Inhibitory effect of hepatocyte growth factor on cardiomyocytes apoptosis is partly related to reduced calcium sensing receptor expression during a model of simulated ischemia/reperfusion

The RISK pathway leading to mitochondria and cardioprotection: how everything started

Ischaemic heart disease, which often manifests clinically as myocardial infarction (MI), remains a major cause of mortality worldwide. Despite the development of effective pre-clinical cardioprotective therapies, clinical translation has been disappointing. Nevertheless, the 'reperfusion injury salvage kinase' (RISK) pathway appears to be a promising target for cardioprotection. This pathway is crucial for the induction of cardioprotection by numerous pharmacological and non-pharmacological interventions, such as ischaemic conditioning. An important component of the cardioprotective effects of the RISK pathway involves the prevention of mitochondrial permeability transition pore (MPTP) opening and subsequent cardiac cell death. Here, we will review the historical perspective of the RISK pathway and focus on its interaction with mitochondria in the setting of cardioprotection.

Role of Biomaterials in Cardiac Repair and Regeneration: Therapeutic Intervention for Myocardial Infarction

Heart failure or myocardial infarction (MI) is one of the world's leading causes of death. Post MI, the heart can develop pathological conditions such as ischemia, inflammation, fibrosis, and left ventricular dysfunction. However, current surgical approaches are sufficient for enhancing myocardial perfusion but are unable to reverse the pathological changes. Tissue engineering and regenerative medicine approaches have shown promising effects in the repair and replacement of injured cardiomyocytes. Additionally, biomaterial scaffolds with or without stem cells are established to provide an effective environment for cardiac regeneration. Excipients loaded with growth factors, cytokines, oligonucleotides, and exosomes are found to help in such cardiac eventualities by promoting angiogenesis, cardiomyocyte proliferation, and reducing fibrosis, inflammation, and apoptosis. Injectable hydrogels, nanocarriers, cardiac patches, and vascular grafts are some excipients that can help the self-renewal in the damaged heart but are not understood well yet, in the context of used biomaterials. This review focuses on the use of various biomaterial-based approaches for the regeneration and repair of cardiac tissue postoccurrence of MI. It also discusses the outlines of cardiac remodeling and current therapeutic approaches after myocardial infarction, which are translationally important with respect to used biomaterials. It provides comprehensive details of the biomaterial-based regenerative approaches, which are currently the focus of the research for cardiac repair and regeneration and can provide a broad outline for further improvements.

MCP-1 mediates ischemia-reperfusion-induced cardiomyocyte apoptosis via MCPIP1 and CaSR

Monocyte chemotactic protein-1 (MCP-1) plays a crucial role in ischemia-reperfusion (I/R) injury; however, the detailed mechanism of MCP-1 in I/R injury-induced cardiomyocyte apoptosis remains unclear. In this study, we explored the cascade downstream of I/R-induced MCP-1 that modulates cell apoptosis and determined whether Ca²⁺-sensing receptors (CaSRs) are involved in the process. Protein levels were detected in a cardiac muscle cell line (HL-1) and primary cultured neonatal mouse ventricular cardiomyocytes using Western blotting and immunocytochemistry. Released MCP-1 was detected using ELISA. Both Hoechst staining and flow cytometry methods were used to measure cell apoptosis. Specific pharmacological inhibitors of CC chemokine receptor 2 (RS-102895) and CaSR (NPS-2143) as well as a CaSR activator (evocalcet) were applied to confirm the roles of these factors in I/R-induced cell apoptosis. I/R inhibited cell viability and upregulated cell apoptosis. Moreover, I/R induced the release of MCP-1 from both HL-1 cells and primary cardiomyocytes. Further research confirmed that CaSR acted as an upstream effector of monocyte chemotactic protein-1-induced protein-1 (MCPIP1) and coordinately regulated cell apoptosis, which was verified by addition of an inhibitor or activator of CaSR. Moreover, MCPIP1 induced cell apoptosis through endoplasmic reticulum (ER) stress but not autophagy induced by I/R. Based on these findings, I/R-induced MCP-1 release regulates cardiomyocyte apoptosis via the MCPIP1 and CaSR pathways, suggesting a new therapeutic strategy for I/R injury.NEW & NOTEWORTHY Ischemia-reperfusion (I/R)-induced monocyte chemotactic protein-1 release regulates cardiomyocyte apoptosis via the monocyte chemotactic protein-1-induced protein-1 (MCPIP1) and Ca²⁺-sensing receptor pathway. The functional changes mediated by MCPIP1 involve the activation of endoplasmic reticulum stress, but not the autophagy pathway, after I/R injury.

circDLPAG4/HECTD1 mediates ischaemia/reperfusion injury in endothelial cells via ER stress

Background: Vascular endothelial cell dysfunction, characterized by cell apoptosis and migration, plays a crucial role in ischaemia/reperfusion (I/R) injury, a common aspect of cardiovascular diseases. Recent studies have suggested that non-coding RNAs, such as circular RNAs (circRNA), play a role in cell dysfunction in I/R injury, although the detailed mechanism is unclear.Methods: Human umbilical vein endothelial cells (HUVECs) were used for in vitro I/R model. Protein expression was detected by western blotting (WB) and immunocytochemistry. The CRISPR/Cas9 system, WB, cell viability assays, Hoechst staining and a 3D migration model were used to explore functional changes. RNA expression was evaluated using quantitative real-time PCR and a FISH assay combined with lentivirus transfection regulating circRNAs and miRNAs. A mouse myocardial I/R model using C57 mice was established to confirm the in vitro findings.Results: In HUVECs, I/R induced a significant time-dependent decrease in HECTD1 associated with an approximately 45% decrease in cell viability and increases in cell apoptosis and migration, which were attenuated by HECTD1 overexpression. I/R-induced upregulation of endoplasmic reticulum stress was also attenuated HECTD1 overexpression. Moreover, miR-143 mimics inhibited HECTD1 expression, which was restored by circDLGAP4 overexpression, providing insight as to the molecular mechanism of I/R-induced HECTD1 in endothelial cell dysfunction.Conclusion: Our results suggest a critical role for circDLGAP4 and HECTD1 in endothelial cell dysfunction induced by I/R, providing novel insight into potential therapeutic targets for the treatment of myocardial ischaemia.

The Different Facets of Extracellular Calcium Sensors: Old and New Concepts in Calcium-Sensing Receptor Signalling and Pharmacology

The current interest of the scientific community for research in the field of calcium sensing in general and on the calcium-sensing Receptor (CaR) in particular is demonstrated by the still increasing number of papers published on this topic. The extracellular calcium-sensing receptor is the best-known G-protein-coupled receptor (GPCR) able to sense external Ca2+ changes. Widely recognized as a fundamental player in systemic Ca2+ homeostasis, the CaR is ubiquitously expressed in the human body where it activates multiple signalling pathways. In this review, old and new notions regarding the mechanisms by which extracellular Ca2+ microdomains are created and the tools available to measure them are analyzed. After a survey of the main signalling pathways triggered by the CaR, a special attention is reserved for the emerging concepts regarding CaR function in the heart, CaR trafficking and pharmacology. Finally, an overview on other Ca2+ sensors is provided.

MCPIP1-induced autophagy mediates ischemia/reperfusion injury in endothelial cells via HMGB1 and CaSR

Monocyte chemotactic protein-1-induced protein 1 (MCPIP1) plays a important role in ischemia/reperfusion (I/R) injury. Autophagy is involved in activating endothelial cells in response to I/R. However, researchers have not clearly determined whether MCPIP1 mediates I/R injury in endothelial cells via autophagy, and its downstream mechanism remains unclear. Western blotting analyses and immunocytochemistry were applied to detect protein levels were detected in HUVECs. An in vitro scratch assay was used to detect cell migration. Cells were transfected with siRNAs to knockdown MCPIP1 and high mobility group box 1 (HMGB1) expression. The pharmacological activator of autophagy rapamycin and the specific calcium-sensing receptor (CaSR) inhibitor NPS-2143 were used to confirm the roles of autophagy and CaSR in I/R injury. I/R induced HMGB1 and CaSR expression, which subsequently upreguated the migration and apoptosis of HUVECs and coincided with the increase of autophagy. HMGB1 was involved in cell migration, whereas CaSR specifically participated in I/R-induced HUVEC apoptosis. Based on these findings, I/R-induced MCPIP1 expression regulates the migration and apoptosis of HUVECs via HMGB1 and CaSR, respectively, suggesting a new therapeutic targetof I/R injury.

Stromal Cell-Derived Factor-1α Alleviates Calcium-Sensing Receptor Activation-Mediated Ischemia/Reperfusion Injury by Inhibiting Caspase-3/Caspase-9-Induced Cell Apoptosis in Rat Free Flaps

Surgical flaps are frequently affected by ischemia/reperfusion (I/R) injury. Calcium-sensing receptor (CaSR) and stromal cell-derived factor-1α (SDF-1α) are closely associated with myocardial I/R injury. This study was performed to evaluate the feasibility of applying SDF-1α to counteract CaSR activation-mediated I/R injury in ischemic free flaps. Free flaps that underwent ischemia for 3 h were equally randomized into five groups: CaCl₂, NPS2143 + CaCl₂, SDF-1α + CaCl₂, AMD3100 + SDF-1α + CaCl₂, and normal saline. The free flaps were harvested to evaluate flap necrosis and neovascularization after 2 h or 7 d of reperfusion. p-CaSR/CaSR was extensively expressed in vascular endothelial cells of free flaps after I/R injury, and activation of the SDF-1α/CXCR4 axis and NPS2143 could reduce the expression of cleaved caspase-3, caspase-9, FAS, Cyt-c, and Bax and increase Bcl-2 expression; the opposite was true after CaSR activation. Interestingly, initiation of the SDF-1α/CXCR4 axis might abrogate CaSR activation-induced I/R injury through enhancement of microvessel density. In conclusion, CaSR might become a novel therapeutic target of free flaps affected by I/R injury. Activation of the SDF-1α/CXCR4 axis and NPS2143 could counteract CaSR activation-mediated I/R injury and promote free flap survival through inhibition of caspase-3/caspase-9-related cell apoptosis and enhancement of neovascularization.

A Regenerative Cardiac Patch Formed by Spray Painting of Biomaterials onto the Heart

Layering a regenerative polymer scaffold on the surface of the heart, termed as a cardiac patch, has been proven to be effective in preserving cardiac function after myocardial infarction (MI). However, the placement of such a patch on the heart usually needs open-chest surgery, which is traumatic, therefore prevents the translation of this strategy into the clinic. We sought to device a way to apply a cardiac patch by spray painting in situ polymerizable biomaterials onto the heart with a minimally invasive procedure. To prove the concept, we used platelet fibrin gel as the "paint" material in a mouse model of MI. The use of the spraying system allowed for placement of a uniform cardiac patch on the heart in a mini-invasive manner without the need for sutures or glue. The spray treatment promoted cardiac repair and attenuated cardiac dysfunction after MI.

Multiple Endocrine Disruption by the MET/ALK Inhibitor Crizotinib in Patients With Non-small Cell Lung Cancer

OBJECTIVES

Non-small cell lung cancer (NSCLC) is a heterogenous group of disorders that can be subclassified based upon molecular characterization. Anaplastic lymphoma kinase translocation and MET aberrations occur in a subset of NSCLC. Anaplastic lymphoma kinase/MET have been shown to be inhibited by the small molecule tyrosine kinase inhibitor crizotinib. Recently, crizotinib was shown to decrease testosterone in males. Herein, we describe the effects of crizotinib on multiple hormonal axes.

MATERIALS AND METHODS

Seven consecutive patients with NSCLC who were receiving crizotinib as part of their standard care were evaluated for hormonal disruptions.

RESULTS

Primary hypogonadism was detected in 4/5 of males, whereas mildly elevated prolactin was observed in 4/7 patients. Hypocalcemia was observed in 3/7 patients. Interestingly, 5/7 patients had elevated levels of insulin-like growth factor-1 (IGF-1) levels, and the remaining 2 individuals had levels that were near the upper limits of the normal range.

CONCLUSIONS

Because of cellular cross-talk between MET and IGF-1 signaling, elevated IGF-1 levels induced by crizotinib treatment may have implications for long-term drug efficacy. Furthermore, this finding suggests a potential avenue of therapeutic synergy, namely coordinate inhibition of the MET and IGF-1 signaling pathways. Finally, as crizotinib has been recently approved, it is prudent to check hormone and calcium biomarkers and correct noted deficiencies for improved outcomes and quality of life.

Pretreatment with low-dose gadolinium chloride attenuates myocardial ischemia/reperfusion injury in rats

AIM

We have shown that low-dose gadolinium chloride (GdCl3) abolishes arachidonic acid (AA)-induced increase of cytoplasmic Ca(2+), which is known to play a crucial role in myocardial ischemia/reperfusion (I/R) injury. The present study sought to determine whether low-dose GdCl3 pretreatment protected rat myocardium against I/R injury in vitro and in vivo.

METHODS

Cultured neonatal rat ventricular myocytes (NRVMs) were treated with GdCl3 or nifedipine, followed by exposure to anoxia/reoxygenation (A/R). Cell apoptosis was detected; the levels of related signaling molecules were assessed. SD rats were intravenously injected with GdCl3 or nifedipine. Thirty min after the administration the rats were subjected to LAD coronary artery ligation followed by reperfusion. Infarction size, the release of serum myocardial injury markers and AA were measured; cell apoptosis and related molecules were assessed.

RESULTS

In A/R-treated NRVMs, pretreatment with GdCl3 (2.5, 5, 10 μmol/L) dose-dependently inhibited caspase-3 activation, death receptor-related molecules DR5/Fas/FADD/caspase-8 expression, cytochrome c release, AA release and sustained cytoplasmic Ca(2+) increases induced by exogenous AA. In I/R-treated rats, pre-administration of GdCl3 (10 mg/kg) significantly reduced the infarct size, and the serum levels of CK-MB, cardiac troponin-I, LDH and AA. Pre-administration of GdCl3 also significantly decreased the number of apoptotic cells, caspase-3 activity, death receptor-related molecules (DR5/Fas/FADD) expression and cytochrome c release in heart tissues. The positive control drug nifedipine produced comparable cardioprotective effects in vitro and in vivo.

CONCLUSION

Pretreatment with low-dose GdCl3 significantly attenuates I/R-induced myocardial apoptosis in rats by suppressing activation of both death receptor and mitochondria-mediated pathways.

Sustained functional improvement by hepatocyte growth factor-like small molecule BB3 after focal cerebral ischemia in rats and mice

Hepatocyte growth factor (HGF), efficacious in preclinical models of acute central nervous system injury, is burdened by administration of full-length proteins. A multiinstitutional consortium investigated the efficacy of BB3, a small molecule with HGF-like activity that crosses the blood-brain barrier in rodent focal ischemic stroke using Stroke Therapy Academic Industry Roundtable (STAIR) and Good Laboratory Practice guidelines. In rats, BB3, begun 6 hours after temporary middle cerebral artery occlusion (tMCAO) reperfusion, or permanent middle cerebral artery occlusion (pMCAO) onset, and continued for 14 days consistently improved long-term neurologic function independent of sex, age, or laboratory. BB3 had little effect on cerebral infarct size and no effect on blood pressure. BB3 increased HGF receptor c-Met phosphorylation and synaptophysin expression in penumbral tissue consistent with a neurorestorative mechanism from HGF-like activity. In mouse tMCAO, BB3 starting 10 minutes after reperfusion and continued for 14 days improved neurologic function that persisted for 8 weeks in some, but not all measures. Study in animals with comorbidities and those exposed to common stroke drugs are the next steps to complete preclinical assessment. These data, generated in independent, masked, and rigorously controlled settings, are the first to suggest that the HGF pathway can potentially be harnessed by BB3 for neurologic benefit after ischemic stroke.

A safety assessment of crizotinib in the treatment of ALK-positive NSCLC patients

INTRODUCTION

In the past decade, the treatment of NSCLC has been revolutionized by the discovery of key oncogenic driver mutations and the therapies that specifically target these mutations. Crizotinib has been shown to be an inhibitor of MET, anaplastic lymphoma kinase (ALK) and ROS1 receptor tyrosine kinases, and is FDA approved for ALK inhibition. Crizotinib is effective in NSCLC that harbors ALK translocations resulting in overexpression of oncogenic ALK fusion proteins.

AREAS COVERED

This paper will review crizotinib as a treatment for ALK-positive NSCLC. It will discuss the drug's adverse events, drug-drug interactions and other important clinical and safety information related to crizotinib.

EXPERT OPINION

Compared to standard chemotherapy, crizotinib shows improved progression-free survival in ALK-positive NSCLC, with patient's reporting improved quality of life. However, certain adverse events are more frequent with crizotinib versus standard chemotherapy and must be monitored for closely. The most common adverse events include ocular and gastrointestinal disturbances, cardiac and endocrine abnormalities, and peripheral edema. Many, though not all, of these side effects are likely due to the multiple tyrosine kinases inhibited by crizotinib, and will likely improve with second- and third-generation inhibitors that inhibit ALK more specifically.

Effects of recombinant adenovirus hepatocyte growth factor gene on myocardial remodeling in spontaneously hypertensive rats

BACKGROUND AND OBJECTIVES

Myocardial hypertrophy and fibrosis are important determinants of congestive heart failure. Previous work has shown that hepatocyte growth factor (HGF) can reduce acute myocardial injury and tissue fibrosis. This study was designed to examine the effects of HGF on myocardial remodeling following sustained hypertension.

METHODS AND RESULTS

There were 4 experimental groups (n = 6) that included spontaneously hypertensive rats (SHRs) injected with 0.1 mL of adenovirus (Ad)-null into the left ventricular (LV) free wall, SHR injected with 0.1 mL of Ad-HGF gene (5 × 10(9) pfu/mL), and SHR injected with 0.1 mL of normal saline, and Wistar Kyoto rats injected with 0.1 mL of Ad-null served as control. At 4 weeks after injection, rats were sacrificed, and HGF expression, myocardial fibrosis, and LV function were determined. We observed that HGF protein expression was reduced in the hearts of SHR (P < .05 vs normal control) and it was markedly increased in SHR injected with Ad-HGF (P < .01 vs SHR injected with Ad-null). Myocardial fibrosis, collagen I, LV mass index (LVMI), and LV end-diastolic pressure (LVEDP) were increased and -dP/dtmax was decreased in SHR injected with Ad-null or normal saline (P < .01 vs normal control). Upregulation of myocardial HGF expression in SHR significantly suppressed myocardial fibrosis, collagen I content, LVMI, LVEDP, and increased -dP/dtmax (all P < .05 vs SHR-Ad-null, n = 6).

CONCLUSIONS

These findings indicate that HGF expression is attenuated in hypertrophic and fibrotic myocardium of SHR. The forced increase in HGF exerts a salutary effect on myocardial fibrosis, collagen I expression, and hemodynamic parameters.

Effect of the calcium sensing receptor on rat bone marrow-derived mesenchymal stem cell proliferation through the ERK1/2 pathway

Migration and proliferation of bone marrowderived mesenchymal stem cells (BMSCs) is critical to treatment of ischemic injury. The calcium sensing receptor (CaSR) has an important role in maintaining systemic calcium homeostasis, which is related to cell proliferation, apoptosis and paracrine signaling. We hypothesize that CaSR may enhance BMSC proliferation. Rat BMSCs were incubated with various calcium concentrations for 48 h in vitro to activate CaSR. To investigate potential mechanisms responsible for growth enhancement by calcium, the rat BMSC cell cycle progression was analyzed by fluorescence-activated cell sorting (FACS), and induction of apoptosis confirmed by cytofluorimetric analysis using propidium iodide and Annexin V-FITC double staining. Since the mitogen-activated protein kinase (MAPK) signaling pathway was one of the most significantly affected by CaSR, MAPK activation was measured by western blotting. Calcium exposure significantly enhanced rat BMSCs proliferation, as well as the proportion of the population in S phase, in a dose-dependent manner, effects which were abolished by NPS2390 (a CaSR antagonist) and U0126 (a MEK1/2 inhibitor). These results demonstrate that CaSR is involved in rat BMSC proliferation, as seen by an increased proliferation index, decreased apoptosis, and ERK1/2 activation, and provide important insight into the cellular and molecular mechanisms by which CaSR affects cell proliferation. A CaSR agonist may prove useful to enhance BMSC survival during transplantation.

Calcium-sensing receptors induce apoptosis during simulated ischaemia-reperfusion in Buffalo rat liver cells

1. Calcium-sensing receptors (CaSR) exist in a variety of tissues. In 2010, we first identified its functional expression in Buffalo rat liver (BRL) cells and demonstrated that the activation of CaSR was involved in an increased intracellular calcium through the Gq subunit-phospholipase C-inositol triphosphate pathway. However, its role and related mechanism in hepatic ischaemia/reperfusion (I/R) injury is still unclear. 2. Therefore, in the present study, BRL cells were incubated in ischaemia-mimetic solution for 4 h, then reincubated in the normal culture medium for 10 h to establish a simulated I/R model. We assayed the apoptotic ratio of BRL cells by flow cytometry and Hoechst 33342 staining; analyzed the expression of CaSR, cytochrome c (Cyt-c), caspase-3, Bcl-2, Bax, extracellular signal-regulated protein kinase (ERK), and p38 by Western blotting; and measured the concentration of intracellular calcium by laser-scanning confocal microscopy. 3. The results showed that simulated I/R increased the expression of CaSR and induced apoptosis in BRL cells. GdCl(3), a specific activator of CaSR, further increased CaSR expression, intracellular calcium, and apoptosis in BRL cells during I/R. The activation of CaSR downregulated Bcl-2 expression, upregulated Cyt-c, caspase-3, and Bax expressions, and promoted p38 and ERK-1/2 phosphorylation. 4. In conclusion, increased CaSR expression plays a vital role in apoptosis induced by I/R injury, in which its mechanism is related with calcium overload and the activation of the mitochondrial and mitogen-activated protein kinase apoptotic pathways. The regulation of CaSR activity might serve as a novel pharmacological target to prevent and treat liver disease.

Intramyocardial injection of platelet gel promotes endogenous repair and augments cardiac function in rats with myocardial infarction

OBJECTIVES

This study sought to explore the therapeutic potential of platelet gel for the treatment of myocardial infarction.

BACKGROUND

Cardiac dysfunction after acute myocardial infarction is a major cause of heart failure. Current therapy relies on prompt reperfusion and blockage of secondary maladaptive pathways by small molecules. Platelet gels are biomaterials rich in cytokines and growth factors, which can be manufactured in an autologous manner and are effective in various models of wound healing. However, the potential utility of platelet gel in cardiac regeneration has yet to be tested.

METHODS

Platelet gel was derived from syngeneic rats and its morphology, biocompatibility, secretion of beneficial factors, and in vivo degradation profile were characterized.

RESULTS

After delivery into infarcted rat hearts, the gel was efficiently infiltrated by cardiomyocytes and endothelial cells. Gel-treated hearts exhibited enhanced tissue protection, greater recruitment of endogenous regeneration, higher capillary density, and less compensatory myocyte hypertrophy. The cardiac function of control-injected animals deteriorated over the 6-week time course, while that of platelet gel-injected animals did not. In addition, the gel did not exacerbate inflammation in the heart.

CONCLUSIONS

Intramyocardial injection of autologous platelet gel ameliorated cardiac dysfunction after myocardial infarction. The striking functional benefits, the simplicity of manufacturing, and the potentially autologous nature of this biomaterial provide impetus for further translation.

A novel CASR mutation in a Tunisian FHH/NSHPT family associated with a mental retardation

The calcium-sensing receptor (CASR), a plasma membrane G-protein coupled receptor, is expressed in parathyroid gland and kidney, and controls systemic calcium homeostasis. Inactivating CASR mutations have previously been identified in patients with familial hypocalciuric hypercalcemia (FHH) and neonatal severe hyperparathyroidism (NSHPT). The aim of the present study is to determine the underlying molecular defect of FHH/NSHPT disease in a consanguineous Tunisian family. Mutation screening was carried out using RFLP-PCR and direct sequencing. We found that the proband is homozygous for a novel 15 bp deletion in the exon 7 (c.1952_1966del) confirming the diagnosis of NSHPT. All the FHH members were found to be heterozygous for the novel detected mutation. The mutation, p.S651_L655del, leads to the deletion of 5 codons in the second trans-membrane domain of the CASR which is thought to be involved in the processes of ligand-induced signaling. This alteration was associated with the evidence of mental retardation in the FHH carriers and appears to be a novel inactivating mutation in the CASR gene. Our findings provide additional support for the implication of CASR gene in the FHH/NSHPT pathogenesis.