Status epilepticus increases mature granule cells in the molecular layer of the dentate gyrus in rats

Enhanced neurogenesis in the dentate gyrus of the hippocampus following seizure activity, especially status epilepticus, is associated with ectopic residence and aberrant integration of newborn granule cells. Hilar ectopic granule cells may be detrimental to the stability of dentate circuitry by means of their electrophysiological properties and synaptic connectivity. We hypothesized that status epilepticus also increases ectopic granule cells in the molecular layer. Status epilepticus was induced in male Sprague-Dawley rats by intraperitoneal injection of pilocarpine. Immunostaining showed that many doublecortin-positive cells were present in the molecular layer and the hilus 7 days after the induction of status epilepticus. At least 10 weeks after status epilepticus, the estimated number of cells positive for both prospero homeobox protein 1 and neuron-specific nuclear protein in the hilus was significantly increased. A similar trend was also found in the molecular layer. These findings indicate that status epilepticus can increase the numbers of mature and ectopic newborn granule cells in the molecular layer.

Long-term administration of scopolamine interferes with nerve cell proliferation, differentiation and migration in adult mouse hippocampal dentate gyrus, but it does not induce cell death

Long-term administration of scopolamine, a muscarinic receptor antagonist, can inhibit the survival of newly generated cells, but its effect on the proliferation, differentiation and migration of nerve cells in the adult mouse hippocampal dentate gyrus remain poorly understood. In this study, we used immunohistochemistry and western blot methods to weekly detect the biological behaviors of nerve cells in the hippocampal dentate gyrus of adult mice that received intraperito- neal administration of scopolamine for 4 weeks. Expression of neuronal nuclear antigen （NeuN; a neuronal marker） and Fluoro-]ade B （a marker for the localization of neuronal degeneration） was also detected. After scopolamine treatment, mouse hippocampal neurons did not die, and Ki-67 （a marker for proliferating cells）-immunoreactive cells were reduced in number and reac hed the lowest level at 4 weeks. Doublecortin （DCX; a marker for newly generated neurons）-im- munoreactive cells were gradually shortened in length and reduced in number with time. After scopolamine treatment for 4 weeks, nearly all of the 5-bromo-2＇-deoxyuridine （BrdU）-labeled newly generated cells were located in the subgranular zone of the dentate gyrus, but they did not migrate into the granule cell layer. Few mature BrdU/NeuN double-labeled cells were seen in the subgranular zone of the dentate gyrus. These findings suggest that long-term administration of scopolamine interferes with the proliferation, differentiation and migration of nerve cells in the adult mouse hippocampal dentate gyrus, but it does not induce cell death.

Adult neurogenesis in the primate hippocampus

Adult hippocampal neurogenesis(AHN) is crucial for learning,memory,and emotion.Deficits of AHN may lead to reduced cognitive abilities and neurodegenerative disorders,such as Alzheimer’s disease.Extensive studies on rodent AHN have clarified the developmental and maturation processes of adult neural stem/progenitor cells.However,to what extent these findings apply to primates remains controversial.Recent advances in next-generation sequencing technologies have enabled in-depth investigation of the transcriptome of AHN-related populations at single-cell resolution.Here,we summarize studies of AHN in primates.Results suggest that neurogenesis is largely shared across species,but substantial differences also exist.Marker gene expression patterns in primates differ from those of rodents.Compared with rodents,the primate hippocampus has a higher proportion of immature dentate granule cells and a longer maturation period of newly generated granule cells.Future research on species divergence may deepen our understanding of the mechanisms underlying adult neurogenesis in primates.

Study on the Relationship between AMPK/UCP2 Pathway and Mitochondrial Dysfunction in Granulosa Cells of Polycystic Ovay Syndrome

Objective:To investigate the changes of the AMP-activated protein kinase(AMPK)/uncoupling protein 2(UCP2)(AMPK/UCP2)pathway in ovarian granulosa cells with PCOS and its relationship with mitochondrial dysfunction.Methods:PCOS mouse models and normally fed mice,ovarian granulosa cells from the two mice were extracted,and the protein expression levels of AMPKα,p-AMPKαand UCP2 were detected by western blotting.The ROS and ATP content of granulosa cells were determined by colorimetric and chemiluminescence immunoassays to assess mitochondrial function.Pearson correlation analysis was used to determine the correlation between AMPK/UCP2 pathway-related proteins,ROS and ATP.Results:P-AMPKα/GAPDH(0.12±0.09),AMPKα/GAPDH(0.35±0.40),P-AMPKα/AMPKα(0.56±0.33)and ATP(0.36±0.04)pmol/mg in PCOS model mice were lower than those in non-POCS groups,while UCP2/GAPDH(1.18±0.28)and ROS(48810.92±4498.08)were lower than those in non-POCS groups.The fluorescence intensity of DCF was higher than that of the non-POCS group(P<0.05).AMPK was positively correlated with ATP and negatively correlated with ROS.UCP2 was positively correlated with ROS and negatively correlated with ATP.Conclusion:There are abnormal changes such as decreased AMPK expression and increased UCP2 expression in ovarian granulosa cells of PCOS,and AMPK is positively and negatively correlated with mitochondrial function indexes ATP and ROS,while UCP2 is the opposite,suggesting that the imbalance in the expression and activity of AMPK/UCP2 pathway in PCOS may be one of the molecular mechanisms leading to mitochondrial dysfunction.Regulation of AMPK/UCP2 pathway activity may be a potential therapeutic target to ameliorate PCOS-related mitochondrial dysfunction.

Ligliptin for treatment of type 2 diabetes mellitus with early renal injury: Efficacy and impact on endogenous hydrogen sulfide and endothelial function

BACKGROUND Diabetes is a clinically common chronic disease,and its incidence has been increasing in recent years.Diabetes is believed to accelerate the process of atherosclerosis in patients,and abnormal endothelial function is an important factor leading to diabetic kidney damage.AIM To investigate the efficacy of ligliptin in the treatment of type 2 diabetes mellitus(T2DM)with early renal injury and its effect on serum endogenous hydrogen sulfide(H2S),endothelial cell particles,and endothelial function.METHODS From January 2018 to April 2019,110 patients with T2DM and early kidney injury treated at our hospital were divided into an observation group(receiving ligliptin treatment,n=54)and a control group(receiving gliquidone therapy,n=56).Blood glucose and renal function before and after treatment were compared between the two groups.RESULTS The differences in fasting blood glucose,2 h blood glucose,and glycated hemoglobin were not statistically significant between the two groups after treatment.The urinary albumin excretion rate after treatment in the ligliptin group was 70.32±11.21μg/min,which was significantly lower than that of the gliquidone group(P=0.000).Serum endogenous H2S and endothelial cell microparticles of the ligliptin treatment group were 40.04±8.82 mol/L and 133.40±34.39,respectively,which were significantly lower than those of the gliquidone treatment group(P=0.000 for both);endothelin-dependent diastolic function and nitric oxide after treatment in the ligliptin group were 7.98%±1.22%and 190.78±30.32 mol/L,significantly higher than those of the gliquidone treatment group(P=0.000 for both).CONCLUSION Ligliptin treatment of T2DM with early renal injury has the same glucoselowering effect as gliquidone treatment.Ligliptin treatment has a better effect and it can significantly improve the renal function and vascular endothelial function of patients,and reduce serum endogenous H2S and endothelial cell particle levels.

The Joubert Syndrome Gene arl13b is Critical for Early Cerebellar Development in Zebrafish

Joubert syndrome is characterized by unique malformation of the cerebellar vermis.More than thirty Joubert syndrome genes have been identified,including ARL13 B.However,its role in cerebellar development remains unexplored.We found that knockdown or knockout of arl13b impaired balance and locomotion in zebrafish larvae.Granule cells were selectively reduced in the corpus cerebelli,a structure homologous to the mammalian vermis.Purkinje cell progenitors were also selectively disturbed dorsomedially.The expression of atoh1 and ptf1,proneural genes of granule and Purkinje cells,respectively,were selectively down-regulated along the dorsal midline of the cerebellum.Moreover,wnt1,which is transiently expressed early in cerebellar development,was selectively reduced.Intriguingly,activating Wnt signaling partially rescued the granule cell defects in arl13b mutants.These findings suggested that Arl13 b is necessary for the early development of cerebellar granule and Purkinje cells.The arl13b-deficient zebrafish can serve as a model organism for studying Joubert syndrome.

FOXG1 Directly Suppresses Wnt5a During the Development of the Hippocampus

The Wnt signaling pathway plays key roles in various developmental processes.Wnt5a,which activates the non-canonical pathway,has been shown to be particularly important for axon guidance and outgrowth as well as dendrite morphogenesis.However,the mechanism underlying the regulation of Wnt5a remains unclear.Here,through conditional disruption of Foxg1 in hippocampal progenitors and postmitotic neurons achieved by crossing Foxg1~(fl/fl)with Emx1-Cre and Nex-Cre,respectively,we found that Wnt5a rather than Wnt3a/Wnt2b was markedly upregulated.Overexpression of Foxg1 had the opposite effects along with decreased dendritic complexity and reduced mossy fibers in the hippocampus.We further demonstrated that FOXG1 directly repressed Wnt5a by binding to its promoter and one enhancer site.These results expand our knowledge of the interaction between Foxg1 and Wnt signaling and help elucidate the mechanisms underlying hippocampal development.

Development of glutamatergic innervation during maturation of adult-born neurons

The dentate gyrus is the entrance of the hippocampal formation and a primary target of excitatory afferents from the entorhinal cortex that carry spatial and sensory information. Mounting evidence suggests that continual adult neurogenesis contributes to appropriate processing of cortical information. The ongoing integration of adult born neurons dynamically modulates connectivity of the network, potentially contributing to dentate cognitive function. Here we review the current understanding of how glutamatergie innervation develops during the progression of adult-born neuron maturation. Summarizing the developmental stages of dentate neurogenesis, we also demonstrate that new neurons at an immature stage of maturation begin to process afferent activity from both medial and lateral entorhinal cortices.