Pleckstrin Homology-Like Domain, Family A, Member 1 (PHLDA1): A Multifaceted Cell Survival Factor that Drives Metabolic Disease

Pleckstrin homology-like domain, family A, member 1 (PHLDA1) is a multifaceted intracellular protein belonging to the evolutionarily conserved pleckstrin homology-related domain family. Its murine homologue, T-cell death-associated 51 (TDAG51) gene, was initially discovered for its role in activation-induced apoptosis in T-cell hybridomas. In recent years, PHLDA1 has received increased attention due to its association with obesity, fatty liver disease, diabetes, atherosclerosis, and cancer. Accumulating evidence also supports its role in endoplasmic reticulum stress signaling pathways as a crucial mediator of apoptosis, autophagy, and cell proliferation. In this review, the current knowledge of PHLDA1 gene and protein regulation, localization, and function is summarized. This review highlights the pro- and anti-apoptotic roles of PHLDA1 that contribute to vast array of metabolic diseases.

High glucose microenvironment and human mesenchymal stem cell behavior

High glucose(HG)culture conditions in vitro and persistent exposure to hyperglycemia in diabetes patients are detrimental to stem cells,analogous to any other cell type in our body.It interferes with diverse signaling pathways,i.e.mammalian target of rapamycin(mTOR)-phosphoinositide 3-kinase(PI3K)-Akt signaling,to impact physiological cellular functions,leading to low cell survival and higher cell apoptosis rates.While elucidating the underlying mechanism responsible for the apoptosis of adipose tissue-derived mesenchymal stem cells(MSCs),a recent study has shown that HG culture conditions dysregulate mTORPI3K-Akt signaling in addition to mitochondrial malfunctioning due to defective mitochondrial membrane potential(MtMP)that lowers ATP production.This organelle-level dysfunction energy-starves the cells and increases oxidative stress and ultrastructural abnormalities.Disruption of the mitochondrial electron transport chain produces an altered mitochondrial NAD+/NADH redox state as evidenced by a low NAD+/NADH ratio that primarily contributes to the reduced cell survival in HG.Some previous studies have also reported altered mitochondrial membrane polarity(causing hyperpolarization)and reduced mitochondrial cell mass,leading to perturbed mitochondrial homeostasis.The hostile microenvironment created by HG exposure creates structural and functional changes in the mitochondria,altering their bioenergetics and reducing their capacity to produce ATP.These are significant data,as MSCs are extensively studied for tissue regeneration and restoring their normal functioning in cell-based therapy.Therefore,MSCs from hyperglycemic donors should be cautiously used in clinical settings for cell-based therapy due to concerns of their poor sur-vival rates and increased rates of post engraftment proliferation.As hypergly-cemia alters the bioenergetics of donor MSCs,rectifying the loss of MtMP may be an excellent target for future research to restore the normal functioning of MSCs in hyperglycemic patients.

Cellular preconditioning and mesenchymal stem cell ferroptosis

In this editorial,we comment on the article published in the recent issue of the World Journal of Stem Cells.They focus on stem cell preconditioning to prevent ferroptosis by modulating the cystathionineγ-lyase/hydrogen sulfide(H_(2)S)pathway as a novel approach to treat vascular disorders,particularly pulmonary hypertension.Preconditioned stem cells are gaining popularity in regenerative medicine due to their unique ability to survive by resisting the harsh,unfavorable microenvironment of the injured tissue.They also secrete various paracrine factors against apoptosis,necrosis,and ferroptosis to enhance cell survival.Ferroptosis,a regulated form of cell death characterized by iron accumulation and oxidative stress,has been implicated in various pathologies encompassing dege-nerative disorders to cancer.The lipid peroxidation cascade initiates and sustains ferroptosis,generating many reactive oxygen species that attack and damage multiple cellular structures.Understanding these intertwined mechanisms provi-des significant insights into developing therapeutic modalities for ferroptosis-related diseases.This editorial primarily discusses stem cell preconditioning in modulating ferroptosis,focusing on the cystathionase gamma/H_(2)S ferroptosis pathway.Ferroptosis presents a significant challenge in mesenchymal stem cell(MSC)-based therapies;hence,the emerging role of H_(2)S/cystathionase gamma/H_(2) S signaling in abrogating ferroptosis provides a novel option for therapeutic intervention.Further research into understanding the precise mechanisms of H_(2)S-mediated cytoprotection against ferroptosis is warranted to enhance the thera-peutic potential of MSCs in clinical settings,particularly vascular disorders.

The dichotomous role of TGF-β in controlling liver cancer cell survival and proliferation

Hepatocellular carcinoma(HCC) is the major form of primary liver cancer and one of the most prevalent and life-threatening malignancies globally. One of the hallmarks in HCC is the sustained cell survival and proliferative signals, which are determined by the balance between oncogenes and tumor suppressors.Transforming growth factor beta(TGF-β) is an effective growth inhibitor of epithelial cells including hepatocytes, through induction of cell cycle arrest, apoptosis, cellular senescence, or autophagy. The antitumorigenic effects of TGF-β are bypassed during liver tumorigenesis via multiple mechanisms.Furthermore, along with malignant progression, TGF-β switches to promote cancer cell survival and proliferation. This dichotomous nature of TGF-β is one of the barriers to therapeutic targeting in liver cancer. Thereafter, understanding the underlying molecular mechanisms is a prerequisite for discovering novel antitumor drugs that may specifically disable the growth-promoting branch of TGF-β signaling or restore its tumor-suppressive arm. This review summarizes how TGF-β inhibits or promotes liver cancer cell survival and proliferation, highlighting the functional switch mechanisms during the process.

The CARMA3-BCL10-MALT1 （CBM） complex contributes to DNA damage-induced NF-κB activation and cell survival

Dear Editor,Chemotherapy is one of major means for cancer treatments, and many of chemotherapeutic drugs are DNA damaging agents that reduce tumor growth through triggering cancer cell apoptosis or necrosis. Following DNA damage, ataxia telangiectasia mutated （ATM）, a protein kinase, was acti- vated and a cytosolic complex containing ATM, NEMO, RIP1 were formed （Biton and Ashkenazi, 2011）.

A role for mitogen-activated protein kinase phosphatase 1(MKP1) in neural cell development and survival

The mitogen-activated protein kinase（MAPK）pathways are a group of conserved intracellular signalling pathways present in most cells including neurons and glia.These pathways respond to a variety of stimuli including growth factors,cytokines and oxidative stress to generate appropriate cellular responses such as modulation of gene expression,cell proliferation,differentiation and survival as well as the stress response（Korhonen and Moilanen,2014）.

Experimental study of the effect of adipose stromal vascular fraction cells on the survival rate of fat transplantation

Objective To investigate the effect of adipose stromal vascular fraction cells(SVFs)on the survival rate of fat ransplantation.Methods 0.5mL autologous fat tissue was mixed with: ① DiI-labeled autologous SVFs (Group A);②

Macrophage depletion and Schwann cell transplantation reduce cyst size after rat contusive spinal cord injury

Schwann cell transplantation is a promising therapy for the treatment of spinal cord injury（SCI） and is currently in clinical trials.In our continuing efforts to improve Schwann cell transplantation strategies,we sought to determine the combined effects of Schwann cell transplantation with macrophage depletion.Since macrophages are major inflammatory contributors to the acute spinal cord injury,and are the major phagocytic cells,we hypothesized that transplanting Schwann cells after macrophage depletion will improve cell survival and integration with host tissue after SCI.To test this hypothesis,rat models of contusive SCI at thoracic level 8 were randomly subjected to macrophage depletion or not.In rat subjected to macrophage depletion,liposomes filled with clodronate were intraperitoneally injected at 1,3,6,11,and 18 days post injury.Rats not subjected to macrophage depletion were intraperitoneally injected with liposomes filled with phosphate buffered saline.Schwann cells were transplanted 1 week post injury in all rats.Biotinylated dextran amine（BDA） was injected at thoracic level 5 to evalute axon regeneration.The Basso,Beattie,and Bresnahan locomotor test,Gridwalk test,and sensory test using von Frey filaments were performed to assess functional recovery.Immunohistochemistry was used to detect glial fibrillary acidic protein,neurofilament,and green fluorescent protein（GFP）,and also to visulize BDA-labelled axons.The GFP labeled Schwann cell and cyst and lesion volumes were quantified using stained slides.The numbers of BDA-positive axons were also quantified.At 8 weeks after Schwann cell transplantation,there was a significant reduction in cyst and lesion volumes in the combined treatment group compared to Schwann cell transplantation alone.These changes were not associated,however,with improved Schwann cell survival,axon growth,or locomotor recovery.Although combining Schwann cell transplantation with macrophage depletion does improve histopathology of the injury site,the effect on axon growth and behavioral recovery appears no better than what can be achieved with Schwann cell transplants alone.

Long noncoding RNA HAND2-AS1 re duce d the viability of hepatocellular carcinoma via targeting microRNA-300/SOCS5 axis

Background:Hepatocellular carcinoma(HCC)is one of the most prevalent human cancers with high mortality.Long non-coding RNA heart and neural crest derivatives expressed 2 anti-sense 1(HAND2-AS1)is down-regulated in several cancers including HCC,yet the precise mechanisms how HAND2-AS1 regulates cell survival in HCC remains poorly understood.Methods:The expression levels of HAND2-AS1 and miR-300 were measured using quantitative real-time PCR.The protein levels of suppressor of cytokine signaling 5(SOCS5),Bcl-2,Bax and cleaved caspase-3 were determined by Western blot.Cell viability and cell proliferation were assessed using cell counting kit-8 and clone formation assay,respectively.Cell apoptosis was detected using flow cytometry.The interactions between HAND2-AS1 and miR-300,miR-300 and SOCS5 were validated using luciferase reporter assay.Results:HAND2-AS1 was down-regulated in HCC tissues and cell lines,and the expression level of HAND2-AS1 was positively correlated to patient survival.HAND2-AS1 over-expression reduced viability and proliferation in HCC cells.Elevated HAND2-AS1 level induced apoptosis in HCC cells,accompanied with increased Bax and cleaved caspase-3 levels and decreased Bcl-2 level.We also validated that HAND2-AS1 acted as a sponge of miR-300,and there was a negative correlation between expression levels of HAND2-AS1 and miR-300 in HCC tissues.Furthermore,we found that SOCS5 was a downstream target of miR-300.In addition,miR-300 mimics abolished HAND2-AS1-mediated inhibition of cell viability and proliferation.miR-300 mimics also reversed the HAND2-AS1-induced apoptosis in HCC cells.Conclusion:lncRNA HAND2-AS1 inhibits proliferation in HCC through regulating miR-300/SOCS5 axis.

Modulation of cell physiology under hypoxia in pancreatic cancer

In solid tumors,the development of vasculature is,to some extent,slower than the proliferation of the different types of cells that form the tissue,both cancer and stroma cells.As a consequence,the oxygen availability is compromised and the tissue evolves toward a condition of hypoxia.The presence of hypoxia is variable depending on where the cells are localized,being less extreme at the periphery of the tumor and more severe in areas located deep within the tumor mass.Surprisingly,the cells do not die.Intracellular pathways that are critical for cell fate such as endoplasmic reticulum stress,apoptosis,autophagy,and others are all involved in cellular responses to the low oxygen availability and are orchestrated by hypoxia-inducible factor.Oxidative stress and inflammation are critical conditions that develop under hypoxia.Together with changes in cellular bioenergetics,all contribute to cell survival.Moreover,cell-to-cell interaction is established within the tumor such that cancer cells and the microenvironment maintain a bidirectional communication.Additionally,the release of extracellular vesicles,or exosomes,represents short and long loops that can convey important information regarding invasion and metastasis.As a result,the tumor grows and its malignancy increases.Currently,one of the most lethal tumors is pancreatic cancer.This paper reviews the most recent advances in the knowledge of how cells grow in a pancreatic tumor by adapting to hypoxia.Unmasking the physiological processes that help the tumor increase its size and their regulation will be of major relevance for the treatment of this deadly tumor.

Abnormal lipid synthesis as a therapeutic target for cancer stem cells

Cancer stem cells(CSCs)comprise a subpopulation of cancer cells with stem cell properties,which exhibit the characteristics of high tumorigenicity,self-renewal,and tumor initiation and are associated with the occurrence,metastasis,therapy resistance,and relapse of cancer.Compared with differentiated cells,CSCs have unique metabolic characteristics,and metabolic reprogramming contributes to the self-renewal and maintenance of stem cells.It has been reported that CSCs are highly dependent on lipid metabolism to maintain stemness and satisfy the requirements of biosynthesis and energy metabolism.In this review,we demonstrate that lipid anabolism alterations promote the survival of CSCs,including de novo lipogenesis,lipid desaturation,and cholesterol synthesis.In addition,we also emphasize the molecular mechanism underlying the relationship between lipid synthesis and stem cell survival,the signal transduction pathways involved,and the application prospect of lipid synthesis reprogramming in CSC therapy.It is demonstrated that the dependence on lipid synthesis makes targeting of lipid synthesis metabolism a promising therapeutic strategy for eliminating CSCs.Targeting key molecules in lipid synthesis will play an important role in anti-CSC therapy.

Construction of a plasmid for human brain-derived neurotrophic factor and its effect on retinal pigment epithelial cell viability

Several studies have investigated the protective functions of brain-derived neurotrophic factor（BDNF） in retinitis pigmentosa. However, a BDNF-based therapy for retinitis pigmentosa is not yet available. To develop an efficient treatment for fundus disease, an eukaryotic expression plasmid was generated and used to transfect human 293 T cells to assess the expression and bioactivity of BDNF on acute retinal pigment epithelial-19（ARPE-19） cells, a human retinal epithelial cell line. After 96 hours of co-culture in a Transwell chamber, ARPE-19 cells exposed to BDNF secreted by 293 T cells were more viable than ARPE-19 cells not exposed to secreted BDNF. Western blot assay showed that Bax levels were downregulated and that Bcl-2 levels were upregulated in human ARPE-19 cells exposed to BDNF. Furthermore, 293 T cells transfected with the BDNF gene steadily secreted the protein. The powerful anti-apoptotic function of this BDNF may be useful for the treatment of retinitis pigmentosa and other retinal degenerative diseases.

Protective effect of insulin and glucose at different concentrations on penicillin-induced astrocyte death on the primer astroglial cell line

Astrocytes perform many functions in the brain and spinal cord.Glucose metabolism is important for astroglial cells and astrocytes are the only cells with insulin receptors in the brain.The common antibiotic penicillin is also a chemical agent that causes degenerative effect on neuronal cell.The aim of this study is to show the effect of insulin and glucose at different concentrations on the astrocyte death induced by penicillin on primer astroglial cell line.It is well known that intracranial penicillin treatment causes neuronal cell death and it is used for experimental epilepsy model commonly.Previous studies showed that insulin and glucose might protect neuronal cell in case of proper concentrations.But,the present study is about the effect of insulin and glucose against astrocyte death induced by penicillin.For this purpose,newborn rat brain was extracted and then mechanically dissociated to astroglial cell suspension and finally grown in culture medium.Clutters were maintained for 2 weeks prior to being used in these experiments.Different concentrations of insulin（0,1,3 nM）and glucose（0,3,30 mM）were used in media without penicillin and with 2 500μM penicillin.Penicillin decreased the viability of astroglial cell seriously.The highest cell viability appeared in medium with 3 nM insulin and 3 mM glucose but without penicillin.However,in medium with penicillin,the best cell survival was in medium with 1 nM insulin but without glucose. We concluded that insulin and glucose show protective effects on the damage induced by penicillin to primer astroglial cell line.Interestingly,cell survival depends on concentrations of insulin and glucose strongly.The results of this study will help to explain cerebrovascular pathologies parallel to insulin and glucose conditions of patient after intracranial injuries.

The effects of 2-Bromopropane on Viability and TestosteroneProduction Ability of Rat Leydig Cells in Primary Culture

Epidemiological surveys and animal experiments have shown that 2-bromopropane induces oligozoospermia in exposed workers and inhibits spermatogensis in laborratory animals. However, themechanism by which 2-bromopropane exerts its effects is unknown. To this end, we examined the formation of testosterone by the Leydig cells and their survival of these cells in the Presence of differ-ent concentrations of 2-bromopropane in vitro. Leydig cells were isolated following vascular Perfu-sion, enzymatic dissociation and Percoll gradient centrifugation techniques. The cells were cultured in culture dishes. After 8 h, different cultures were exposed to 2-bromopropane at concentrations of 0.01 mmol/L, 0.10 mmol/L and 1.00 mmol/L. In order to stimulate Leydig cells to secrete testos-terone, human chorionic gonadotropin (hCG) was also added. Cell viability was determined using the trypan blue dye exclusion test and cell numbers were counted by hemocytometer. Testosterone secretion was detected by radioimmunoassay. The cell viability decreased after exposure to 2-bromo-propane in a dose-dependent way, but no morphological change was observed. The cell number de-creased in the 2-bromopropane-treated cultures. The secretion of testosterone did not manifest de -tectable changes in the culture treated with 0.10 mmol/L and 0.01 mmol/L of 2-bromopropane;however, it decreased significantly (P < 0. 02) in the Presence of 1.00 mmol/L. Therefore, ourresults strongly suggest that 2-bromopropane may exert its cytotoxic effects on heydig cells in vitro.We speculate that the decrease in the numbers of Leydig cells caused by 2-bromopropane was medi-ated by a feedback mechanism resulting from a lower testosterone concentration.

Minibrain-related kinase/dual-specificity tyrosine-regulated kinase 1B implication in stem/cancer stem cells biology

Dual-specificity tyrosine phosphorylation-regulated kinase 1B(DYRK1B),also known as minibrain-related kinase(MIRK)is one of the best functionally studied members of the DYRK kinase family.DYRKs comprise a family of protein kinases that are emerging modulators of signal transduction pathways,cell proliferation and differentiation,survival,and cell motility.DYRKs were found to participate in several signaling pathways critical for development and cell homeostasis.In this review,we focus on the DYRK1B protein kinase from a functional point of view concerning the signaling pathways through which DYRK1B exerts its cell type-dependent function in a positive or negative manner,in development and human diseases.In particular,we focus on the physiological role of DYRK1B in behavior of stem cells in myogenesis,adipogenesis,spermatogenesis and neurogenesis,as well as in its pathological implication in cancer and metabolic syndrome.Thus,understanding of the molecular mechanisms that regulate signaling pathways is of high importance.Recent studies have identified a close regulatory connection between DYRK1B and the hedgehog(HH)signaling pathway.Here,we aim to bring together what is known about the functional integration and cross-talk between DYRK1B and several signaling pathways,such as HH,RAS and PI3K/mTOR/AKT,as well as how this might affect cellular and molecular processes in development,physiology,and pathology.Thus,this review summarizes the major known functions of DYRK1B kinase,as well as the mechanisms by which DYRK1B exerts its functions in development and human diseases focusing on the homeostasis of stem and cancer stem cells.

A Meta-analysis Reveals Prognostic Role of Programmed Death Ligand-1 in Asian Patients with Non-small Cell Lung Cancer

Accumulating studies explored the clinicopathologic and prognostic value of programmed death ligand-1（PD-L1） in non-small cell lung cancer（NSCLC）, but the results were controversial. We therefore conducted a meta-analysis to evaluate the predictive role of PD-L1 in NSCLC patients. We systematically collected relevant studies from Pub Med, Embase, Web of Science and China National Knowledge Infrastructure. The pooled hazard ratios（HRs） with 95% confidence intervals（CIs） for overall survival（OS）, and odd ratios（ORs） with 95% CIs for clinicopathologic factors were calculated. A total of 15 studies involving 3605 patients were included in this meta-analysis. The results showed no prognostic role of PD-L1 in the whole patients（HR=1.60, 95% CI： 0.88–2.89, P=0.123）. Subgroup analysis showed that PD-L1 was associated with decreased OS in Asian patients（HR=2.00, 95% CI： 1.55–2.57, P〈0.001）. Among all the clinicopathologic factors, PD-L1 overexpression was significantly in relevance with poor tumor cell differentiation（HR=1.84, 95% CI： 1.49–2.28, P〈0.001）, late stage（HR=1.21, 95% CI： 1.02–1.43, P=0.026） and anaplastic lymphoma kinase（ALK） translocation（HR=2.63, 95% CI： 1.08–6.40, P=0.034）, but not with other factors. In conclusion, our meta-analysis demonstrated that PD-L1 has a prognostic role in Asian patients with NSCLC.

Priming mesenchymal stem cells to develop “super stem cells”

The stem cell pre-treatment approaches at cellular and sub-cellular levels encompass physical manipulation of stem cells to growth factor treatment,genetic manipulation,and chemical and pharmacological treatment,each strategy having advantages and limitations.Most of these pre-treatment protocols are non-combinative.This editorial is a continuum of Li et al’s published article and Wan et al’s editorial focusing on the significance of pre-treatment strategies to enhance their stemness,immunoregulatory,and immunosuppressive properties.They have elaborated on the intricacies of the combinative pre-treatment protocol using pro-inflammatory cytokines and hypoxia.Applying a well-defined multi-pronged combinatorial strategy of mesenchymal stem cells(MSCs),pre-treatment based on the mechanistic understanding is expected to develop“Super MSCs”,which will create a transformative shift in MSC-based therapies in clinical settings,potentially revolutionizing the field.Once optimized,the standardized protocols may be used with slight modifications to pre-treat different stem cells to develop“super stem cells”with augmented stemness,functionality,and reparability for diverse clinical applications with better outcomes.

Protective mechanisms of micro RNA-27a against oxygen-glucose deprivation-induced injuries in hippocampal neurons

Hypoxic injuries during fetal distress have been shown to cause reduced expression of micro RNA-27a（mi R-27a）,which regulates sensitivity of cortical neurons to apoptosis.We hypothesized that miR-27 a overexpression attenuates hypoxia- and ischemia-induced neuronal apoptosis by regulating FOXO1,an important transcription factor for regulating the oxidative stress response.miR-27 a mimic was transfected into hippocampal neurons to overexpress miR-27 a.Results showed increased hippocampal neuronal viability and decreased caspase-3 expression.The luciferase reporter gene system demonstrated that mi R-27 a directly binded to FOXO1 3′UTR in hippocampal neurons and inhibited FOXO1 expression,suggesting that FOXO1 was the target gene for mi R-27 a.These findings confirm that mi R-27 a protects hippocampal neurons against oxygen-glucose deprivation-induced injuries.The mechanism might be mediated by modulation of FOXO1 and apoptosis-related gene caspase-3 expression.

TRAF2 regulates T cell immunity by maintaining a Tpl2-ERK survival signaling axis in effector and memory CD8 T cells

Generation and maintenance of antigen-specific effector and memory T cells are central events in immune responses against infections.We show that TNF receptor-associated factor 2(TRAF2)maintains a survival signaling axis in effector and memory CD8 T cells required for immune responses against infections.This signaling axis involves activation of Tpl2 and its downstream kinase ERK by NF-κB-inducing kinase(NIK)and degradation of the proapoptotic factor Bim.NIK mediates Tpl2 activation by stimulating the phosphorylation and degradation of the Tpl2 inhibitor p105.Interestingly,while NIK is required for Tpl2-ERK signaling under normal conditions,uncontrolled NIK activation due to loss of its negative regulator,TRAF2,causes constitutive degradation of p105 and Tpl2,leading to severe defects in ERK activation and effector/memory CD8 T cell survival.Thus,TRAF2 controls a previously unappreciated signaling axis mediating effector/memory CD8 T cell survival and protective immunity.

ROR2 regulates the survival of murine osteosarcoma cells in lung capillaries

Aim:Lung metastasis is a leading cause of death in patients with osteosarcoma(OS).No effective therapy exists that improves the five-year overall survival rate of OS patients with metastasis.Therefore,finding novel therapeutic targets will help develop new treatment strategies for OS patients with lung metastasis.Methods:Based on analysis of gene expression profiles between sublines of the Dunn OS LM8 cell line with high(LM8-H)and low(LM8-L)metastatic ability,we have identified Wnt signal-related genes that play an important role in lung metastasis of OS.Function of the genes was investigated by establishing sublines of gene knockout and assessing their metastatic ability using a mouse lung metastasis model.The molecular mechanism underlying the function of the genes was further investigated by in vitro experiments.Results:We have identified that receptor tyrosine kinase-like orphan receptor 2(ROR2),a receptor of the non-canonical Wnt signaling pathway,was involved in OS cell survival in lung capillaries during metastasis.LM8-H knocked out of Ror2(H/Ror2-KO)significantly reduced lung metastasis by decreasing the viability in lung capillaries 48 h after intravenous injection.In vitro study revealed that ROR2 increased anoikis resistance through AKT activation.Reconstitution of ROR2 expression in H/Ror2-KO cells restored their metastatic ability and viability in lung capillaries.Conclusion:The results demonstrate a novel ROR2 function in OS lung metastasis and may inform new treatment strategies for OS patients.