ClC-3 deficiency protects preadipocytes against apoptosis induced by palmitate in vitro and in type 2 diabetes mice

Type 2 diabetes microenvironment promotes the development of Parkinson's disease by activating microglial cell inflammation

Objective

Parkinson's disease (PD) is the second most common neurodegenerative disease in the world, and type 2 diabetes (T2DM) and PD are influenced by common genetic and environmental factors. Mitochondrial dysfunction and inflammation are common pathogenic mechanisms of both diseases. However, the close association between PD and T2DM and the specific relationship between them are not yet clear. This study aimed to reveal the specific connection between the two diseases by establishing a mouse model of comorbid PD and T2DM, as well as a Bv2 cell model.

Methods

C57BL/6 mouse were used to construct a model of PD with T2DM using streptozotocin and rotenone, while Bv2 cells were used to simulate the microenvironment of PD and T2DM using rotenone and palmitate. Behavioral tests were conducted to assess any differences in motor and cognitive functions in mouse. Immunohistochemistry was used to analyze the number of dopaminergic neurons in the substantia nigra region of mouse. Western blotting was used to detect the expression levels of TH, P-NFκB, NFκB, Cyclic GMP-AMP synthase (cGAS), and Stimulator of interferon genes (STING) proteins in the substantia nigra region of mouse and Bv2 cells. qRT-PCR was used to analyze the expression levels of IL1β, IL6, and TNF-α. Seahorse technology was used to assess mitochondrial function in Bv2 cells.

Results

T2DM exacerbated the motor and cognitive symptoms in mouse with PD. This effect may be mediated by disrupting mitochondrial function in microglial cells, leading to damaged mtDNA leakage into the cytoplasm, subsequently activating the cGAS-STING pathway and downstream P-NFκB/NFκB proteins, triggering an inflammatory response in microglial cells. Microglial cells release inflammatory factors such as IL1β, IL6, and TNF-α, exacerbating neuronal damage caused by PD.

Conclusion

Our study results suggest that T2DM may exacerbate the progression of PD by damaging mitochondrial function, and activating microglial cell inflammation. The detrimental effects on Parkinson's disease may be achieved through the activating of the cGAS-STING protein pathway.

Epigenetic and transcriptomic alterations in the ClC-3-deficient mice consuming a normal diet

Introduction: Metabolic disorders are an important health concern that threatens life and burdens society severely. ClC-3 is a member of the chloride voltage-gated channel family, and ClC-3 deletion improved the phenotypes of dysglycemic metabolism and the impairment of insulin sensitivity. However, the effects of a healthy diet on transcriptome and epigenetics in ClC-3^-/- mice were not explained in detail. Methods: Here, we performed transcriptome sequencing and Reduced Representation Bisulfite Sequencing for the liver of 3 weeks old WT and ClC-3^-/- mice consuming a normal diet to insight into the epigenetic and transcriptomic alterations of ClC-3 deficient mice. Results: In the present study, we found that ClC-3^-/- mice that were younger than 8 weeks old had smaller bodies compared to ClC-3^+/+ mice with ad libitum self-feeding normal diet, and ClC-3^-/- mice that were older than 10 weeks old had a similar body weight. Except for the spleen, lung, and kidney, the average weight of the heart, liver, and brain in ClC-3^-/- mice was lower than that in ClC-3^+/+ mice. TG, TC, HDL, and LDL in fasting ClC-3^-/- mice were not significantly different from those in ClC-3^+/+ mice. Fasting blood glucose in ClC-3^-/- mice was lower than that in ClC-3^+/+ mice; the glucose tolerance test indicated the response to blood glucose increasing for ClC-3^-/- mice was torpid, but the efficiency of lowering blood glucose was much higher once started. Transcriptomic sequencing and reduced representation bisulfite sequencing for the liver of unweaned mice indicated that ClC-3 deletion significantly changed transcriptional expression and DNA methylation levels of glucose metabolism-related genes. A total of 92 genes were intersected between DEGs and DMRs-targeted genes, of which Nos3, Pik3r1, Socs1, and Acly were gathered in type II diabetes mellitus, insulin resistance, and metabolic pathways. Moreover, Pik3r1 and Acly expressions were obviously correlated with DNA methylation levels, not Nos3 and Socs1. However, the transcriptional levels of these four genes were not different between ClC-3^-/- and ClC-3^+/+ mice at the age of 12 weeks. Discussion: ClC-3 influenced the methylated modification to regulate glucose metabolism, of which the gene expressions could be driven to change again by a personalized diet-style intervention.

Knockdown of CLC-3 may improve cognitive impairment caused by diabetic encephalopathy

BACKGROUND

Diabetic encephalopathy(DE) is a neurological complication of diabetes, and its pathogenesis is unclear. Current studies indicate that insulin receptors and downstream signaling pathways play a key role in the occurrence and development of DE. Additionally, CLC-3, a member of the CLC family of anion channels and transporters, is closely related to the secretion and processing of insulin. Here, we investigated the changes and putative roles of CLC-3 in diabetic encephalopathy.

RESULTS

To this aim, we combined lentivirus and adeno-associated virus gene transfer to change the expression level of CLC-3 in the HT-22 hippocampal cell line and hippocampal CA1. We studied the role of CLC-3 in DE through the Morris water maze test.CLC-3 expression increased significantly in HT-22 cells cultured with high glucose and STZ-induced DE model hippocampus. Moreover, Insulin receptor(IR) and downstream PI3K/AKT/GSK3β signaling pathways were also dysfunctional. After knocking down CLC-3, impaired cell proliferation, apoptosis, IR and the downstream PI3K/AKT/GSK3β signaling pathways were significantly improved. However, when CLC-3 was overexpressed, the neurotoxicity induced by high glucose was further aggravated. Rescue experiments found that through the use of inhibitors such as GSK3β, the PI3K/AKT/GSK3β signaling pathways pathway changes with the use of inhibition, and the expression of related downstream signaling molecules such as Tau and p-Tau also changes accordingly. Using adeno-associated virus gene transfer to knock down CLC-3 in the hippocampal CA1 of the DE model, the IR caused by DE and the dysfunction of the downstream PI3K/AKT/GSK3β signaling pathway were significantly improved. In addition, the impaired spatial recognition of DE was partially restored.

CONCLUSION

Our study proposes that CLC-3, as a key molecule, may regulate insulin receptor signaling and downstream PI3K/AKT/GSK3β signaling pathways and affect the pathogenesis of diabetic encephalopathy.

Clues and new evidences in arterial hypertension: unmasking the role of the chloride anion

The present review will focus on the role of chloride anion in cardiovascular disease, with special emphasis in the development of hypertensive disease and vascular inflammation. It is known that acute and chronic overload of sodium chloride increase blood pressure and have pro-inflammatory and pro-fibrotic effects on different target organs, but it is unknown how chloride may influence these processes. Chloride anion is the predominant anion in the extracellular fluid and its intracellular concentration is dynamically regulated. As the queen of the electrolytes, it is of crucial importance to understand the physiological mechanisms that regulate the cellular handling of this anion including the different transporters and cellular chloride channels, which exert a variety of functions, such as regulation of cellular proliferation, differentiation, migration, apoptosis, intracellular pH and cellular redox state. In this article, we will also review the relationship between dietary, serum and intracellular chloride and how these different sources of chloride in the organism are affected in hypertension and their impact on cardiovascular disease. Additionally, we will discuss the approach of potential strategies that affect chloride handling and its potential effect on cardiovascular system, including pharmacological blockade of chloride channels and non-pharmacological interventions by replacing chloride by another anion.

ClC-3: A Novel Promising Therapeutic Target for Atherosclerosis

Chloride channel 3 (ClC-3), a Cl^-/H⁺ antiporter, has been well established as a member of volume-regulated chloride channels (VRCCs). ClC-3 may be a crucial mediator for activating inflammation-associated signaling pathways by regulating protein phosphorylation. A growing number of studies have indicated that ClC-3 overexpression plays a crucial role in mediating increased plasma low-density lipoprotein levels, vascular endothelium dysfunction, pro-inflammatory activation of macrophages, hyper-proliferation and hyper-migration of vascular smooth muscle cells (VSMCs), as well as oxidative stress and foam cell formation, which are the main factors responsible for atherosclerotic plaque formation in the arterial wall. In the present review, we summarize the molecular structures and classical functions of ClC-3. We further discuss its emerging role in the atherosclerotic process. In conclusion, we explore the potential role of ClC-3 as a therapeutic target for atherosclerosis.

Islet isograft transplantation improves insulin sensitivity in a murine model of type 2 diabetes

PURPOSE

Type 2 diabetes develops in the presence of chronic overnutrition and genetic susceptibility, and causes insulin resistance and relative insulin deficiency. We hypothesized that islet transplantation can improve insulin sensitivity by modifying the mediators of insulin sensitivity in the pancreas, liver, muscle, and adipose tissues.

METHODS

Eight-week-old male mice were used as both recipients and donors in this study. To induce type 2 diabetes with partial β-cell failure, the mice were fed a high-fat diet for 4 weeks and then injected with low-dose streptozotocin. Approximately 400 islet cells from a donor mouse were injected into the renal capsule of a recipient mouse for islet transplantation. After 6 weeks following transplantation, the mediators of insulin sensitivity in the pancreas, liver, muscle, and adipose tissues were quantitatively compared between islet-transplanted and non-transplanted groups.

RESULTS

Intravenous glucose tolerance test showed that whereas the non-transplanted mice failed to show notable reductions in the glucose level, the islet-transplanted mice showed significant reductions in the serum glucose level to ~200 mg/dL at 6 weeks after islet transplantation. The islet-transplanted mice showed significantly higher Matsuda index and significantly lower HOMA-IR than did the non-transplanted mice, thus signifying improved insulin sensitivity.

CONCLUSIONS

Islet transplantation resulted in improvements in multiple indices of insulin sensitivity in a murine model of type 2 diabetes. Islet transplantation may be utilized to improve insulin sensitivity in patients with type 2 diabetes.

5‑Nitro‑2‑(3‑phenylpropylamino) benzoic acid induces apoptosis of human lens epithelial cells via reactive oxygen species and endoplasmic reticulum stress through the mitochondrial apoptosis pathway

Cataracts have a high incidence and prevalence rate worldwide, and they are the leading cause of blindness. Lens epithelial cell (LEC) apoptosis is often analysed in cataract research since it is the pathological basis of cataracts, except for congenital cataract. Chloride channels are present in ocular tissues, such as in trabecular cells, LECs and other cells. They serve an important role in apoptosis and participate in endoplasmic reticulum (ER) stress and oxidative stress. However, their role in the apoptosis of LECs has not been discussed. The present study examined the effects of the chloride channel blocker 5‑nitro‑2‑(3‑phenylpropylamino) benzoic acid (NPPB) in human LECs (HLECs) to elucidate the role of NPPB in HLECs and investigate the role and mechanism of chloride channels in cataract formation. HLECs were exposed to NPPB. Cell survival rate was evaluated using Cell Counting Kit‑8 assays. Oxidative stress was detected as reactive oxygen species (ROS) in cells by using a ROS assay kit. Apoptosis was examined by assessing mitochondrial membrane potential and using a JC‑1 assay kit, and western blot analysis was performed to measure the expression levels of mitochondrial‑dependent apoptosis pathway‑associated proteins. ER stress was evaluated by determining the intracellular calcium ion fluorescence intensity, and western blot analysis was performed to measure ER stress‑associated protein expression. The results revealed that NPPB treatment decreased the viability of HLECs and increased apoptosis. Additionally, NPPB increased intracellular ROS levels, as well as the number of JC‑1 monomers and the protein expression levels of B‑cell lymphoma‑2 (Bcl‑2)‑associated X and cleaved caspase‑3, and decreased Bcl‑2 protein expression. NPPB increased intracellular calcium ions, the protein expression levels of activating transcription factor 6, JNK, C/EBP homologous protein and caspase‑12, and the phosphorylation of protein kinase R‑like endoplasmic reticulum kinase. N‑acetylcysteine and 4‑phenylbutyric acid inhibited NPPB‑induced oxidative stress, ER stress and apoptosis. Therefore, NPPB treatment decreased cell viability and promoted apoptosis of HLECs via the promotion of oxidative and ER stress.

Clcn3 deficiency ameliorates high-fat diet-induced obesity and adipose tissue macrophage inflammation in mice

Obesity induces accumulation of adipose tissue macrophages (ATMs) and ATM-driven inflammatory responses that promote the development of glucose and lipid metabolism disorders. ClC-3 chloride channel/antiporter, encoded by the Clcn3, is critical for some basic cellular functions. Our previous work has shown significant alleviation of type 2 diabetes in Clcn3 knockout (Clcn3^−/−) mice. In the present study we investigated the role of Clcn3 in high-fat diet (HFD)-induced obesity and ATM inflammation. To establish the mouse obesity model, both Clcn3^−/− mice and wild-type mice were fed a HFD for 4 or 16 weeks. The metabolic parameters were assessed and the abdominal total adipose tissue was scanned using computed tomography. Their epididymal fat pad tissue and adipose tissue stromal vascular fraction (SVF) cells were isolated for analyses. We found that the HFD-fed Clcn3^−/− mice displayed a significant decrease in obesity-induced body weight gain and abdominal visceral fat accumulation as well as an improvement of glucose and lipid metabolism as compared with HFD-fed wild-type mice. Furthermore, the Clcn3 deficiency significantly attenuated HFD-induced ATM accumulation, HFD-increased F4/80⁺ CD11c⁺ CD206⁻ SVF cells as well as HFD-activated TLR-4/NF-κB signaling in epididymal fat tissue. In cultured human THP-1 macrophages, adenovirus-mediated transfer of Clcn3 specific shRNA inhibited, whereas adenovirus-mediated cDNA overexpression of Clcn3 enhanced lipopolysaccharide-induced activation of NF-κB and TLR-4. These results demonstrate a novel role for Clcn3 in HFD-induced obesity and ATM inflammation.

ClC-3 promotes angiotensin II-induced reactive oxygen species production in endothelial cells by facilitating Nox2 NADPH oxidase complex formation

Recent evidence suggests that ClC-3, a member of the ClC family of Cl^- channels or Cl^-/H⁺ antiporters, plays a critical role in NADPH oxidase-derived reactive oxygen species (ROS) generation. However, the underling mechanisms remain unclear. In this study we investigated the effects and mechanisms of ClC-3 on NADPH oxidase activation and ROS generation in endothelial cells. Treatment with angiotensin II (Ang II, 1 μmol/L) significantly elevated ClC-3 expression in cultured human umbilical vein endothelial cells (HUVECs). Furthermore, Ang II treatment increased ROS production and NADPH oxidase activity, an effect that could be significantly inhibited by knockdown of ClC-3, and further enhanced by overexpression of ClC-3. SA-β-galactosidase staining showed that ClC-3 silencing abolished Ang II-induced HUVEC senescence, whereas ClC-3 overexpression caused the opposite effects. We further showed that Ang II treatment increased the translocation of p47phox and p67phox from the cytosol to membrane, accompanied by elevated Nox2 and p22phox expression, which was significantly attenuated by knockdown of ClC-3 and potentiated by overexpression of ClC-3. Moreover, overexpression of ClC-3 increased Ang II-induced phosphorylation of p47phox and p38 MAPK in HUVECs. Pretreatment with a p38 inhibitor SB203580 abolished ClC-3 overexpression-induced increase in p47phox phosphorylation, as well as NADPH oxidase activity and ROS generation. Our results demonstrate that ClC-3 acts as a positive regulator of Ang II-induced NADPH oxidase activation and ROS production in endothelial cells, possibly via promoting both Nox2/p22phox expression and p38 MAPK-dependent p47phox/p67phox membrane translocation, then increasing Nox2 NADPH oxidase complex formation.

Opening of the CLC-3 chloride channel induced by dihydroartemisinin contributed to early apoptotic events in human poorly differentiated nasopharyngeal carcinoma cells

Nasopharyngeal carcinoma (NPC) is a specific type of head and neck cancer that is prevalent in Southeast Asia. Dihydroartemisinin (DHA), a semisynthetic derivative of artemisinin, has specific anticancer activity. Here, we aimed to investigate the role of the CLC-3 chloride channel in the anticancer effect of DHA in poorly differentiated NPC CNE-2Z cells. First, we observed that DHA could specifically inhibit the proliferation, induce apoptosis, and increase cleaved caspase-3 expression in the CNE-2Z cells. Then, we found that DHA could activate chloride channels, which led to Cl^- efflux and apoptotic volume decrease (AVD) in the early stage in the CNE-2Z cells. DHA also specifically increased CLC-3 chloride channel protein expression in the CNE-2Z cells. Silencing of the CLC-3 protein expression depleted the Cl^- currents, and decreased the AVD capacity and cell apoptosis induced by DHA. Finally, we revealed that the [Ca²⁺ ]_i increased after around 6 hours of treatment with DHA, which was also inhibited by silencing of the CLC-3 protein expression. Our data demonstrated that the selective antitumor activities of DHA in NPC may occur through the specific activation of the CLC-3 Cl^- channel, leading to Cl^- efflux, and induced AVD, then led to [Ca²⁺ ]_i accumulation and caspase-3 activation, and finally induced apoptosis. The activation of the CLC-3 chloride channel played an essential and proximal upstream role in the antitumor activities of DHA.

Knockdown of Chloride Channel-3 Inhibits Breast Cancer Growth In Vitro and In Vivo

Purpose

Chloride channel-3 (ClC-3) is a member of the chloride channel family and plays a critical role in a variety of cellular activities. The aim of the present study is to explore the molecular mechanisms underlying the antitumor effect of silencing ClC-3 in breast cancer.

Methods

Human breast cancer cell lines MDA-MB-231 and MCF-7 were used in the experiments. Messenger RNA and protein expression were examined by quantitative real-time polymerase chain reaction and western blot analysis. Cell proliferation was measured by the bromodeoxyuridine method, and the cell cycle was evaluated using fluorescence-activated cell sorting. Protein interaction in cells was analyzed by co-immunoprecipitation. Tumor tissues were stained with hematoxylin-eosin and tumor burden was measured using the Metamorph software.

Results

Breast cancer tissues collected from patients showed an increase in ClC-3 expression. Knockdown of ClC-3 inhibited the secretion of insulin-like growth factor (IGF)-1, cell proliferation, and G1/S transition in breast cancer cells. In the mouse xenograft model of human breast carcinoma, tumor growth was significantly slower in animals injected with ClC-3-deficient cells compared with the growth of normal human breast cancer cells. In addition, silencing of ClC-3 attenuated the expression of proliferating cell nuclear antigen, Ki-67, cyclin D1, and cyclin E, as well as the activation of extracellular signalregulated protein kinases (ERK) 1/2, both in vitro and in vivo.

Conclusion

Together, our data suggest that upregulation of ClC-3 by IGF-1 contributes to cell proliferation and tumor growth in breast cancer, and ClC-3 deficiency suppresses cell proliferation and tumor growth via the IGF/IGF receptor/ERK pathway.

Xueshuantong injection (lyophilized) combined with salvianolate lyophilized injection protects against focal cerebral ischemia/reperfusion injury in rats through attenuation of oxidative stress

Salvianolate lyophilized injection (SLI) and Xueshuantong injection (lyophilized) (XST) are two herbal standardized preparations that have been widely used in China for the treatment of acute cerebral infarction. In this study, we investigated the neuroprotective effects of SLI combined with XST in a rat model of middle cerebral artery occlusion-reperfusion (MCAO/R). Wistar rats were subjected to 1.5 h of MCAO followed by reperfusion for 3 h, then were treated with SLI or XST alone, or with their combinations via tail vein injection daily for 3 d. Edaravone (EDI, 6 mg·kg^-1·d^-1) was used as a positive control drug, We showed that administration of a combination of 1X1S (XST 100 mg·kg^-1·d^-1 plus SLI 21 mg·kg^-1·d^-1) more effectively protected the ischemic brains than SLI or XST used alone. Administration of 1X1S not only significantly decreased neurological deficit scores and infarct volumes and increased regional cerebral blood flow, but also inhibited the activation of both microglia and astrocytes in the hippocampus. Furthermore, administration of 1X1S significantly decreased the levels of MDA and ROS with concomitant increases in the levels of antioxidant activity (SOD, CAT and GSH) in the brain tissues as compared with SLI and XST used alone. Moreover, administration of 1X1S remarkably upregulated the expression of Nrf-2, HO-1 and NQO-1, and downregulated the expression of Keap1 and facilitated the nuclear translocation of Nrf-2 in the brain tissues as compared with XST used alone. Our study demonstrates that a combination of 1X1S effectively protects MCAO/R injury via suppressing oxidative stress and the Nrf-2/Keap1 pathway.

Overexpression of chloride channel-3 predicts unfavorable prognosis and promotes cellular invasion in gastric cancer

BACKGROUND

Chloride channel-3 (CLC-3) has been reported to promote the proliferation and invasion in various tumors, yet little is known about its role in gastric cancer. In the present study, we investigated the clinical significance of CLC-3 and its biological role in gastric cancer.

METHODS

Bioinformatic analysis, immunohistochemical staining, quantitative real-time polymerase chain reaction and Western blot assay were used to assess the expression of CLC-3 and its clinical significance in gastric cancer. The biological role of CLC-3 and its underlying mechanism were detected through in vitro experiments.

RESULTS

CLC-3 was highly expressed in gastric cancer tissues and cell lines, and high levels of CLC-3 were significantly associated with adverse clinicopathological parameters and shorter overall survival time in patients with gastric cancer. Functional studies revealed that silencing of CLC-3 decreased, while overexpression promoted, the proliferation, migration and invasion of gastric cancer cells in vitro. Mechanistic studies suggested that canonical TGF-β/Smad signaling pathway is involved in CLC-3-induced gastric cancer cells proliferation, migration and invasion.

CONCLUSION

These findings indicate the vital role of CLC-3 in gastric cancer progression and its potential role of a therapeutic target for treatment.

Xyloketal B alleviates cerebral infarction and neurologic deficits in a mouse stroke model by suppressing the ROS/TLR4/NF-κB inflammatory signaling pathway

Xyloketal B (Xyl-B) is a novel marine compound isolated from mangrove fungus Xylaria sp. We previously demonstrated that pretreatment with Xyl-B exerted neuroprotective effects and attenuated hypoxic-ischemic brain injury in neonatal mice. In the present study we investigated the neuroprotective effects of pre- and post-treatment with Xyl-B in adult mice using a transient middle cerebral artery occlusion (tMCAO) model, and explored the underlying mechanisms. Adult male C57 mice were subjected to tMCAO surgery. For the pre-treatment, Xyl-B was given via multiple injections (12.5, 25, and 50 mg·kg^-1·d^-1, ip) 48 h, 24 h and 30 min before ischemia. For the post-treatment, a single dose of Xyl-B (50 mg/kg, ip) was injected at 0, 1 or 2 h after the onset of ischemia. The regional cerebral perfusion was monitored using a laser-Doppler flowmeter. TTC staining was performed to determine the brain infarction volume. We found that both pre-treatment with Xyl-B (50 mg/kg) and post-treatment with Xyl-B (50 mg/kg) significantly reduced the infarct volume, but had no significant hemodynamic effects. Treatment with Xyl-B also significantly alleviated the neurological deficits in tMCAO mice. Furthermore, treatment with Xyl-B significantly attenuated ROS overproduction in brain tissues; increased the MnSOD protein levels, suppressed TLR4, NF-κB and iNOS protein levels; and downregulated the mRNA levels of proinflammatory cytokines, including IL-1β, TNF-α, IL-6 and IFN-γ. Moreover, Xyl-B also protected blood-brain barrier integrity in tMCAO mice. In conclusion, Xyl-B administered within 2 h after the onset of stroke effectively protects against focal cerebral ischemia; the underlying mechanism may be related to suppressing the ROS/TLR4/NF-κB inflammatory signaling pathway.

ClC-3 Expression and Its Association with Hyperglycemia Induced HT22 Hippocampal Neuronal Cell Apoptosis

Although apoptosis plays an important role in the development of Diabetic Encephalopathy (DE), the underlying molecular mechanisms remain unclear. With respect to this, the present work aims to study the variation in chloride/proton exchanger ClC-3 expression and its association with HT22 hippocampal neuronal apoptosis under hyperglycemic condition in vitro. The cells were stimulated with added 0, 5, or 25 mM glucose or mannitol for up to 72 hours before assessing the rate of ClC-3 expression, cell viability, and apoptosis. In a consecutive experiment, cells received chloride channel blocker in addition to glucose. The rate of cellular death/apoptosis and viability was measured using Flow Cytometry and MTT assay, respectively. Changes in ClC-3 expression were assessed using immunofluorescence staining and western blot analysis. The results revealed a significant increase in cellular apoptosis and reduction in viability, associated with increased ClC-3 expression in high glucose group. Osmolarity had no role to play. Addition of chloride channel blocker completely abolished this effect. Thus we conclude that, with its increased expression, ClC-3 plays a major role in hyperglycemia induced hippocampal neuronal apoptosis. To strengthen our understanding of this aforesaid association, we conducted an extensive literature search which is presented in this paper.