed the ability of miR-125b to dramatically suppress Bcl-2 transcription, suggesting that Bcl-2 is a target gene for miR-125b. We concluded that miR-125b acts as a tumor suppressor in hepatic tumor development by targeting Bcl-2 and inducing cancer celt apoptosis.

Advances in cell lineage reprogramming

As a milestone breakthrough of stem cell and regenerative medicine in recent years, somatic cell reprogramming has opened up new applications of regenerative medicine by breaking through the ethical shackles of embryonic stern cells. However, induced pluripo- tent stem （iPS） cells are prepared with a complicated protocol that results in a low reprogramming rate. To obtain differentiated target cells, iPS cells and embryonic stem cells still need to be induced using step-by-step procedures. The safety of induced target cells from iPS cells is currently a further concerning matter. More broadly conceived is lineage reprogramming that has been investigated since 1987. Adult stem cell plasticity, which triggered interest in stem cell research at the end of the last century, can also be included in the scope of lineage reprogramming. With the promotion of iPS cell research, lineage reprogramming is now considered as one of the most promising fields in regenerative medicine, will hopefully lead to customized, personalized therapeutic options for patients in the future.

Sera proteomic features of active and recovered COVID-19 patients:potential diagnostic and prognostic biomarkers

Dear Editor,The early diagnosis and prognosis of COVID-19 remain major challenges.At present,there are few studies focusing on the changes of sera proteome betAA/een active and recovered COVID-19 patients,and almost no biomarkers in sera are used to predict the function disorder of the injured tissues and organs in COVID-19 patients.In this study,we applied sera proteomics in the active and recovered COVID-19 patients,as well as healthy volunteers,combining with pathological staining of the patients'tissues to identify the potential prognosis biomarkers that can reflect specific organ damage.

Pathological features of COVID-19-associated lung injury:a preliminary proteomics report based on clinical samples

The COVID-19 pandemic has emerged as a global health emergency due to its association with severe pneumonia and relative high mortality.However,the molecular characteristics and pathological features underlying COVID-19 pneumonia remain largely unknown.To characterize molecular mechanisms underlying COVID-19 pathogenesis in the lung tissue using a proteomic approach,fresh lung tissues were obtained from newly deceased patients with COVID-19 pneumonia.After virus inactivation,a quantitative proteomic approach combined with bioinformatics analysis was used to detect proteomic changes in the SARS-CoV-2-infected lung tissues.We identified significant differentially expressed proteins involved in a variety of fundamental biological processes including cellular metabolism,blood coagulation,immune response,angiogenesis,and cell microenvironment regulation.Several inflammatory factors were upregulated,which was possibly caused by the activation of NF-κB signaling.Extensive dysregulation of the lung proteome in response to SARS-CoV-2 infection was discovered.Our results systematically outlined the molecular pathological features in terms of the lung response to SARS-CoV-2 infection,and provided the scientific basis for the therapeutic target that is urgently needed to control the COVID-19 pandemic.

Proteomic identification of new diagnostic biomarkers of early-stage cutaneousmycosis fungoides

Dear editor,Mycosis fungoides(MF),the most common subtype of cutaneous T cell lymphoma,is a rare disease[1,2].Patients with early-stageMF have a 5-year overall survival between 88%and 100%[3].In patients with advanced MF,the skin may present with tumors and erythroderma,and the median survival of patients with lymph node and visceral metastasis is 13 months[4].Therefore,it is important to achieve an early diagnosis to improve prognosis[5].

Pathological features of COVID-19-associated liver injury-a preliminary proteomics report based on clinical samples

Dear Editor,Almost one-half of COVID-19 patients have symptoms of liver injury.However,the molecular characteristics in the COVID-19 liver remain unknown.Therefore,the need for long-term medication for recovery make it imperative to study the infectivity and pathogenicity of SARS-CoV-2 in the liver.Here,we have identifed signifcant proteomic changes for the first time in the liver of COVID-19 patients.We detected differential expression levels of several proteins that mediate characteristic cellular host responses elicited by SARS-CoV-2 infection in the liver.