Exploration and evaluation of reporting quality of randomised controlled trials on blended learning in medical education.

Aims/Background Blended learning has been a commonly adopted teaching mode in the medical education community in recent years. Many studies have shown that the blended learning mode is superior to the traditional teaching mode. Nonetheless, pinpointing the specific advantages provided by blended teaching methods is challenging, since multiple elements influence their effectiveness. This study aimed to investigate the reliability of the conclusions of published randomised controlled trials (RCTs) on blended learning in medical education by assessing their quality, and to provide suggestions for future related studies. Methods Two investigators searched PUBMED and EMBASE, and assessed RCTs related to medical blended learning published from January 1, 2010 to December 31, 2021. The analysis of the overall quality of each report was based on the 2010 consolidated standard of reporting trials (CONSORT) Statement applying a 28-point overall quality score. We also conducted a multivariate assessment including year of publication, region of the trial, journal, impact factor, sample size, and the primary outcome. Results A total of 22 RCTs closely relevant to medical blended learning were eventually selected for study. The results demonstrated that half of the studies failed to explicitly describe at least 34% of the items in the 2010 CONSORT Statement. Medical blended learning is an emerging new teaching mode, with 95.45% of RCTs published since 2010. However, many issues that we consider crucial were not satisfactorily addressed in the selected RCTs. Conclusion Although the 2010 CONSORT Statement was published more than a decade ago, the quality of RCTs remains unsatisfactory. Some important items were inadequately reported in many RCTs such as sample size, blinding, and concealment. We encourage researchers who focus on the effects of blended learning in medical education to incorporate the guidelines in the 2010 CONSORT Statement when designing and conducting relevant research. Researchers, reviewers, and editors also need to work together to improve the quality of relevant RCTs in accordance with the requirements of the 2010 CONSORT Statement.

FGF21 alleviates adipose stem cell senescence via CD90 glycosylation-dependent glucose influx in remodeling healthy white adipose tissue.

The senescence of adipose stem cells (ASCs) impairs healthy adipose tissue remodeling, causing metabolic maladaptation to energy surplus. The intrinsic molecular pathways and potential therapy targets for ASC senescence are largely unclear. Here, we showed that visceral ASCs were prone to senescence that was caused by reactive oxygen species (ROS) overload, especially mitochondrial ROS. These senescent ASCs failed to sustain efficient glucose influx, pentose phosphate pathway (PPP) and redox homeostasis. We showed that CD90 silence restricted the glucose uptake by ASCs and thus disrupted their PPP and anti-oxidant system, resulting in ASC senescence. Notably, fibroblast growth factor 21 (FGF21) treatment significantly reduced the senescent phenotypes of ASCs by augmenting CD90 protein via glycosylation, which promoted glucose influx via the AKT-GLUT4 axis and therefore mitigated ROS overload. For diet-induced obese mice, chronic administration of low-dose FGF21 relieved their visceral white adipose tissue (VAT) dysfunction and systemic metabolic disorders. In particular, VAT homeostasis was restored in FGF21-treated obese mice, where ASC repertoire was markedly recovered, accompanied by CD90 elevation and anti-senescent phenotypes in these ASCs. Collectively, we reveal a molecular mechanism of ASC senescence by which CD90 downregulation interferes glucose influx into PPP and redox homeostasis. And we propose a FGF21-based strategy for healthy VAT remodeling, which targets CD90 glycosylation to correct ASC senescence and therefore combat obesity-related metabolic dysfunction.

Hepatocyte TIPE2 is a fasting-induced Raf-1 inactivator that drives hepatic gluconeogenesis to maintain glucose homeostasis.

BACKGROUND: The liver regulates metabolic balance during fasting-feeding cycle. Hepatic adaptation to fasting is precisely modulated on multiple levels. Tumor necrosis factor-α-induced protein 8-like 2 (TIPE2) is a negative regulator of immunity that reduces several liver pathologies, but its physiological roles in hepatic metabolism are largely unknown. METHODS: TIPE2 expression was examined in mouse liver during fasting-feeding cycle. TIPE2-knockout mice, liver-specific TIPE2-knockout mice, liver-specific TIPE2-overexpressed mice were examined for fasting blood glucose and pyruvate tolerance test. Primary hepatocytes or liver tissues from these mice were evaluated for glucose production, lipid accumulation, gene expression and regulatory pathways. TIPE2 interaction with Raf-1 and TIPE2 transcription regulated by PPAR-α were examined using gene overexpression or knockdown, co-immunoprecipitation, western blot, luciferase reporter assay and DNA-protein binding assay. RESULTS: TIPE2 expression was upregulated in fasted mouse liver and starved hepatocytes, which was positively correlated with gluconeogenic genes. Liver-specific TIPE2 deficiency impaired blood glucose homeostasis and gluconeogenic capacity in mice upon fasting, while liver-specific TIPE2 overexpression elevated fasting blood glucose and hepatic gluconeogenesis in mice. In primary hepatocytes upon starvation, TIPE2 interacted with Raf-1 to accelerate its ubiquitination and degradation, resulting in ERK deactivation and FOXO1 maintenance to sustain gluconeogenesis. During prolonged fasting, hepatic TIPE2 deficiency caused aberrant activation of ERK-mTORC1 axis that increased hepatic lipid accumulation via lipogenesis. In hepatocytes upon starvation, PPAR-α bound with TIPE2 promoter and triggered its transcriptional expression. CONCLUSIONS: Hepatocyte TIPE2 is a PPAR-α-induced Raf-1 inactivator that sustains hepatic gluconeogenesis and prevents excessive hepatic lipid accumulation, playing beneficial roles in hepatocyte adaptation to fasting.

SOHLH2 Suppresses Angiogenesis by Downregulating HIF1α Expression in Breast Cancer.

SOHLH2 has been demonstrated the downregulation in various cancers and the involvement in tumor growth and metastasis. However, the function of SOHLH2 on tumor angiogenesis and the underlying molecular mechanisms have not been interrogated. IHC staining results revealed that SOHLH2 was negatively associated with microvessel density (MVD), tumor size, histology grade, and metastasis. Overexpression of SOHLH2 inhibited the angiogenic behavior of human umbilical vein endothelial cells (HUVEC) by a tumor cell-mediated paracrine signal, while knockdown of SOHLH2 promoted HUVEC angiogenic behavior. Ectopic SOHLH2 expression remarkably suppressed tumor growth and MVD in xenograft tumors, downregulated the expression of hypoxia inducible factor-1 alpha (HIF1α)-mediated proangiogenic genes in vivo and in vitro, while knockdown of SOHLH2 had an opposite result. Furthermore, we found that upregulation of HIF1α reversed SOHLH2-induced suppression of breast cancer angiogenesis, while KC7F2, the inhibitor of HIF1α, could attenuate the promotion of angiogenesis by SOHLH2 silencing. Using Chromatin immunoprecipitation and luciferase reporter assays, we validated that SOHLH2 could directly bind to HIF1α promoter and repress its transcriptional activity. Collectively, SOHLH2 suppresses breast cancer angiogenesis by downregulating HIF1α transcription and may be a potential biomarker for anti-angiogenesis therapy. IMPLICATIONS: SOHLH2 directly represses HIF1α-mediated angiogenesis and serves as an important inhibitor of angiogenesis in breast cancer.

Melatonin Protects Neural Stem Cells Against Tri-Ortho-Cresyl Phosphate-Induced Autophagy.

Tri-ortho-cresyl phosphate (TOCP) is an extensively used organophosphate in industry. It has been proven to lead to toxicity in different organ systems, especially in the nervous system. Neural stem cells (NSCs) play important roles in both embryonic and adult nervous systems. However, whether TOCP induces cytotoxicity in embryonic NSCs remains unclear. In this study, mouse NSCs were exposed to different concentrations of TOCP for 24 h. The results showed that TOCP led to impaired proliferation of NSCs and induced the autophagy of NSCs by increasing the generation of intracellular reactive oxygen species (ROS) and decreasing the phosphorylation of extracellular regulated protein kinase (ERK1/2). Melatonin has been reported to exert neuroprotective effects via various mechanisms. Therefore, we further investigate whether melatonin has potential protective effects against TOCP-induced cytotoxicity on NSCs. Our data showed that melatonin pretreatment attenuated TOCP-induced autophagy by suppressing oxidative stress and restoring ERK1/2 phosphorylation consistently. Taken together, the results indicated that TOCP induced the autophagy in mouse NSCs, and melatonin may effectively protect NSCs against TOCP-induced autophagy.

CD90 serves as differential modulator of subcutaneous and visceral adipose-derived stem cells by regulating AKT activation that influences adipose tissue and metabolic homeostasis.

BACKGROUND: White adipose tissue includes subcutaneous and visceral adipose tissue (SAT and VAT) with different metabolic features. SAT protects from metabolic disorders, while VAT promotes them. The proliferative and adipogenic potentials of adipose-derived stem cells (ADSCs) are critical for maintaining adipose tissue homeostasis through driving adipocyte hyperplasia and inhibiting pathological hypertrophy. However, it remains to be elucidated the critical molecules that regulate different potentials of subcutaneous and visceral ADSCs (S-ADSCs, V-ADSCs) and mediate distinct metabolic properties of SAT and VAT. CD90 is a glycosylphosphatidylinositol-anchored protein on various cells, which is also expressed on ADSCs. However, its expression patterns and differential regulation on S-ADSCs and V-ADSCs remain unclear. METHODS: S-ADSCs and V-ADSCs were detected for CD90 expression. Proliferation, colony formation, cell cycle, mitotic clonal expansion, and adipogenic differentiation were assayed in S-ADSCs, V-ADSCs, or CD90-silenced S-ADSCs. Glucose tolerance test and adipocyte hypertrophy were examined in mice after silencing of CD90 in SAT. CD90 expression and its association with CyclinD1 and Leptin were analyzed in adipose tissue from mice and humans. Regulation of AKT by CD90 was detected using a co-transfection system. RESULTS: Compared with V-ADSCs, S-ADSCs expressed high level of CD90 and showed increases in proliferation, mitotic clonal expansion, and adipogenic differentiation, together with AKT activation and G1-S phase transition. CD90 silencing inhibited AKT activation and S phase entry, thereby curbing proliferation and mitotic clonal expansion of S-ADSCs. In vivo CD90 silencing in SAT inhibited S-ADSC proliferation, which caused adipocyte hypertrophy and glucose intolerance in mice. Furthermore, CD90 was highly expressed in SAT rather than in VAT in human and mouse, which had positive correlation with CyclinD1 but negative correlation with Leptin. CD90 promoted AKT activation through recruiting its pleckstrin homology domain to plasma membrane. CONCLUSIONS: CD90 is differentially expressed on S-ADSCs and V-ADSCs, and plays critical roles in ADSC proliferation, mitotic clonal expansion, and hemostasis of adipose tissue and metabolism. These findings identify CD90 as a crucial modulator of S-ADSCs and V-ADSCs to mediate distinct metabolic features of SAT and VAT, thus proposing CD90 as a valuable biomarker or target for evaluating ADSC potentials, monitoring or treating obesity-associated metabolic disorders.

Maternal hyperglycemia disturbs neocortical neurogenesis via epigenetic regulation in C57BL/6J mice.

Offspring of mothers with hyperglycemia during pregnancy have a higher incidence of long-term neuropsychiatric disorders than offspring from a normal pregnancy, indicating that neocortical neurogenesis might be affected by maternal hyperglycemia. A paucity of study evaluating the effects of hyperglycemia on neocortical neurogenetic differentiation of neural stem cells, and the mechanism remains unclear. We sought to investigate the the roles and possible molecular mechanism of maternal hyperglycemia on neocortical neurogenetic differentiation of neural stem cells. We established a mouse model of a hyperglycemic pregnancy to study effects of intrauterine exposure to maternal hyperglycemia on neocortical neurogenesis. We observed morphological changes in the neocortex and detected the neurogenetic differentiation of neural stem cells in offspring affected by high glucose levels. We investigated the regulatory network between epigenetic modification and transcription factors in differentiated neural stem cells under hyperglycemic conditions. Maternal hyperglycemia disturbs neocortical lamination in some non-malformed offspring. Our results suggested that hyperglycemia altered the early-born neuron fate and the distribution of newborn neurons in deep layers by promoting the earlier differentiation of neural stem cells. Altered histone acetylation and its regulation on the transcription of proneural genes might be correlated to the disrupted differentiation of neural stem cells and altered distribution of newborn projection neurons in the neocortex. Our data raised the possibility that maternal hyperglycemia in pregnancy disturbs the laminar distribution of neocortical projection neurons in some non-malformed offspring via epigenetic regulation on neural stem cell differentiation and the birthdate of neocortical neurons.

Effect of melatonin on neuronal differentiation requires CBP/p300-mediated acetylation of histone H3 lysine 14.

The transition from multipotent neural stem cells (NSCs) to terminally differentiated neurons is a multistep process, and the transition is finely regulated by transcription factors with basic helix-loop-helix (bHLH) motifs. Melatonin is an endogenous neurohormone with profound neurotrophic and neuroprotective effects both during the embryonic developmental stage and adulthood. The effects of melatonin on the differentiation of NSCs have been reported, and these effects may be responsible for its neuroprotective properties. However, the mechanisms underlying the effects of melatonin are not well understood. It is unclear whether melatonin affects the expression of bHLH factors at the onset of neuronal differentiation, and the molecular mechanisms involved still need to be further explored. Using mouse NSCs, we identified a novel role for melatonin in the epigenetic regulation of bHLH factors during neuronal differentiation. Our data showed that melatonin promoted neuronal differentiation by specifically increasing the acetylation of histone H3 lysine14 (H3K14). Increased H3K14 acetylation altered the chromatin state of the promoters of bHLH factors Neurogenin1 and NeuroD1 and activated their transcription; then, Neurogenin1 and NeuroD1 initiated and sustained the commitment to neuronal fates. As we know, CBP/p300 is an important class of histone acetyltransferases that acetylate histone H3K14, we found that melatonin activated the histone acetyltransferase activity of CREB-binding protein (CBP)/p300 via ERK signaling pathways. For the first time, we systematically showed the molecular mechanism of action of melatonin, which suggested that melatonin functions as a regulator of the acetylation-dependent gene expression network.

Abnormal Development of Dendrites in Adult-Born Rat Hippocampal Granule Cells Induced by Cyclophosphamide.

Although development of cognitive decline in cancer patients who receive chemotherapy is common, the underlying mechanism(s) remains to be identified. As abnormalities in adult hippocampal neurogenesis may serve as substrate for cognitive dysfunction, the present study examines the effect of cyclophosphamide (CPP), a widely prescribed chemotherapeutic agent, on dendritic development of adult-born hippocampal granule cells in the rat. CPP was intraperitoneally injected into male Sprague-Dawley rats once a week for four consecutive weeks. Four weeks and 1 week after the last dose of CPP, Morris water maze test and doublecortin (DCX) immunohistochemistry were carried out to determine the effects of CPP on cognitive function and the rate of hippocampal neurogenesis, respectively. Adult newborn hippocampal granule cells were labeled at the same day as the first dose of CPP and were examined 10 weeks after labeling. Results showed that cognitive decline induced by CPP was associated with both suppressed adult hippocampal neurogenesis and abnormal development of dendrites of newborn granule cells. The abnormalities of dendrites in newborn granule cells after CPP exposure included less dendritic branching, shorter total dendritic length, thinner and torturous dendritic shafts with intermittent appearances of varicosities, and lower spine densities of stubby and thin types along dendritic shafts, but an increased density of mushroom-like spines. Adult-born granule cells in the presence of CPP, a widely used anti-cancer medication, display abnormal dendritic morphologies and fewer dendritic spines which may underlie cognitive dysfunction.

Preconditioning of bone marrow mesenchymal stem cells with hydrogen sulfide improves their therapeutic potential.

Bone marrow mesenchymal stem cells (BMSCs) transplantation has shown great promises for treating various brain diseases. However, poor viability of transplanted BMSCs in injured brain has limited the therapeutic efficiency. Hypoxia-ischemic injury is one of major mechanisms underlying the survival of transplanted BMSCs. We investigated the mechanism of preconditioning of BMSCs with hydrogen sulfide (H2S), which has been proposed as a novel therapeutic strategy for hypoxia-ischemic injury. In this study, we demonstrated that preconditioning of NaHS, a H2S donor, effectively suppressed hypoxia-ischemic-induced apoptosis whereby the rise in Bax/Bcl-2 ratio. Further analyses revealed Akt and ERK1/2 pathways were involved in the protective effects of NaHS. In addition, NaHS preconditioning increased secretion of BDNF and VEGF in BMSCs. Consistent with in vitro data, transplantation of NaHS preconditioned BMSCs in vivo further enhanced the therapeutic effects of BMSCs on neuronal injury and neurological recovery, associated with increased vessel density and upregulation of BDNF and VEGF in the ischemic tissue. These findings suggest that H2S could enhance the therapeutic effects of BMSCs. The underlying mechanisms might be due to enhanced capacity of BMSCs and upregulation of protective cytokines in the hypoxia tissue.

Protein Palmitoylation Regulates Neural Stem Cell Differentiation by Modulation of EID1 Activity.

The functional significance of palmitoylation in the switch between self-renewal and differentiation of neural stem cells (NSCs) is not well defined, and the underlying mechanisms of protein palmitoylation are not well understood. Here, mouse NSCs were used as a model system and cell behavior was monitored in the presence of the protein palmitoylation inhibitor 2-bromopalmitate (2BRO). Our data show that 2BRO impaired the differentiation of NSCs into both neurons and glia and impaired NSC cell cycle exit. Moreover, the results show that palmitoylation modified E1A-like inhibitor of differentiation one (EID1) and this modification regulated EID1 degradation and CREB-binding protein (CBP)/p300 histone acetyltransferase activity at the switch between self-renewal and differentiation of NSCs. Our results extended the cellular role of palmitoylation, suggesting that it acts as a regulator in the acetylation-dependent gene expression network, and established the epigenetic regulatory function of palmitoylation in the switch between maintenance of multipotency and differentiation in NSCs.

Melatonin prevents neural tube defects in the offspring of diabetic pregnancy.

Melatonin, an endogenous neurohormone secreted by the pineal gland, has a variety of physiological functions and neuroprotective effects. However, its protective role on the neural tube defects (NTDs) was not very clear. The aim of this study was to investigate the effects of melatonin on the incidence of NTDs (including anencephaly, encephalocele, and spina bifida) of offspring from diabetic pregnant mice as well as its underlying mechanisms. Pregnant mice were given 10 mg/kg melatonin by daily i.p. injection from embryonic day (E) 0.5 until being killed on E11.5. Here, we showed that melatonin decreased the NTDs (especially exencephaly) rate of embryos exposed to maternal diabetes. Melatonin stimulated proliferation of neural stem cells (NSCs) under hyperglycemic condition through the extracellular regulated protein kinases (ERK) pathway. Furthermore, as a direct free radical scavenger, melatonin decreased apoptosis of NSCs exposed to hyperglycemia. In the light of these findings, it suggests that melatonin supplementation may play an important role in the prevention of neural malformations in diabetic pregnancy.

Immunohistochemical Study of Expression of Sohlh1 and Sohlh2 in Normal Adult Human Tissues.

The expression pattern of Sohlh1 (spermatogenesis and oogenesis specific basic helix-loop-helix 1) and Sohlh2 in mice has been reported in previous studies. Sohlh1 and Sohlh2 are specifically expressed in spermatogonia, prespermatogonia in male mice and oocytes of primordial and primary follicles in female mice. In this report, we studied the expression pattern of Sohlh1 and Sohlh2 in human adult tissues. Immunohistochemical staining of Sohlh1 and Sohlh2 was performed in 5 samples of normal ovaries and testes, respectively. The results revealed that Sohlh genes are not only expressed in oocytes and spermatogonia, but also in granular cells, theca cells, Sertoli cells and Leydig cells, and in smooth muscles of blood vessel walls. To further investigate the expression of Sohlh genes in other adult human tissues, we collected representative normal adult tissues developed from three embryonic germ layers. Compared with the expression in mice, Sohlhs exhibited a much more extensive expression pattern in human tissues. Sohlhs were detected in testis, ovary and epithelia developed from embryonic endoderm, ectoderm and tissues developed from embryonic mesoderm. Sohlh signals were found in spermatogonia, Sertoli cells and also Leydig cells in testis, while in ovary, the expression was mainly in oocytes of primordial and primary follicles, granular cells and theca cells of secondary follicles. Compared with Sohlh2, the expression of Sohlh1 was stronger and more extensive. Our study explored the expression of Sohlh genes in human tissues and might provide insights for functional studies of Sohlh genes.

Notch-1 signaling regulates astrocytic proliferation and activation after hypoxia exposure.

Activation of astrocyte has been implicated in the neonatal hypoxic brain injury. However, the mechanisms that control astrocytic activation and astrogliosis formation remain unknown. Here, we found that Notch-1 is upregulated and activated by hypoxia in astrocytes as confirmed by an increase in NICD and Hes-1 expression. Remarkably, blockade of Notch-1 signaling with the specific inhibitor DAPT suppressed astrocytic proliferation. In addition, both expression and secretion of inflammatory factor IL-1ß was inhibited in DAPT-pretreated astrocytes, while no significant change in TNF-α expression was detected. Most interestingly, GFAP and VEGF expression was suppressed by DAPT pretreatment in hypoxic astrocytes and further confirmed in neonatal rats following hypoxic brain injury. Furthermore, inhibition of Notch caused a remarkable decrease in NF-κB/p65 expression and translocation. Moreover, downregulation of either VEGF or NF-κB/p65 reduced astrocytic proliferation. Taken together, these results demonstrated that Notch-1 signaling was activated in hypoxic astrocytes and regulated astrocytic proliferation and activation by suppressing VEGF or NF-κB/p65 signaling pathway. Therefore, Notch signaling is a potential therapeutic strategy in hypoxia brain damage.

[Changes in the expression and phosphorylation state of autophagy-related protein ATG4 in nervous tissues of hens treated with tri-ortho-cresyl phosphate].

OBJECTIVE: To study the changes in the levels of authophagy-related proteins ATG4A and p-ATG4A in nervous tissue after treated with tri-ortho-cresyl phosphate and explore the possible pathogenesis of OPIDN. METHODS: In the first experiment, thirty hens were randomly divided into control group and 1 d, 5 d, 10 d and 21d treated groups, hens in treated groups were treated with TOCP by gavage at a single dosage of 600 mg/kg. In the second experiment, other thirty hens were also randomly divided into control group and 1 d, 5 d, 10 d and 21 d treated groups, hens in treated group were pretreated with PMSF by subcutaneous at a single dosage of 90 mg/kg. 24 h later, hens in intervention group was treated with TOCP by gavage at a single dosage of 600 mg/kg. The hens were killed at the corresponding time points, and collected their tibial nerves. The levels of ATG4A and p-ATG4A were measured by immunoblotting. RESULTS: compared with the control group, the levels of ATG4A decreased by36%, 43.7% and 41% at 1d, 5d and 10d in the intoxication groups (P < 0.05), the levels of p-ATG4A decreased by 22.5%, 25%and 21%at 1d, 5d and 10d in the intoxication group (P < 0.05). However, compared with the control group, there is no significant change in the levels of ATG4A and p-ATG4A in PMSF-pretreated groups. CONCLUSION: The intoxication of TOCP influence the levels of autophagy-related proteins ATG4A and p-ATG4A, which might be associated with the inhibition of autophagy activity in neurons of OPIDN.

Cytoprotective effect of melatonin against hypoxia/serum deprivation-induced cell death of bone marrow mesenchymal stem cells in vitro.

Bone marrow mesenchymal stem cells (MSCs) have been shown great potential for cardiac regeneration. However the therapeutic efficiency has become a major obstacle due to the poor survival of transplanted MSCs in ischemic cardiac tissue. Previous studies reported that melatonin could protect many different types of cells from apoptosis under various pathological conditions. In the present study, we demonstrated that melatonin, an endogenously secreted indoleamine had cytoprotection from hypoxia/serum deprivation (Hy/SD)-induced cell death in MSCs. We further investigated the possible mechanism and found out that melatonin attenuated (Hy/SD)-induced cell death could be via effectively reducing the generation of intracellular reactive oxygen species, an increase in the ratio of Bax/Bcl-2, loss of mitochondrial membrane potential and then activation of caspase-3 in MSCs in response to Hy/SD exposure. Furthermore, melatonin pretreatment significantly modulated the expression of phospho-P38MAPK and phospho-ERK1/2 in Hy/SD-induced MSCs and the protective effects of melatonin were partially reversed by ERK1/2 inhibitor but not p38 inhibitor, suggesting that melatonin inhibited Hy/SD-induced MSCs cell death through the MAPK signaling pathway in part. Taken together, the findings imply that melatonin could improve the survival of engrafted MSCs under hypoxia and serum deprivation condition. Our findings indicate that combination therapy with melatonin may provide therapeutic benefit for improving myocardial function after infarction.

Granulocyte colony-stimulating factor improves neuron survival in experimental spinal cord injury by regulating nucleophosmin-1 expression.

Granulocyte colony-stimulating factor (G-CSF) and its related mechanisms were investigated to assess the potential for this factor to exert neuroprotective effects against spinal cord injury in mice. Recombinant human granulocyte colony-stimulating factor (rhG-CSF) was injected into mice spinal cord hemisection models. Locomotor activity was assessed by using the Basso-Bettie-Bresnahan scale. Neurons isolated from spinal cords were cultured in vitro and used in a neuronal mechanical injury model. Three treatment groups were compared with this model, 1) G-CSF, 2) G-CSF + NSC348884 (a nucleophosmin 1-specific inhibitor), and 3) NSC348884. Immunofluorescence staining and Western blotting were performed to analyze the expression of G-CSF and nucleophosmin 1 (Npm1). TUNEL staining was performed to analyze apoptosis after G-CSF treatment. We found that the G-CSF receptor (G-CSFR) and Npm1 were expressed in neurons and that Npm1 expression was induced after G-CSF treatment. G-CSF inhibited neuronal apoptosis. NSC348884 induced p53-dependent cell apoptosis and partially blocked the neuroprotective activity of G-CSF on neurons in vitro. G-CSF promoted locomotor recovery and demonstrated neuroprotective effects in an acute spinal cord injury model. The mechanism of G-CSF's neuroprotection may be related in part to attenuating neuronal apoptosis by NPM1.

Analysis of gene expression profiles associated with functional recovery after spinal cord injury caused by sema4D knockdown in oligodendrocytes.

We previously showed that sema4D Knockdown in oligodendrocytes promotes functional recovery after spinal cord injury. In this paper, we examined gene expression profiles associated with functional recovery by PCR array. For general observation during first 4 weeks, we found that sema4D knockdown could reduce edema and stimulate SCEP. Further, PCR array analysis indicated sema4D knockdown in OPCs inhibited wound tissue angiogenesis and inflammation genes expression and upregulated axon regeneration genes expression at early phase. Our findings provided the molecular mechanism for its potential application.

Toxoplasma gondii: immune response and protective efficacy induced by ROP16/GRA7 multicomponent DNA vaccine with a genetic adjuvant B7-2.

Toxoplasma gondii infection occurs commonly in humans and other warm-blooded animals. Its serious impact on public health and livestock sectors makes the development of an effective vaccine particularly important. In the current study, we constructed a multiantigenic DNA vaccine expressing ROP16 and GRA7 of T. gondii and evaluated the protective efficacy of these two fragments with or without a plasmid encoding murine costimulatory molecule B7-2. These recombinant eukaryotic expression plasmids were termed pROP16, pGRA7, pROP16-GRA7 and pB7-2, respectively. After intramuscular immunization in Kunming mice, we assessed the immune response using cytokine and antibody determinations, T lymphocyte subsets analysis, and the survival times of mice post acute T. gondii challenge. The results showed that mice immunized with the multiantigenic DNA vaccine pROP16-GRA7 gained higher levels of IgG titers and IgG2a subclass titers, production of IFN-γ, percentage of CD8+ T cells and median survival times against the acute infection of T. gondii compared with those of mice administered with pROP16 or pGRA7 and those in control groups. Moreover, the adjuvant pB7-2 formulated with DNA vaccine boosted these humoral and cellular (Th1, CD8+ T cell) immune responses. Therefore, it might be a promising genetic adjuvant to DNA vaccine against T. gondii for further investigation.

Protective effect of melatonin on bone marrow mesenchymal stem cells against hydrogen peroxide-induced apoptosis in vitro.

Bone marrow mesenchymal stem cells (MSCs) transplantation has shown great promises for treating various central nervous system (CNS) diseases. However, poor viability of transplanted MSCs in injured CNS has limited the therapeutic efficiency. Oxidative stress is one of major mechanisms underlying the pathogenesis of CNS diseases and has a negative impact on the survival of transplanted MSCs. Melatonin has recently been reported to have the antioxidant and anti-apoptotic properties in serial of cells. This study was designed to investigate the protective effect and potential mechanisms of melatonin against hydrogen peroxide (H2O2)-induced apoptosis of MSCs. MSCs were pretreated with melatonin (1, 10, and 100 nM, respectively) for 30 min, followed by exposure to 400 µM H2O2 and melatonin together for 12 h. The present study reports that melatonin pretreatment significantly attenuated H2O2-induced MSC apoptosis in a dose-dependent manner. Consistently, melatonin effectively suppressed the generation of intracellular ROS, expression ratio of Bax/Bcl-2, activation of caspase-3 and expression of phospho-P38MAPK in H2O2-induced MSCs. Luzindole, a nonselective melatonin receptor antagonist, significantly counteracted melatonin's promotion effect on cell survival, indicating that melatonin exerts its protective effect on MSCs, at least in part, through the activation of melatonin receptors. The findings suggest that melatonin may be an effectively protective agent against oxidative stress-induced MSC apoptosis.