Insulin reduces endoplasmic reticulum stress-induced apoptosis by decreasing mitochondrial hyperpolarization and caspase-12 in INS-1 pancreatic ß-cells.

Pancreatic ß-cell mass is a critical determinant of insulin secretion. Severe endoplasmic reticulum (ER) stress causes ß-cell apoptosis; however, the mechanisms of progression and suppression are not yet fully understood. Here, we report that the autocrine/paracrine function of insulin reduces ER stress-induced ß-cell apoptosis. Insulin reduced the ER-stress inducer tunicamycin- and thapsigargin-induced cell viability loss due to apoptosis in INS-1 ß-cells. Moreover, the effect of insulin was greater than that of insulin-like growth factor-1 at physiologically relevant concentrations. Insulin did not attenuate the ER stress-induced increase in unfolded protein response genes. ER stress did not induce cytochrome c release from mitochondria. Mitochondrial hyperpolarization was induced by ER stress and prevented by insulin. The protonophore/mitochondrial oxidative phosphorylation uncoupler, but not the antioxidants N-acetylcysteine and α-tocopherol, exhibited potential cytoprotection during ER stress. Both procaspase-12 and cleaved caspase-12 levels increased under ER stress. The caspase-12 inhibitor Z-ATAD-FMK decreased ER stress-induced apoptosis. Caspase-12 overexpression reduced cell viability, which was diminished in the presence of insulin. Insulin decreased caspase-12 levels at the post-translational stages. These results demonstrate that insulin protects against ER stress-induced ß-cell apoptosis in this cell line. Furthermore, mitochondrial hyperpolarization and increased caspase-12 levels are involved in ER stress-induced and insulin-suppressed ß-cell apoptosis.

IL-17A exacerbates caspase-12-dependent neuronal apoptosis following ischemia through the Src-PLCγ-calpain pathway.

Interleukin-17 A (IL-17 A) contributes to inflammation and causes secondary injury in post-stroke patients. However, little is known regarding the mechanisms that IL-17 A is implicated in the processes of neuronal death during ischemia. In this study, the mouse models of middle cerebral artery occlusion/reperfusion (MCAO/R)-induced ischemic stroke and oxygen-glucose deprivation/reoxygenation (OGD/R)-simulated in vitro ischemia in neurons were employed to explore the role of IL-17 A in promoting neuronal apoptosis. Mechanistically, endoplasmic reticulum stress (ERS)-induced neuronal apoptosis was accelerated by IL-17 A activation through the caspase-12-dependent pathway. Blocking calpain or phospholipase Cγ (PLCγ) inhibited IL-17 A-mediated neuronal apoptosis under ERS by inhibiting caspase-12 cleavage. Src and IL-17 A are linked, and PLCγ directly binds to activated Src. This binding causes intracellular Ca2+ flux and activates the calpain-caspase-12 cascade in neurons. The neurological scores showed that intracerebroventricular (ICV) injection of an IL-17 A neutralizing mAb decreased the severity of I/R-induced brain injury and suppressed apoptosis in MCAO mice. Our findings reveal that IL-17 A increases caspase-12-mediated neuronal apoptosis, and IL-17 A suppression may have therapeutic potential for ischemic stroke.

Influence of trimetazidine on myocardial injury in mice with diabetic cardiomyopathy.

INTRODUCTION: The prevalence of diabetes mellitus is increasing year by year globally, and diabetic cardiomyopathy (DCM), as the most common complication of type 2 diabetes mellitus, seriously affects the prognosis of patients. Trimetazidine (TMZ), as a drug affecting myocardial energy metabolism, mainly reduces the oxidation rate of ß-oxidation by inhibiting 3-ketoacyl-CoA thiolase (3-KAT), a key enzyme in ß-oxidation of free fatty acid (FFA), so that the energy metabolism substrate of cardiomyocytes preferentially selects glucose rather than fatty acids, increases the content of intracellular adenosine triphosphate (ATP), enhances the contractile function of cardiomyocytes, and improves the state of cellular ischemia and hypoxia. Previous studies have shown that TMZ is closely related to the activation and induction of apoptosis of the MAPK pathway and AMPK pathway, and plays a role in the treatment of diabetic cardiomyopathy, but the specific mechanism is still unclear. OBJECTIVE: This study aims to investigate the impact of TMZ on myocardial damage in mice exhibiting diabetic cardiomyopathy (DCM), and to furnish a laboratory foundation for the clinical treatment of diabetic cardiomyopathy. METHOD: Male db/db mice (6 weeks old, n = 21) and male wild-type (wt) (6 weeks old, n = 20) mice were selected for the study. The wt mice were randomly assigned to the wt group (n = 10) and wt + TMZ group (n = 10), while the remaining db/db mice were randomly allocated to the db/db group (n = 11) and db/db + TMZ group (n = 10). Following 8 weeks of feeding, the wt + TMZ group and db/db + TMZ group received TMZ via gavage, whereas the remaining groups were administered physiological saline. Periodic measurements of blood glucose, blood lipids, and myocardial enzymes were conducted in mice, with samples obtained after the 12th week for subsequent biochemical analysis, myocardial pathology assessment, immunohistochemistry, western blot analysis, and TUNEL staining (TdT-mediated dUTP Nick-End Labeling). RESULT: GLU, TC, TG, LDL-C, and CK-MB levels were significantly higher in db/db mice compared to wt mice (GLU: M ± SD wt 5.94 ± 0.37, db/db 17.63 ± 0.89, p < 0.05, ES = 0.991; TC: M ± SD wt 3.01 ± 0.32, db/db 6.97 ± 0.36, p < 0.05, ES = 0.972; TG: M ± SD wt 0.58 ± 0.2, db/db 1.75 ± 0.14, p < 0.05, ES = 0.920; LDL-C: M ± SD wt 1.59 ± 0.12, db/db 3.87 ± 0.14, p < 0.05, ES = 0.989; CK-MB: M ± SD wt 0.12 ± 0.01, db/db 0.31 ± 0.04, p < 0.05, ES = 0.928). HDL-C levels were significantly lower in db/db mice (M ± SD wt 1.89 ± 0.08, db/db 0.64 ± 0.09, p < 0.05, ES = 0.963). Histopathological analysis confirmed myocardial damage in db/db mice. Treatment with TMZ reduced GLU, TC, TG, LDL-C, and CK-MB levels (p < 0.05, ES > 0.9) and increased HDL-C levels compared to untreated db/db mice. Additionally, TMZ treatment significantly decreased myocardial cell apoptosis (p < 0.05, ES = 0.980). These results demonstrate the efficacy of TMZ in reversing myocardial injury in DCM mice. CONCLUSION: TMZ can mitigate myocardial damage in db/db mice by downregulating the expression of caspase-12, a protein associated with the endoplasmic reticulum stress (ERS) cell apoptosis pathway, consequently diminishing cell apoptosis. This underscores the protective efficacy of TMZ against myocardial damage in mice afflicted with DCM.

The Preventive Effects of Salubrinal against Pyrethroid-Induced Disruption of Adult Hippocampal Neurogenesis in Mice.

Environmental factors, including pesticide exposure, have been identified as substantial contributors to neurodegeneration and cognitive impairments. Previously, we demonstrated that repeated exposure to deltamethrin induces endoplasmic reticulum (ER) stress, reduces hippocampal neurogenesis, and impairs cognition in adult mice. Here, we investigated the potential relationship between ER stress and hippocampal neurogenesis following exposure to deltamethrin, utilizing both pharmacological and genetic approaches. To investigate whether ER stress is associated with inhibition of neurogenesis, mice were given two intraperitoneal injections of eIf2α inhibitor salubrinal (1 mg/kg) at 24 h and 30 min prior to the oral administration of deltamethrin (3 mg/kg). Salubrinal prevented hippocampal ER stress, as indicated by decreased levels of C/EBP-homologous protein (CHOP) and transcription factor 4 (ATF4) and attenuated deltamethrin-induced reductions in BrdU-, Ki-67-, and DCX-positive cells in the dentate gyrus (DG) of the hippocampus. To further explore the relationship between ER stress and adult neurogenesis, we used caspase-12 knockout (KO) mice. The caspase-12 KO mice exhibited significant protection against deltamethrin-induced reduction of BrdU-, Ki-67-, and DCX-positive cells in the hippocampus. In addition, deltamethrin exposure led to a notable upregulation of CHOP and caspase-12 expression in a significant portion of BrdU- and Ki-67-positive cells in WT mice. Conversely, both salubrinal-treated mice and caspase-12 KO mice exhibited a considerably lower number of CHOP-positive cells in the hippocampus. Together, these findings suggest that exposure to the insecticide deltamethrin triggers ER stress-mediated suppression of adult hippocampal neurogenesis, which may subsequently contribute to learning and memory deficits in mice.

Valproate reduces retinal ganglion cell apoptosis in rats after optic nerve crush.

The retinal ganglion cells of the optic nerve have a limited capacity for self-repair after injury. Valproate is a histone deacetylase inhibitor and multitarget drug, which has been demonstrated to protect retinal neurons. In this study, we established rat models of optic nerve-crush injury and injected valproate into the vitreous cavity immediately after modeling. We evaluated changes in the ultrastructure morphology of the endoplasmic reticulum of retinal ganglion cells over time via transmission electron microscope. Immunohistochemistry and western blot assay revealed that valproate upregulated the expression of the endoplasmic reticulum stress marker glucose-regulated protein 78 and downregulated the expression of transcription factor C/EBP homologous protein, phosphorylated eukaryotic translation initiation factor 2α, and caspase-12 in the endoplasmic reticulum of retinal ganglion cells. These findings suggest that valproate reduces apoptosis of retinal ganglion cells in the rat after optic nerve-crush injury by attenuating phosphorylated eukaryotic translation initiation factor 2α-C/EBP homologous protein signaling and caspase-12 activation during endoplasmic reticulum stress. These findings represent a newly discovered mechanism that regulates how valproate protects neurons.

Cigarette smoking induces the activation of RIP2/caspase-12/NF-κB axis in oral squamous cell carcinoma.

Cigarette smoking is one of the major risk factors for the occurrence and progression of oral squamous cell carcinoma (OSCC). Receptor-interacting protein 2 (RIP2) has been involved in mucosal immunity and homeostasis via a positive regulation of nuclear factor κB (NF-κB) transcription factor activity. Caspase-12 can bind to RIP2 and dampen mucosal immunity. However, the roles of RIP2/NF-κB and caspase-12 in OSCC induced by cigarette smoking remain unknown. Herein, we investigated the effects of cigarette smoking on the RIP2/NF-κB and caspase-12 in human OSCC tissues and OSCC cell lines (HSC-3). We first observed that RIP2 mediated NF-κB activation and caspase-12 upregulation in OSCC patients with cigarette smoking and cigarette smoke extract (CSE)-treated HSC-3 cells, respectively. Moreover, we confirmed that the downregulation of RIP2 by siRNA resulted in the reduction of caspase-12 expression and NF-κB activity in the presence of CSE treatment in vitro. In summary, our results indicated that cigarette smoking induced the activation of the RIP2/caspase-12/NF-κB axis and it played an important role in the development of OSCC. The RIP2/caspase-12/NF-κB axis could be a target for OSCC prevention and treatment in the future.

Stem cells from human exfoliated deciduous teeth attenuate trigeminal neuralgia in rats by inhibiting endoplasmic reticulum stress.

Background: The treatment of trigeminal neuralgia remains a challenging issue. Stem cells from human exfoliated deciduous teeth (SHED) provide optimized therapy for chronic pain. This study aimed to investigate the mechanisms underlying the attenuation of trigeminal neuralgia by SHED. Methods: Trigeminal neuralgia was induced by chronic constriction injury of the infraorbital nerve. The mechanical threshold was assessed after model establishment and local SHED transplantation. Endoplasmic reticulum (ER) morphology and Caspase12 expression in trigeminal ganglion (TG) was evaluated as well. BiP expression was observed in PC12 cells induced by tunicamycin. Results: The local transplantation of SHED could relieve trigeminal neuralgia in rats. Further, transmission electron microscopy revealed swelling of the ER in rats with trigeminal neuralgia. Moreover, SHED inhibited the tunicamycin-induced up-regulated expression of BiP mRNA and protein in vitro. Additionally, SHED decreased the up-regulated expression of Caspase12 mRNA and protein in the TG of rats caused by trigeminal neuralgia after chronic constriction injury of the infraorbital nerve mode. Conclusions: This findings demonstrated that SHED could alleviate pain by relieving ER stress which provide potential basic evidence for clinical pain treatment.

[Effect of acupuncture on expression of endoplasmic reticulum Ca2+ and Caspase-12 protein in hippocampal neurons of rats with convulsive brain injury].

OBJECTIVE: To observe the effect of acupuncture on endoplasmic reticulum calcium, apoptosis number and Caspase-12 protein expression in hippocampal neurons of convulsive rats, so as to explore its mechanisms underlying improvement of convulsion. METHODS: SD rats were randomly divided into normal control, model and acupuncture groups, with 36 rats in each group. Rats in the normal control group received intraperitoneal injection (i.p.) of normal saline (2 mL), and those of the other 2 groups received i.p. of pentylenetetrazole (50 mg/kg) for establishing convulsion model. Manual acupuncture stimulation was applied to "Baihui"(GV20) and "Dazhui"(GV14) for 30 min after modeling. The hippocampal tissues were taken at 2, 12 and 48 h after modeling. The endoplasmic reticulum Ca2+ concentration (optical density, OD) was detected by using fluorescence probe technique and laser confocal microscopy, and the number of apoptosis of hippocampal neurons at the 3 time points detected by using terminal-deoxynucleoitidyl transferase mediated nick end labeling (TUNEL) stain. The expression of Caspase-12 protein in hippocampus at 3 time points was observed by immunohistochemistry. RESULTS: In comparison with the normal group, the number of apoptotic cells of hippocampal neurons and the expression levels of Caspase-12 protein in hippocampus at 2, 12 and 48 h after seizures were obviously increased (P<0.01), and the OD value of Ca2+ at 3 time points significantly decreased (P<0.01) in the model group.Following acupuncture intervention, the increased levels of the number of apoptotic cells of hippocampal neurons and the expression of Caspase-12 protein in hippocampus at 3 time points and the decreased levels of OD value of Ca2+ at 3 time points were reversed in the acupuncture group (P<0.05, P<0.01). CONCLUSION: Acupuncture intervention is effective in reducing the apoptosis of hippocampal neurons in convulsion rats, which may be related to its functions in down-regulating Caspase-12 expression and promoting influx of Ca2+ in the hippocampal neurons.

Crocin attenuates inflammation of lung tissue in ovalbumin-sensitized mice by altering the expression of endoplasmic reticulum stress markers.

Endoplasmic reticulum (ER) stress plays a pivotal role in the pathogenesis of asthma. The present study aimed to investigate the reducing or suppressing effects of crocin in ovalbumin (OVA)-sensitized mice on ER stress markers. Mice were divided into six groups (n = 5 per group) including control, OVA-sensitized (OVA), OVA-treated crocin (OVA-Cr25, OVA-Cr50, and OVA-Cr100 mg/kg), and OVA-treated dexamethasone (1 mg/kg), (OVA-Dexa) groups. Animals 5 later groups were sensitized to OVA and the treatment groups received intraperitoneally crocin/dexamethasone in the last 5 days of the model. At the end of the study, lung tissue was evaluated for airway inflammation, caspase 12 and CHOP protein levels, and expression of ER stress markers using real-time-PCR. Sensitization with OVA significantly caused airway inflammation and induction of ER stress in mice compared to the control group based on the elevated inflammatory cells and ER stress markers in the lung tissue. Treatment with crocin and dexamethasone reduced airway inflammation and suppressed ER stress markers. Interestingly, in the OVA-Cr100 group, the suppressive effects on ER stress apoptotic markers were comparable to the OVA-Dexa group. The results suggest that crocin mediates maladaptive ER stress conditions possibly by creating adaptive ER stress status and driving protein folding correctly.

Proflactic effects of rosmarinic acid on spinal cord injury in rats.

PURPOSE: Spinal cord injury (SCI) causes various neurological consequences that disrupt the structure of axons. The C/EBP Homologous Protein (CHOP) acts in neuronal death by apoptosis has been demonstrated in experimental models. Rosmarinic acid (RA) is a phenolic compound used for therapeutic purposes in many diseases. In this study, we investigated the therapeutic effect of Rosmarinic acid application on inflammation and apoptotic development after spinal cord injury. METHODS: Male Wistar albino rats (n: 24) were assigned to three group: control, SCI and SCI+ RA. All rats were fixed on the operating table after anesthesia, the skin of the thoracic region was opened with a midline incision and the paravertebral muscles were dissected and T10-T11 laminas were exposed. A cylindrical tube of 10 cm length was fixed to the area to be laminectomy. A metal weight of 15 grams was left down the tube. Spinal damage was created, skin incisions were sutured. 50 mg/kg rosmarinic acid was given orally for 7 days after the spinal injury. Spinal tissues were fixed in formaldehyde solution and processed for paraffin wax tissue protocol and 4-5 µm sections were taken with microtome for further immunohistochemical examination. Caspase-12 and CHOP antibodies were applied to sections. Remaining tissues were carried out in glutaraldehyde for the first fixation then in osmium tetroxide for the second. Tissues were kept in pure araldite and thin sections were taken for transmission electron microscope. RESULTS: Values of malondialdehyde (MDA), myeloperoxidase (MPO), glutathione peroxidase (GSH), neuronal degeneration, vascular dilation, inflammation, CHOP and Caspase-12 expression were increased in SCI group compared to control group. Only glutathione peroxidase content was decreased in SCI group. In SCI group, disruption of basement membrane structure in canalis ependymalis, degeneration in structures of unipolar bipolar and multipolar neurons, and apoptotic changes were seen with increased inflammation in the piamater region and positive CHOP expression in vascular endothelial cells. In SCI+RA group, reorganization of basement membrane pill in canalis ependymalis were observed with mild Caspase-12 activity in some canalis ependymal and glial cells. Also, moderate CHOP expression in multipolar and bipolar neurons and glia cells were observed. CONCLUSIONS: The application of RA has a significant effect on preventing damage in SCI. It was thought that CHOP and Caspase-12 mediated oxidative stress could be a guide in showing the potential and therapeutic target to stop the apoptotic course after SCI injury.

Doxorubicin-induced delayed-onset subclinical cardiotoxicity in mice.

Subclinical cardiotoxicity at low total cumulative doxorubicin (DOX) doses can manifest into cardiomyopathy in long-term cancer survivors. However, the underlying mechanisms are poorly understood. In male B6C3F1 mice, assessment of cardiac function by echocardiography was performed at 1, 4, 10, 17, and 24 weeks after exposure to 6, 9, 12, and 24 mg/kg total cumulative DOX doses or saline (SAL) to monitor development of delayed-onset cardiotoxicity. The 6- or 9-mg/kg total cumulative doses resulted in a significant time-dependent decline in systolic function (left ventricular ejection fraction (LVEF) and fractional shortening (FS)) during the 24-week recovery although there was not a significant alteration in % LVEF or % FS at any specific time point during the recovery. A significant decline in systolic function was elicited by the cardiotoxic cumulative DOX dose (24 mg/kg) during the 4- to 24-week period after treatment compared to SAL-treated counterparts. At 24 weeks after DOX treatment, a significant dose-related decrease in the expression of genes and proteins involved in sarcoplasmic reticulum (SR) calcium homeostasis (Ryr2 and Serca2) was associated with a dose-related increase in the transcript level of Casp12 (SR-specific apoptosis) in hearts. These mice also showed enhanced apoptotic activity in hearts indicated by a significant dose-related elevation in the number of apoptotic cardiomyocytes compared to SAL-treated counterparts. These findings collectively suggest that a steady decline in SR calcium handling and apoptosis might be involved in the development of subclinical cardiotoxicity that can evolve into irreversible cardiomyopathy later in life.

Canagliflozin, a SGLT-2 inhibitor, relieves ER stress, modulates autophagy and induces apoptosis in irradiated HepG2 cells: Signal transduction between PI3K/AKT/GSK-3ß/mTOR and Wnt/ß-catenin pathways; in vitro.

BACKGROUND AND OBJECTIVES: Metabolic shifting from mitochondrial respiration to glycolysis characterizes malignant cells from its normal counterparts and is attributed to overactivation of oncogenic signaling pathways. Hence, this study intended to investigate the influence of canagliflozin (CAN) and/or γ-irradiation (γ-IR) on HepG2 cell proliferation, crosstalk between phosphatidylinositol 3-kinases (PI3K)/AKT/glycogen synthase kinase-3-ß (GSK3-ß)/mTOR and Wnt/ß-catenin signaling pathways, and their regulation of diverse processes, such as endoplasmic reticulum (ER) stress, autophagy, and apoptosis. MATERIALS AND METHODS: HepG2 cells were treated with different doses of CAN and then exposed to different doses of γ-IR to achieve optimization that was based on cytotoxicity and clonogenic assays, respectively. The effects of CAN and/or γ-IR on glycolytic metabolism, cellular bioenergetics, oxidative stress, ER stress and autophagy biomarkers, expression of PI3K/AKT/GSK3-ß/mTOR and Wnt/ß-Catenin signaling pathways, and apoptotic markers were monitored. RESULTS: CAN enhanced the antitumor potential of γ-IR as displayed by a significant inhibition of clonogenic survival in HepG2 cells via inhibition of glucose uptake, lactate release, and modulation of ER stress-mediated autophagy; switched it to apoptosis; as well as disabled signaling pathways which contribute to metabolic reprogramming and tumor progression induced by γ-IR that confer radioresistance and treatment failure. CONCLUSION: Our study sheds light on the effective combination of CAN and γ-IR in hepatocellular carcinoma treatment and necessitates CAN treatment prior to γ-IR to overcome metabolic reprogramming-associated radioresistance and improve curative outcomes.

Endoplasmic reticulum stress pathway mediates T-2 toxin-induced chondrocyte apoptosis.

T-2 toxin leads to chondrocyte apoptosis and excessive extracellular matrix degradation. The aim of this study is to investigate if endoplasmic reticulum stress (ERS) - initiated apoptosis is involved in the chondrocyte damage induced by T-2 toxin. In vivo, rats were divided into a control group, T-2 toxin 200 ng/g BW/d group, the protein levels of GRP78, CHOP, and caspase-12 were detected using immunohistochemistry in articular cartilage tissues. In vitro, C28/I2 and ATDC5 chondrocytes were treated with various concentrations of T-2 toxin. For the salubrinal protection assay, cells were pretreated with 20 µM salubrinal for 1 h, and treated with and without T-2 toxin for 24 h. The cell viability was determined using the MTT assay; and the cell apoptosis was determined using the Flow Cytometry Assay; the mRNA and protein levels of the ERS markers and ECM were determined using RT-PCR and western blotting. This study found that the expressions of GRP78, CHOP, and caspase-12 is higher in T-2 toxin group than in control group both in vivo and in vitro, and the T-2 toxin administration promoted chondrocyte apoptosis, suppressed matrix synthesis, and accelerated cellular catabolism via the ERS signaling pathway. In addition, this study found that salubrinal prevented chondrocyte injury by inhibiting ERS-mediated apoptosis via the PERK-eIF2α-ATF4-CHOP signaling pathway. Collectively, this study provides a new clue to elucidate the mechanism of T-2 toxin-induced chondrocyte damage, and presents a novel therapeutic possibility of salubrinal for Osteoarthropathy such as osteoarthritis (OA) and Kaschin-Beck disease (KBD).

The Role of Caspase-12 in Retinal Bystander Cell Death and Innate Immune Responses against MCMV Retinitis.

(1) Background: caspase-12 is activated during cytomegalovirus retinitis, although its role is presently unclear. (2) Methods: caspase-12-/- (KO) or caspase-12+/+ (WT) mice were immunosup eyes were analyzed by plaque assay, TUNEL assay, immunohistochemical staining, western blotting, and real-time PCR. (3) Results: increased retinitis and a more extensive virus spread were detected in the retina of infected eyes of KO mice compared to WT mice at day 14 p.i. Compared to MCMV injected WT eyes, mRNA levels of interferons α, ß and γ were significantly reduced in the neural retina of MCMV-infected KO eyes at day 14 p.i. Although similar numbers of MCMV infected cells, similar virus titers and similar numbers of TUNEL-staining cells were detected in injected eyes of both KO and WT mice at days 7 and 10 p.i., significantly lower amounts of cleaved caspase-3 and p53 protein were detected in infected eyes of KO mice at both time points. (4) Conclusions: caspase-12 contributes to caspase-3-dependent and independent retinal bystander cell death during MCMV retinitis and may also play an important role in innate immunity against virus infection of the retina.

Conditioned Medium from Mesenchymal Stem Cells Alleviates Endothelial Dysfunction of Vascular Grafts Submitted to Ischemia/Reperfusion Injury in 15-Month-Old Rats.

In patients undergoing coronary artery bypass grafting (CABG), ischemia/reperfusion injury (IRI) is the main contributor to organ dysfunction. Aging-induced vascular damage may be further aggravated during CABG. Favorable effects of conditioned medium (CM) from mesenchymal stem cells (MSCs) have been suggested against IRI. We hypothesized that adding CM to saline protects vascular grafts from IRI in rats. We found that CM contains 28 factors involved in apoptosis, inflammation, and oxidative stress. Thoracic aortic rings from 15-month-old rats were explanted and immediately mounted in organ bath chambers (aged group) or underwent 24 h of cold ischemic preservation in saline-supplemented either with vehicle (aged-IR group) or CM (aged-IR+CM group), prior to mounting. Three-month-old rats were used as referent young animals. Aging was associated with an increase in intima-to-media thickness, an increase in collagen content, higher caspase-12 mRNA levels, and immunoreactivity compared to young rats. Impaired endothelium-dependent vasorelaxation to acetylcholine in the aged-IR group compared to the aged-aorta was improved by CM (aged 61 ± 2% vs. aged-IR 38 ± 2% vs. aged-IR+CM 50 ± 3%, p < 0.05). In the aged-IR group, the already high mRNA levels of caspase-12 were decreased by CM. CM alleviates endothelial dysfunction following IRI in 15-month-old rats. The protective effect may be related to the inhibition of caspase-12 expression.

Human Caspase 12 Enhances NF-κB Activity through Activation of IKK in Nasopharyngeal Carcinoma Cells.

Human nasopharyngeal carcinoma (NPC) is a highly invasive cancer associated with proinflammation. Caspase-12 (Casp12), an inflammatory caspase, is implicated in the regulation of NF-κB-mediated cellular invasion via the modulation of the IκBα protein in NPC cells. However, the effect mechanisms of Casp12 need to be elucidated. NPC cells were transfected with the full length of human Casp12 cDNA (pC12) and the effect of human Casp12 (hCasp12) on the NF-κB activity was investigated. We found ectopic expression of hCasp12 increased the NF-κB activity accompanied by an increased p-IκBα expression and a decreased IκBα expression. Treatment of BMS, a specific IKK inhibitor, and pC12-transfected cells markedly decreased the NF-κB activity and ameliorated the expression level of IκBα reduced by hCasp12. Co-immunoprecipitation assays validated the physical interaction of hCasp12 with IKKα/ß, but not with NEMO. Furthermore, the NF-κB activity of ΔCasp12-Q (a mutated catalytic of hCasp12) transfected cells was concentration-dependently induced, but lower than that of hCasp12-transfected cells. Importantly, the hCasp12-mediated NF-kB activity was enhanced by TNFα stimulation. That indicated a role of the catalytic motif of hCasp12 in the regulation of the NF-κB activity. This study indicated hCasp12 activated the NF-κB pathway through the activation of IKK in human NPC cells.

Neuroprotective Effects of Exercise Postconditioning After Stroke via SIRT1-Mediated Suppression of Endoplasmic Reticulum (ER) Stress.

While it is well-known that pre-stroke exercise conditioning reduces the incidence of stroke and the development of comorbidities, it is unclear whether post-stroke exercise conditioning is also neuroprotective. The present study investigated whether exercise postconditioning (PostE) induced neuroprotection and elucidated the involvement of SIRT1 regulation on the ROS/ER stress pathway. Adult rats were subjected to middle cerebral artery occlusion (MCAO) followed by either: (1) resting; (2) mild exercise postconditioning (MPostE); or (3) intense exercise postconditioning (IPostE). PostE was initiated 24 h after reperfusion and performed on a treadmill. At 1 and 3 days thereafter, we determined infarct volumes, neurological defects, brain edema, apoptotic cell death through measuring pro- (BAX and Caspase-3) and anti-apoptotic (Bcl-2) proteins, and ER stress through the measurement of glucose-regulated protein 78 (GRP78), inositol-requiring 1α (IRE1α), protein kinase RNA-like endoplasmic reticulum kinase (PERK), activating transcription factor 6 (ATF6), C/EBP homologous protein (CHOP), Caspase-12, and SIRT1. Proteins were measured by Western blot. ROS production was detected by flow cytometry.Compared to resting rats, both MPostE and IPostE significantly decreased brain infarct volumes and edema, neurological deficits, ROS production, and apoptotic cell death. MPostE further increased Bcl-2 expression and Bcl-2/BAX ratio as well as BAX and Caspase-3 expressions and ROS production (*p < 0.05). Both PostE groups saw decreases in ER stress proteins, while MPostE demonstrated a further reduction in GRP78 (***p < 0.001) and Caspase-12 (*p < 0.05) expressions at 1 day and IRE1α (**p < 0.01) and CHOP (*p < 0.05) expressions at 3 days. Additionally, both PostE groups saw significant increases in SIRT1 expression.In this study, both mild and intense PostE levels induced neuroprotection after stroke through SIRT1 and ROS/ER stress pathway. Additionally, the results may provide a base for our future study regarding the regulation of SIRT1 on the ROS/ER stress pathway in the biochemical processes underlying post-stroke neuroprotection. The results suggest that mild exercise postconditioning might play a similar neuroprotective role as intensive exercise and could be an effective exercise strategy as well.

Protection against COVID-19 in African population: Immunology, genetics, and malaria clues for therapeutic targets.

BACKGROUND: There is a marked discrepancy between SARS-CoV-2 seroprevalence and COVID-19 cases and deaths in Africa. MAIN: SARS-CoV-2 stimulates humoral and cellular immunity systems, as well as mitogen-activated protein kinase (MAPK) and nuclear NF-kB signalling pathways, which regulate inflammatory gene expression and immune cell differentiation. The result is pro-inflammatory cytokines release, hyperinflammatory condition, and cytokine storm, which provoke severe lung alterations that can lead to multi-organ failure in COVID-19. Multiple genetic and immunologic factors may contribute to the severity of COVID-19 in African individuals when compared to the rest of the global population. In this article, the role of malaria, NF-kB and MAPK pathways, caspase-12 expression, high level of LAIR-1-containing antibodies, and differential glycophorins (GYPA/B) expression in COVID-19 are discussed. CONCLUSION: Understanding pathophysiological mechanisms can help identify target points for drugs and vaccines development against COVID-19. To our knowledge, this is the first study that explores this link and proposes a biological and molecular answer to the epidemiologic discrepancy in COVID-19 in Africa.

Effect of Intravenous Glutamine on Caspase-12 Expression in the Apoptosis of the Glomerular Epithelial Cells of Male Rats Exposed to Cisplatin.

OBJECTIVE: Cisplatin is potent chemotherapy for broad-spectrum malignancies treatment, but its use is limited by organ toxicity effects, including nephrotoxicity. Glutamine prevents cisplatin nephrotoxicity by inhibiting the oxidative stress in kidney cell apoptosis. METHODS: This research examined the nephroprotective effects of intravenous glutamine on the glomerular epithelium of male rats (Rattus norvegicus). 30 male rats were randomly divided into (1) P0 as the control group; (2) P1 that was administered with single dose cisplatin (20 mg/kg BW) intraperitoneal injection; and (3) P2 that was administered with intravenous injection of glutamine (100 mg/kg BW) and single-dose cisplatin (20 mg/kg BW) intraperitoneal injection. The measurement of caspase-12 expression and apoptotic cells was performed using immunohistochemical methods. RESULTS: The caspase-12 expression are as follows: P0 = 0.5 ± 0.15; P1 = 4.1 ± 0.86; P2 = 2.54 ± 0.72. The apoptotic cells are as follows: P0 = 14.5 ± 5.23 cells/field of view; P1 = 52.7 ± 17.06 cells/field of view; P2 = 31.5 ± 6.73 cells/field of view. There is a decrease in the caspase-12 expression and apoptotic cells after intravenous glutamine administration in male white rats' glomerular epithelial cells exposed to cisplatin. The decrease of caspase-12 expression is followed by a decrease in glomerular epithelium apoptosis after intravenous glutamine administration. CONCLUSION: Immunohistochemical examination can be used as a marker of the nephrotoxic effect of cisplatin on the renal glomerular epithelium. Glutamine has been observed to give nephroprotective effect to cisplatin nephrotoxic effects.
.

Tanshinone D A improves acute liver injury in mice by inhibiting Grp78/caspase-12 pathway / 中国药理学通报

Aim To investigate the protective effect of tanshinone II A on endoplasmic reticulum stress-induced acute liver injury in mice based on Grp78/ caspase-12 pathway. Methods Sixty male Kunming mice were randomly divided into normal group, model group, positive drug group and tanshinone II A low, medium and high dose groups (10, 20, 40 mg • kg"1 • d"1). Tunicamycin (1 mg • kg"1) was administered to replicate the acute liver injury model in mice. The liver pathological changes and hepatocyte apoptosis were observed 24 hours after the model was established. The serum levels of inflammatory factors and the expressions of Grp78, caspase-12, caspase-3, Bcl- 2 and Bax in liver tissues were detected. Results Compared with control group, serum AST, ALT, MDA levels increased and SOD level decreased in model group. The pathological damage and hepatocyte apoptosis were observed. The expressions of Grp78, caspase-12, caspase-3 and Bax in liver increased, the expression of Bcl-2 decreased, and the mRNA levels of Grp78 and caspase-12 were elevated. After bifendate and tanshinone II A treatment, the changes of the a- bove indicators in acute liver injury mice group were reversed. Conclusions Tanshinone IIA can improve the acute liver injury induced by tunicamycin in mice by inhibiting the activation of GRP78/caspase-12 pathway in liver tissues and reducing endoplasmic reticulum stress level.