Calcineurin Expression Research Articles

Lysosomal Ca2+ release-facilitated TFEB nuclear translocation alleviates ischemic brain injury by attenuating autophagic/lysosomal dysfunction in neurons

Neuronal death was frequently driven by autophagic/lysosomal dysfunction after ischemic stroke, whereas how to restore the impaired autophagic flux remained elusive. Autophagic/lysosomal signaling could be augmented after transcription factor EB (TFEB) nuclear translocation, which was facilitated by its dephosphorylation. A key TFEB dephosphorylase was calcineurin (CaN), whose activity was drastically regulated by cytosolic calcium ion concentration ([Ca2+]) controlled by lysosomal Ca2+ channel-like protein of TRPML1. Our research shows that ML-SA1, an agonist of the TRPML1 channel, significantly enhanced the lysosomal Ca2+ release and the CaN expression in penumbric neurons, subsequently promoted TFEB nuclear translocation, and greatly reversed autophagy/lysosome dysfunction. Moreover, ML-SA1 treatment significantly reduced neuronal loss, infarct size, and neurological deficits. By contrast, ML-SI3, an inhibitor of TRPML1, inhibited the lysosomal Ca2+ release conversely, aggravated the impairment of autophagic flux and consequentially exacerbated brain stroke lesion. These studies suggest that TRPML1 elevation alleviates ischemic brain injury by restoring autophagic/lysosomal dysfunction via Lysosomal Ca2+ release-facilitated TFEB nuclear translocation in neurons.

Jin-Xin-Kang alleviates heart failure by mitigating mitochondrial dysfunction through the Calcineurin/Dynamin-Related Protein 1 signaling pathway

Ethnopharmacological relevanceChronic heart failure (CHF) is a severe consequence of cardiovascular disease, marked by cardiac dysfunction. Jin-Xin-Kang (JXK) is a traditional Chinese herbal formula used for the treatment of CHF. This formula consists of seven medicinal herbs, including Ginseng (Ginseng quinquefolium (L.) Alph.Wood), Astragali Radix (Astragalus membranaceus (Fisch.) Bunge), Salvia miltiorrhiza (Salvia miltiorrhiza Bunge), Descurainiae Semen Lepidii Semen (Descurainia sophia (L.) Webb ex Prantl), Leonuri Herba (Leonurus japonicus Houtt.), Cinnamomi Ramulus (Cinnamomum cassia (L.) J.Presl), and Ilex pubescens (Ilex pubescens Hook. & Arn.). Its clinical efficacy has been validated through prospective randomized controlled studies. However, the specific mechanisms of action for this formula have yet to be elucidated. Aim of the studyThis study aimed to investigate the effect of JXK on mitochondrial function and its mechanism in the treatment of CHF. MethodsJXK components were qualitatively analyzed using UPLC-Q-Orbitrap-MS. HF was induced in mice via transverse aortic constriction (TAC). After successful model establishment, lyophilized JXK-L (4.38 g/kg) and JXK-H (13.14 g/kg) were administered for 8 weeks. In vitro, hypertrophic myocardium was induced using angiotensin II (Ang II) for 48 h, followed by JXK-L and JXK-H treatment. Network pharmacology and molecular docking techniques were used to predict the relevant targets of JXK. Cardiac function, serum markers, and histopathological changes were evaluated to assess cardiac function. Immunofluorescence of Tomm20, mitochondrial membrane potential, and ROS were measured to assess mitochondrial dysfunction. Protein expression of calcineurin (CaN) and Drp1 in the myocardium was assessed by Western blot analysis. ResultsWe detected that the active components of JXK include terpenes, glycosides, flavonoids, amino acids, and alkaloids, among others. In mice with CHF, JXK improved cardiac function and reversed ventricular remodeling. Network pharmacology indicated that JXK can inhibit the calcium signaling pathway. The molecular docking results demonstrated that the active components of JXK effectively bind with CaN. Both in vitro and in vivo experiments confirmed that JXK regulated the CaN/Drp1 pathway and alleviated mitochondrial dysfunction. ConclusionJXK can inhibit the CaN/Drp1 pathway to improve mitochondrial function, and consequently treat CHF.

Enhanced IGF-IIRα Expression Exacerbates Lipopolysaccharide-Induced Cardiac Inflammation, Hypertrophy, and Apoptosis Through Calcineurin Activation.

Cardiovascular disease is one of the leading causes of death worldwide and has a high prevalence. Insulin-like growth factor-II receptor α (IGF-IIRα) acts as a stress-inducible negative regulator. This study focused on the substantial impact of heightened expression of IGF-IIRα in cardiac myoblasts and its association with the exacerbation of cardiac dysfunction. Using lipopolysaccharide (LPS)-induced H9c2 cardiac myoblasts as a model for sepsis, we aimed to elucidate the molecular interactions between IGF-IIRα and LPS in exacerbating cardiac injury. Our findings demonstrated a synergistic induction of cardiac inflammation and hypertrophy by LPS stimulation and IGF-IIRα overexpression, leading to decreased cell survival. Excessive calcineurin activity, triggered by this combined condition, was identified as a key factor exacerbating the negative effects on cell survival. Cellular changes such as cell enlargement, disrupted actin filaments, and upregulation of hypertrophy-related and inflammation-related proteins contributed to the overall hypertrophic and inflammatory responses. Overexpression of IGF-IIRα also exacerbated apoptosis induced by LPS in H9c2 cardiac myoblasts. Inhibiting calcineurin in LPS-treated H9c2 cardiac myoblasts with IGF-IIRα overexpression effectively reversed the detrimental effects, reducing cell damage and mitigating apoptosis-related cardiac mechanisms. Our study suggests that under sepsis-like conditions in the heart with IGF-IIRα overexpression, hyperactivation of calcineurin worsens cardiac damage. Suppressing IGF-IIRα and calcineurin expression could be a potential intervention to alleviate the impact of the illness and improve cardiac function.

Myostatin promotes proliferation of bovine muscle satellite cells through activating TRPC4/Ca2+/Calcineurin/NFATc3 pathway

Myostatin (MSTN) is principally expressed in skeletal muscle and negatively regulates muscle growth and development. MSTN mutation can induce muscle overgrowth in cattle by activating cell proliferation, presenting a “double-muscle” phenotype. However, the specific regulatory mechanism is still unclear. Here, we found that Ca2+ content in muscle tissue and muscle satellite cells of MSTN mutated (MSTN-/-) cattle were significantly increased compared to wild-type (WT). Furthermore, transcriptome analysis of muscle satellite cells revealed that TRPC4 was significantly increased in MSTN-/- cattle. And the expression of TRPC4 in muscle tissue of MSTN-/- cattle was detected by RT-qPCR and Western blot, which was significantly higher than that of WT. These results suggested that MSTN mutation promoted muscle satellite cells proliferation through activation of TRPC4 channel. To further verify, ML204, a specific inhibitor of TRPC4, was used to treat MSTN-/- muscle satellite cells. We found that cell proliferation was inhibited, Calcineurin expression was downregulated, and the entry of NFATc3 into nuclei was reduced, which was similar to WT group. Thus, MSTN mutation leads to the activation of TRPC4 channel, which increases intracellular Ca2+ content, further activates Calcineurin/NFATc3 pathway, and ultimately promotes the proliferation of muscle satellite cells.

Secreted frizzled-related protein 2 ameliorates diabetic cardiomyopathy by activating mitophagy

ObjectivesSecreted frizzled-related protein 2 (SFRP2), a novel adipokine that used to be considered an inhibitor of the canonical Wnt pathway, may play a protective role in metabolic disorders. However, its effect on diabetic cardiomyopathy was still unclear. Accumulating evidence indicates that mitophagy can protect cardiac function in the diabetic heart. The present study aimed to explore the roles of SFRP2 on diabetic cardiomyopathy, focusing on the effects and mechanisms for regulating mitophagy. MethodsWild-type H9c2 cells, Sfrp2 overexpression and knockdown H9c2 cells were exposed to a glucolipotoxic milieu. Reactive oxygen species (ROS) production, cell viability, apoptosis, mitophagy and lysosomal activity were detected. The interaction of SFRP2 with frizzled 5 (FZD5), and its effect on expression and intracellular localization of transcription factor EB (TFEB) and β-catenin were also explored. Diabetic rats and Sfrp2 overexpression diabetic rats were constructed to further document the findings from the in vitro study. ResultsThe expression of SFRP2 was low and mitophagy was inhibited in H9c2 cells in a glucolipotoxic milieu. Sfrp2 overexpression activated mitophagy and reduced H9c2 cells injury, whereas Sfrp2 deficiency inhibited mitophagy and worsened this injury. Consistent with the in vitro findings, Sfrp2 overexpression ameliorated the impairment in cardiac function of diabetic rats by activating mitophagy. Sfrp2 overexpression upregulated the expression of calcineurin and TFEB, but did not affect β-catenin in vitro and in vivo. The calcineurin inhibitor tacrolimus can inhibit mitophagy and worsen cell injury in Sfrp2 overexpression H9c2 cells. Furthermore, we found that FZD5 is required for the SFRP2-induced activation of the calcineurin/TFEB pathway and interacts with SFRP2 in H9c2 cells. Transfection with small interfering RNA targeting FZD5 opposed the effects of Sfrp2 overexpression on mitophagy and cell survival in a glucolipotoxic environment. ConclusionsSFRP2 can protect the diabetic heart by interacting with FZD5 and activating the calcineurin/TFEB pathway to upregulate mitophagy in H9c2 cells.

Dietary Taurine Supplementation Improves the Meat Quality, Muscle Fiber Type, and Mitochondrial Function of Finishing Pigs.

This study investigated the effects of dietary supplementation with taurine (TAU) on the meat quality, muscle fiber type, and mitochondrial function of finishing pigs. The results demonstrated that TAU significantly increased the a* value while decreasing b*45min, L*24h, and drip loss24h and drip loss48h in the longissimus dorsi (LD) muscle. Dietary supplemented with TAU reduced the content of lactate and the glycolytic potential (GP) in the LD muscle. Dietary supplemented with TAU enhanced the oxidative fiber-related gene expression as well as increased succinic dehydrogenase and malate dehydrogenase activities while reducing lactate dehydrogenase activity. Furthermore, dietary supplementation with TAU increased the contents of mtDNA and ATP and mitochondrial function-related gene expression. Moreover, TAU enhanced the mRNA expressions of calcineurin (CaN) and nuclear factor of activated T cells c1 (NFATc1) and protein expressions of CNA and NFATc1. The results indicate that dietary TAU supplementation improves meat quality and mitochondrial biogenesis and function and promotes muscle fiber-type conversion from the glycolytic fiber to the oxidative fiber via the CaN/NFATc1 pathway.

Histone Deacetylase 6 Inhibitor CKD-WID Suppressed Monosodium Urate-Induced Osteoclast Formation by Blocking Calcineurin-NFAT Pathway in RAW 264.7 Cells

Histone deacetylase (HDAC) has been found to play a crucial role in the regulation of osteoclast differentiation and formation. This study was designed to identify the effect of the HDAC6 inhibitor CKD-WID on the receptor for the activation of nuclear factor-κB ligand (RANKL)-mediated osteoclast formation in the presence of monosodium urate (MSU) in RAW 264.7 murine macrophage cells. The expression of osteoclast-specific target genes, calcineurin, and nuclear factor of activated T-cells cytoplasmic 1 (NFATc1) was evaluated in RAW 264.7 murine macrophages treated with MSU, RANKL, or CKD-WID by real-time quantitative polymerase chain reaction and Western blot assay. The effect of CKD-WID on osteoclast formation was measured by tartrate-resistant acid phosphatase (TRAP) staining, F-actin ring formation staining, and assays for bone resorption activity. RANKL in the presence of MSU significantly induced HDAC6 gene and protein expression in RAW 264.7 cells. CKD-WID markedly suppressed the expression of osteoclast-related markers such as c-Fos, TRAP, cathepsin K, and carbonic anhydrase II induced by co-stimulation with RANKL and MSU in RAW 264.7 cells. Transcription factor NFATc1 mRNA expression and nuclear NFATc1 protein expression induced by co-stimulation with RANKL and MSU were significantly inhibited by CKD-WID treatment. CKD-WID also decreased the number of TRAP-positive multinuclear cells and F-actin ring-positive cells and attenuated bone resorption activity. Co-stimulation with RANKL and MSU increased calcineurin gene and protein expression, which was significantly blocked by CKD-WID treatment. The HDAC6 inhibitor CKD-WID suppressed MSU-induced osteoclast formation through blocking the calcineurin-NFAT pathway in RAW 264.7 cells. This suggests that HDAC6 is considered a therapeutic target in uric acid-mediated osteoclastogenesis.

Growth associated protein 43 deficiency promotes podocyte injury by activating the calmodulin/calcineurin pathway under hyperglycemia

Podocyte injury is a crucial factor in the pathogenesis of diabetic kidney disease (DKD), and finding potential therapeutic interventions that can mitigate podocyte injury holds significant clinical relevance. This study was to elucidate the role of growth associated protein-43(Gap43) in podocyte injury of high glucose (HG). We confirmed the expression of Gap43 in human glomerulus and found that Gap43 expression was downregulated in podocytes of patients with DKD and HG-treated podocytes in vitro. Gap43 knockdown in podocytes promoted podocyte apoptosis, increased migration ability and decreased nephrin expression, while overexpression of Gap43 markedly suppressed HG-induced injury. Moreover, the increased expression and activity of calcineurin (CaN) were also abrogated by overexpression Gap43 in HG. Pretreatment with a typical CaN inhibitor FK506 in Gap43 knockdown podocytes restored the injury. Mechanistically, co-immunoprecipitation experiments suggested that Gap43 could bind to calmodulin (CaM). Pull-down assay further demonstrated that Gap43 and CaM directly interacts with each other via amino acids 30–52 of Gap43 and amino acids 133–197 of CaM. In addition, we also identified Pax5 as potential transcription inhibitor factor mediating Gap43 expression. In conclusion, the study indicated that the Gap43/CaM-CaN pathway may be exploited as a promising therapeutic target for protecting against podocyte injury in high glucose.

The Possible Protective Effects of Ondansetron and Tropisetron on Optic Nerve Crush Injury in Rats.

This study aimed to evaluate the potential neuroprotective effect of cyclosporine - a calcineurin inhibitor-, ondansetron, and tropisetron-5-hydroxytryptamine (serotonin) 3 receptor (5-HT3R) antagonists-, on optic nerve crush (ONC) injury in rats. Moreover, underlying signaling activities of their beneficial neuroprotective effects were studied. Adult male rats were treated with the intravitreal administration of cyclosporine (1.6 mM), ondansetron (100 nM), and tropisetron (100 nM) immediately after the induction of ONC. Subsequently, on 7th day after surgery, the rats' retinas were extracted, and the expression of apoptotic regulators (Bax and Bcl-2) and calcineurin were studied by western blot analysis. The induction of ONC injury was associated to higher expression of Bax and calcineurin, while Bcl-2 expression was considerably decreased in these animals. Intravitreal treatment with cyclosporine (1.6 mM), ondansetron (100 nM), and tropisetron (100 nM) significantly attenuated the increased expression of Bax and calcineurin. Moreover, the treatment with these agents resulted in an elevated expression of Bcl-2 in the retina. Our findings indicate that cyclosporine, ondansetron, and tropisetron protect against ONC injury in rats, possibly via the suppression of apoptosis and modulation of calcineurin activity directly and via 5-HT3 receptors. Moreover, immunoblotting showed that tropisetron was more effective as opposed to ondansetron. Further studies are needed to evaluate the precise mechanism behind cyclosporine, ondansetron, and tropisetron activities.

Glutamate Metabolism Shapes Osteoclast Differentiation: New Potential Therapeutic Target to Block Osteoclastic Bone Resorption in Multiple Myeloma Patients

Multiple Myeloma (MM) cells are characterized by an impaired Glutamine (Gln) metabolism and Gln-addiction feature. As a result of this, MM patients have lower levels of Gln and higher levels of its main metabolite Glutamate (Glu) in the bone marrow (BM) microenvironment as compared with Smoldering MM (SMM) and Monoclonal Gammopathy of Uncertain Significance (MGUS) patients. Moreover, we have recently shown that MM-dependent Gln-exhausted microenvironment impairs osteoblast differentiation. Based on this evidence, we have hypothesized that alterations of Gln/Glu axis may have a significant impact on the activation of osteoclasts (OCLs) and in the development of osteolytic lesions. We purified BM CD14+ monocytes from a cohort of 30 patients with monoclonal gammopathies (5 MGUS, 12 SMM and 13 newly diagnosed MM (ND-MM)). Cells have been incubated in osteoclastogenic medium in the presence or absence of Glu. The samples were subsequently analyzed by real-time PCR, Western blot and TRAP staining after 3 or 14 days. Amino acid uptake and amino acid content have been assessed under the same conditions. Glu uptake inhibitors have been tested throughout osteoclastogenesis. Our data showed that the presence of Glu significantly increases the number of OCLs generated from MGUS/SMM CD14+ compared with cells differentiated in the absence of the amino acid (p<0.01). In these patients, Glu increases the expression of RANK as well as NF-κB and NFATc1 protein level pointing to a stimulatory effect on osteoclastogenic signaling pathway. On the contrary, CD14+ obtained from MM patients have a lower response to Glu probably as a consequence of the high Glu microenvironment imposed by MM cells. Consistently, MM CD14+ cells are prone to generate more OCLs also in the absence of Glu compared with CD14+ cells obtained from premalignant samples (median number of OCLs: MGUS/SMM 33, MM 123, p=0.02). The analysis of intracellular amino acids (Gln, Glu, and α-ketoglutarate (2-OG)) indicated that Glu content significantly increases after 8 days of differentiation while decreasing after 14 days pointing to a fast accumulation of Glu upon differentiation. The content of both Gln and 2-OG do not vary appreciably throughout the differentiation. These data suggest that OCLs differentiation is associated with an increased uptake of extracellular Glu. Consistently, the activity of the sodium-dependent Glu transporters EAATs, increases already after 3 days of incubation in differentiating medium without Glu, with a further increase in the presence of the amino acid. Expression analysis revealed that, among EAATs, EAAT1 (encoded by SLC1A3 gene) is responsible for the uptake of extracellular Glu upon differentiation both in the presence and in the absence of the amino acid. The expression of other Glu transporters do not change during differentiation. Selective inhibitors of EAAT1, UCPH101 and TFB-TBOA completely block the formation of multinucleated OCLs in the presence of Glu (p<0.01). In parallel to EAAT1 induction, Glu treatment increases the expression of Calcineurin, the serine/threonine phosphatase activated by increased intracellular calcium levels indicating the possible modulation of calcium signaling by Glu. In conclusion, our results indicate that high BM Glu level sustains OCLs formation by stimulating of NF-κB/NFATc1/calcineurin pathway. EAAT1 transporter is responsible for the uptake of extracellular Glu during osteoclastogenesis while its inhibition markedly blocks OCL formation. Therefore, targeting glutamate metabolism could be a therapeutic strategy to block OCL formation in MM patients.

Simvastatin attenuates the c-Raf/Erk and calcineurin-NFATc2 pathways via inhibition of Hsp90 activity during the development of heart failure

Hsp90 is a molecular chaperone that contributes to the activation and stabilization of client proteins. In our previous studies, we found that inhibition of Hsp90 delayed cardiac remodeling during the development of chronic heart failure in animal models. Simvastatin, an inhibitor of HMG-CoA reductase, has been shown to inhibit Hsp90. However, it is unclear whether simvastatin can prevent cardiac remodeling by inhibiting Hsp90. Therefore, the effects of simvastatin were examined in a rat model of chronic heart failure following myocardial infarction. The results showed that simvastatin reduced cardiac remodeling by inhibiting cardiac fibrosis. Furthermore, simvastatin decreased the expression of c-Raf and calcineurin, which are involved in intracellular signaling during the development of myocardial remodeling. In vitro, we found that the interaction of Hsp90 with c-Raf and calcineurin was reduced and the expression levels these client proteins were decreased in fibroblasts cultured in the presence of simvastatin. In addition, simvastatin also reduced proliferation, migration, and collagen production of fibroblasts. These results suggest that Hsp90 inhibition is partly responsible for the inhibitory effect of simvastatin on the development of myocardial remodeling.

The Effect of Aerobic Training before Alzheimer’s Induction on the Expression of Calcineurin and Ca2+/Calmodulin-dependent Protein Kinase II Gene in the Hippocampus of Rats with Alzheimer’s Disease

Background and Objectives Regular aerobic exercise improves learning, memory, and cognitive and Synaptic Plasticity in Alzheimer’s disease (AD) patients. The aim of this study was to evaluate the levels of calcineurin and Ca2+/calmodulin-dependent protein kinase II mRNA after four weeks of aerobic training exercises and before AD induction in the hippocampus of male Wistar rats. Subjects and Methods Thirty 8-week-old rats with an average weight of 195±20 g were initially randomly divided into two groups of aerobic exercise or rest for four weeks. Then, each group was divided into three groups of AD, sham, and injection. Then, 48 hours after the last training session, Aβ1-42, or DMSO was injected into the hippocampus. Finally, after the isolation of the hippocampus, CaN mRNA and CaMKII mRNA levels were measured. Results The results of this study showed that there was a significant difference between the groups in mRNA CaN and CaMKII mRNA levels (P&lt;0.05). The results showed that aerobic exercise and AD pre-induction had a significant effect on increasing calcineurin and Ca2+/calmodulin-dependent protein kinase II levels. Conclusion Overall, the findings of the present study showed that four weeks of aerobic training improves the molecular signaling of neuroplasticity in AD rats.

Metformin attenuates an increase of calcium-dependent and ubiquitin-proteasome markers in unloaded muscle.

Current study tested a hypothesis that during skeletal muscle unloading, calcium-dependent signaling pathways, markers of protein synthesis, and expression of E3 ubiquitin ligases can be regulated by metformin. Thirty-two male Wistar rats were randomly assigned into one of four groups: nontreated control (3C), control rats treated with metformin (3CM), 3 days of unloading/hindlimb suspension with placebo (3HS), and 3 days of unloading treated with metformin (3HSM). In soleus muscle of HS group level of phospho-AMP-activated protein kinase (p-AMPK) was decreased by 46% while ATP content was increased by 49% when compared with the control group. There was an increase of the level of phospho-CaMK II (483%) and an upregulation of Calcineurin (CaN), SERCA2a, and Calpain-1 mRNA expression (87%, 41%, and 62%, respectively, P < 0.05) in the HS group relative to the control. HS group also had increased mRNA expression of MuRF1, MAFbx, and ubiquitin (167%, 146%, and 191%, respectively, P < 0.05) when compared with the control soleus muscle. Metformin treatment impeded unloading-induced changes in soleus muscle. In conclusion, metformin treatment during 3 days of soleus muscle unloading: 1) prevented the decrease of p-AMPK and increase of ATP content; 2) affected regulation of calcium-dependent signaling pathways via level of CaMK II phosphorylation or CaMK II, CaN, SERCA2a, and Calpain-1 mRNA expression; 3) attenuated an increase in the expression of critical markers of ubiquitin-proteasome pathways MuRF1, MAFbx, and ubiquitin while not affecting the unloading-induced increase of ULK-1 marker of autophagic/lysosomal pathway.NEW & NOTEWORTHY Current study for the first time tested the hypothesis that during 3 days of soleus muscle unloading, calcium-dependent signaling pathways, markers of protein synthesis, and the expression of E3 ubiquitin ligases can be regulated by metformin. Treatment with metformin during unloading: prevented the decrease of p-AMPK and increase of ATP content, affected regulation of calcium-dependent signaling pathways, and attenuated an increase of critical markers of ubiquitin-proteasome pathways. Nevertheless, metformin treatment has not prevented soleus muscle atrophy.

Cinnarizine dissolving microneedles against microwave-induced brain injury

Microwave is commonly used in the life, manufacturing and military fields, which may induce body injuries. Brain is the major target organ of microwave radiation and microwave-induced brain injury (MIBI) can lead to insomnia, dreaminess, and a decline in learning and memory. However, there is no clinical medications are available currently. Calcium channel blockers may protect the brain tissue from microwave but most of them cannot enter the brain. Here, we selected a calcium channel blocker-cinnarizine to prepare its dissolving microneedles (MNs) for the therapy of MIBI. The cinnarizine MNs was composed of polyvinyl pyrrolidone (PVP) K90 as the tip, the photopolymerized PVP as the base and the drug, which owned high mechanical strength, leading to easily piecing the skin on the neck and high drug release in vivo. The cinnarizine MNs markedly improved the recovery of spatial memory and spontaneous exploratory behavior of the rats after microwave radiation by inhibiting the expression of calcineurin and calpain-1. The dissolving MN technique is a promising method to improve drugs into the body and perform the anti-microwave radiation action.

A-kinase anchoring protein 5-ancored calcineurin regulates the remodeling of H9c2 cardiomyocytes exposed to hypoxia and reoxygenation

ObjectiveA-kinase anchoring protein 5 (AKAP5) is involved in ventricular remodeling in rats with heart failure after myocardial infarction; however, the specific mechanism is not clear. This study investigated whether AKAP5 anchors calcineurin (CaN) to regulate the remodeling of H9c2 cardiomyocytes. MethodsH9c2 cells were subjected to hypoxia stress for 3 h and reoxygenation for 24 h to create a hypoxia-reoxygenation (H/R) model. These cells were divided into three groups: H/R (model), empty vector +H/R (NC), and siRNA-AKAP5+H/R (siRNA-AKAP5) groups. The non-H/R H9c2 cells were used as normal controls. Western blotting was used to detect cardiac hypertrophy-related protein expression in the cells, including atrial natriuretic peptide (ANP), B-type natriuretic peptide (BNP), beta myosin heavy chain (β-MHC), and phosphorylated nuclear factor of activated T-cell 3 (p-NFATc3). Phalloidin staining was used to label the cytoskeleton and the cell area in different groups was measured. Immunofluorescence staining and coimmunoprecipitation were used to study the relationship between AKAP5 and CaN. H9c2 cells pretreated with the CaN inhibitor FK506 were used to further verify the relationship between AKAP5 and CaN. ResultsIn the siRNA-AKAP5+H/R group, the expression level of cardiac hypertrophy-related proteins (ANP, BNP, and β-MHC) and CaN and the area of cardiomyocytes were significantly increased, while the p-NFATc3/NFATc3 ratio was decreased in H9c2H/R cells. AKAP5 and CaN proteins were colocalized and interacted in the cells. The CaN inhibitor significantly suppressed the expression of CaN, increased the p-NFATc3/NFATc3 ratio, and reduced the expression levels of ANP, BNP, and β-MHC proteins in the cells with low AKAP5 expression. ConclusionsAKAP5 downregulation aggravated the remodeling of cardiomyocytes after H/R. AKAP5 may anchor CaN to form a complex, which in turn activates NFATc3 dephosphorylation and expression of hypertrophy-related proteins.

Hyperhomocysteinemia Promotes Cardiac Hypertrophy in Hypertension.

Hyperhomocysteinemia (HHcy) is positively linked with several cardiovascular diseases; however, its role and underlying mechanisms in pathological cardiac hypertrophy are still unclear. Here, we focused on the effects and underlying mechanisms of HHcy in hypertensive cardiac hypertrophy, one of the most common and typical types of pathological cardiac hypertrophy. By a retrospective analysis of the association between HHcy and cardiac hypertrophy in a hypertensive cohort, we found that the prevalence of HHcy was higher in patients with hypertrophy and significantly associated with the presence of cardiac hypertrophy after adjusting for other conventional risk factors. In mice, HHcy induced by a methionine (2% wt/wt) diet feeding significantly promoted cardiac hypertrophy as well as cardiac inflammation and fibrosis induced by 3-week angiotensin ІІ (AngІІ) infusion (1000 ng/kg/min), while folic acid (0.006% wt/wt) supplement corrected HHcy and attenuated AngII-stimulated cardiac phenotypes. Mechanistic studies further showed that homocysteine (Hcy) exacerbated AngII-stimulated expression of Calcineurin and nuclear factor of activated T cells (NFAT), which could be attenuated by folic acid both in mice and in neonatal rat cardiomyocytes. Moreover, treatment with cyclosporin A, an inhibitor of Calcineurin, blocked Hcy-stimulated Calcineurin-NFAT signaling and hypertrophy in neonatal rat cardiomyocytes. In conclusion, our study indicates that HHcy promotes cardiac hypertrophy in hypertension, and Calcineurin-NFAT pathway might be involved in the pro-hypertrophic effect of Hcy.

Qingyi decoction attenuates intestinal epithelial cell injury via the calcineurin/nuclear factor of activated T-cells pathway.

BACKGROUNDRecent studies have demonstrated that dysfunction of the intestinal barrier is a significant contributing factor to the development of severe acute pancreatitis (SAP). A stable intestinal mucosa barrier functions as a major anatomic and functional barrier, owing to the balance between intestinal epithelial cell (IEC) proliferation and apoptosis. There is some evidence that calcium overload may trigger IEC apoptosis and that calcineurin (CaN)/nuclear factor of activated T-cells (NFAT) signaling might play an important role in calcium-mediated apoptosis.AIMTo investigate the potential mechanisms underlying the therapeutic effect of Qingyi decoction (QYD) in SAP.METHODSA rat model of SAP was created via retrograde infusion of sodium deoxycholate. Serum levels of amylase, tumor necrosis factor (TNF-α), interleukin (IL)-6, D-lactic acid, and diamine oxidase (DAO); histological changes; and apoptosis of IECs were examined in rats with or without QYD treatment. The expression of the two subunits of CaN and NFAT in intestinal tissue was measured via quantitative real-time polymerase chain reaction and western blotting. For in vitro studies, Caco-2 cells were treated with lipopolysaccharide (LPS) and QYD serum, and then cell viability and intracellular calcium levels were detected.RESULTSRetrograde infusion of sodium deoxycholate increased the severity of pancreatic and intestinal pathology and the levels of serum amylase, TNF-α, and IL-6. Both the indicators of intestinal mucosa damage (D-lactic acid and DAO) and the levels of IEC apoptosis were elevated in the SAP group. QYD treatment reduced the serum levels of amylase, TNF-α, IL-6, D-lactic acid, and DAO and attenuated the histological findings. IEC apoptosis associated with SAP was ameliorated under QYD treatment. In addition, the protein expression levels of the two subunits of CaN were remarkably elevated in the SAP group, and the NFATc3 gene was significantly upregulated at both the transcript and protein levels in the SAP group compared with the control group. QYD significantly restrained CaN and NFATc3 gene expression in the intestine, which was upregulated in the SAP group. Furthermore, QYD serum significantly decreased the LPS-induced elevation in intracellular free Ca2+ levels and inhibited cell death.CONCLUSIONQYD can exert protective effects against intestinal mucosa damage caused by SAP and the protective effects are mediated, at least partially, by restraining IEC apoptosis via the CaN/NFATc3 pathway.

Low androgen level impairs erectile function of rat by regulating the Ng/CaN/AKT/eNOS pathway in penile corpus cavernosum.

The mechanism by which low androgen status inhibit erectile function has not yet been clearly elucidated. Neurogranin (Ng) is a Ca2+ -sensitive calmodulin binding protein that is expressed in endothelial cells and regulates eNOS function. To investigate whether low androgen status inhibit erectile function by regulating the Ng/CaN/AKT/eNOS pathway in the penile cavernous tissue of rats. Thirty-six 8-week-old male Sprague-Dawley rats were randomly divided into six groups as follows (n=6): 4-week control group (4w-control), 4-week castration group (4w-cast), 4-week castration+testosterone replacement group (4w-cast+T), 8-week control group (8w-control), 8-week castration group (8w-cast), and 8-week castration+testosterone replacement group (8w-cast+T). Four weeks and eight weeks after surgery, the ratio of the maximum intracavernous pressure/mean arterial pressure (ICPmax/MAP) was examined. The level of NO and the expression of Ng, calcineurin (CaN), AKT, p-AKT(S473), eNOS, and p-eNOS(Ser1177) in the penile cavernous tissue of each group were determined. Ng and CaN were mainly expressed in the membrane and cytoplasm of endothelial cells and smooth muscle cells in the penile cavernous tissue of rats. The ICPmax/MAP and the concentration of NO in the cast group were significantly lower than those in the control group and cast+T replacement group (p<0.01). The expression of Ng and the ratios of p-AKT/AKT and p-eNOS/eNOS in the penile cavernous tissue of rats in the cast group were significantly lower than those in the control group and cast+T replacement group (p<0.01). The expression of CaN in the penile cavernous tissue of rats in the cast group was significantly increased compared with that in the control group and the cast+T replacement group (p<0.01). Inhibiting the expression of Ng and subsequently upregulating the expression of CaN in the rat penile cavernous tissue was one of the upstream mechanisms of low androgen status inhibiting erectile function by inhibiting the AKT/eNOS signaling pathway.

Cullin-associated and neddylation-dissociated 1 protein (CAND1) governs cardiac hypertrophy and heart failure partially through regulating calcineurin degradation

Pathological cardiac hypertrophy is a process characterized by significant disturbance of protein turnover. Cullin-associated and Neddylation-dissociated 1 (CAND1) acts as a coordinator to modulate substrate protein degradation by promoting the formation of specific cullin-based ubiquitin ligase 3 complex in response to substrate accumulation, which thereby facilitate the maintaining of normal protein homeostasis. Accumulation of calcineurin is critical in the pathogenesis of cardiac hypertrophy and heart failure. However, whether CAND1 titrates the degradation of hypertrophy related protein eg. calcineurin and regulates cardiac hypertrophy remains unknown. Therefore, we aim to explore the role of CAND1 in cardiac hypertrophy and heart failure and the underlying molecular mechanism. Here, we found that the protein level of CAND1 was increased in cardiac tissues from heart failure (HF) patients and TAC mice, whereas the mRNA level did not change. CAND1-KO+ /- aggravated TAC-induced cardiac hypertrophic phenotypes; in contrast, CAND1-Tg attenuated the maladaptive cardiac remodeling. At the molecular level, CAND1 overexpression downregulated, whereas CAND1-KO+ /- or knockdown upregulated calcineurin expression at both in vivo and in vitro conditions. Mechanistically, CAND1 overexpression favored the assembly of Cul1/atrogin1/calcineurin complex and rendered the ubiquitination and degradation of calcineurin. Notably, CAND1 deficiency-induced hypertrophic phenotypes were partially rescued by knockdown of calcineurin, and application of exogenous CAND1 prevented TAC-induced cardiac hypertrophy. Taken together, our findings demonstrate that CAND1 exerts a protective effect against cardiac hypertrophy and heart failure partially by inducing the degradation of calcineurin.

MO440: Intramyocardial Artery Fibrosis and Media Hypertrophy are Associated With Beta-Catenin and Calcineurin Expression in the Model of Arterial Hypertension and CKD

Abstract BACKGROUND AND AIMS Intramyocardial arteries (IA) are one of the components of pathological cardiac remodeling. We have previously shown that cardiomyocytes hypertrophy and interstitial fibrosis are accompanied by calcineurin (CaN) and β-catenin (βCat) up-regulation in the model of arterial hypertension (AH) and chronic kidney disease (AH-CKD). In this pilot study, we investigated whether IA remodeling is associated with CaN and βCat expressions in medial (MC) and adventitial (AC) cells in AH-CKD. METHOD AH-CKD was induced by 5/6 nephrectomy (5/6NE) in spontaneously hypertensive rats (SHR-NE, n = 8). Sham-operated (SO) SHR (SHR-SO, n = 8) and Wistar Kyoto rats (WKY-SO, n = 8) were controls. Systolic blood pressure (SBP), myocardial mass index (MMI), serum creatinine (Cr), FGF23, renal Klotho (rKl), IA wall thickness (WT), perivascular fibrosis (PF), number of AC, βCat-positive AC (βCat + AC) to all AC ratio, CaN and βCat expression in MC were analyzed for 2 months after 5/6NE or SO. RESULTS The cardiac remodeling indexes—SBP, MMI, WT, AC, PF, as well as FGF23, were higher and rKl was lower in SHRs vs WKY-SO and in SHR-NE versus SHR-SO (Table). The increase in WT was accompanied by MC hypertrophy (Figure 1) with cytoplasmic CaN expression (data not shown) and PF with the increase in the number of AC in SHR-SO vs WKY-SO (Table). PF, medial hypertrophy and fibrosis of IA were accompanied by the apparent expression of CaN and βCat in the MC (Figure 1), an increase in the total number of AC and the βCat + AC accumulation in AH-CKD (Table, Figure 2). CONCLUSION IA remodeling in the setting of AH and CKD seems to be associated with СаN and βCat up-regulation in medial and adventitial cells subpopulations. Further study is needed to identify the origin of CaN/βCat expressing cells and the mechanisms of their involvement in the pathology of vascular wall alterations.