Calpain inhibition decreases oxidative stress via mitochondrial regulation in a swine model of chronic myocardial ischemia

INTRODUCTION

Calpain overexpression is implicated in mitochondrial damage leading to tissue oxidative stress and myocardial ischemic injury. The aim of this study was to determine the effects of calpain inhibition (CI) on mitochondrial impairment and oxidative stress in a swine model of chronic myocardial ischemia and metabolic syndrome.

METHODS

Yorkshire swine were fed a high-fat diet for 4 weeks to induce metabolic syndrome then underwent placement of an ameroid constrictor to the left circumflex artery. Three weeks later, animals received: no drug (control, "CON"; n= 7); a low-dose calpain inhibitor (0.12 mg/kg; "LCI", n= 7); or high-dose calpain inhibitor (0.25 mg/kg; "HCI", n=7). Treatment continued for 5 weeks, followed by tissue harvest. Cardiac tissue was assayed for protein carbonyl content, as well as antioxidant and mitochondrial protein expression. Reactive oxygen species (ROS) and mitochondrial respiration was measured in H9c2 cells following exposure to normoxia or hypoxia (1%) for 24 h with or without CI.

RESULTS

In ischemic myocardial tissue, CI was associated with decreased total oxidative stress compared to control. CI was also associated with increased expression of mitochondrial proteins superoxide dismutase 1, SDHA, and pyruvate dehydrogenase compared to control. 100 nM of calpain inhibitor decreased ROS levels and respiration in both normoxic and hypoxic H9c2 cardiomyoblasts.

CONCLUSIONS

In the setting of metabolic syndrome, CI improves oxidative stress in chronically ischemic myocardial tissue. Decreased oxidative stress may be via modulation of mitochondrial proteins involved in free radical scavenging and production.

Deep regional hyperthermia combined with modern concurrent chemoradiotherapy increases T-downstaging rate in locally advanced rectal cancer

BACKGROUND

Deep regional hyperthermia might have an additional effect on radiotherapy in treating locally advanced rectal cancer (LARC). This study aimed to investigate the role of hyperthermia combined with modern preoperative concurrent chemoradiotherapy (CRT) for LARC.

METHODS AND MATERIALS

From 2012 to 2018, 152 consecutive patients with LARC treated with neoadjuvant chemoradiation were enrolled and analyzed retrospectively. Pelvic radiotherapy (45-50 Gy) was delivered as volumetric modulated arc therapy (VMAT), concurrently with capecitabine chemotherapy. Fifty patients received hyperthermia combined with CRT (HCRT group) twice a week. Treatment response and outcomes were compared between the two groups. Furthermore, the relationships between peripheral blood neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR) and lymphocyte-to-monocyte ratio (LMR) in response to hyperthermia were analyzed.

RESULTS

Patients treated with hyperthermia had a significantly higher T-downstaging rate than those without hyperthermia (82.0 vs. 62.7%; p = .016). Hyperthermia was an independent favorable predictor of T-downstaging (odds ratio [OR] = 2.473; 95% confidence interval [CI] 1.050-5.826; p = .038). In the HCRT group, a pre-therapeutic elevated NLR (≥3) was associated with a higher T-downstaging rate (100.0 vs. 73.5%, p = .043). However, NLR was not associated with the T-downstaging rate in the CRT group. Five-year rates of locoregional recurrence-free survival (96.8 vs. 94.7%, p = .959), disease-free survival (DFS; 61.4 vs. 79.3%, p = .242), and overall survival (OS; 92.7 vs. 89.8%, p = .831) were not statistically different between the CRT and HCRT groups.

CONCLUSIONS

Hyperthermia can improve preoperative treatment response in LARC. Pretreatment NLR may be a predictive factor for hyperthermia.

Association of CAPN10 haplotype combinations with type 2 diabetes mellitus and metabolic syndrome among Egyptians: pilot study—genotyping of three CAPN10 variants

Background

T2DM is a polygenic, metabolic complex and multifactorial disease. Several genes contribute to risk of type 2 diabetes and metabolic syndrome among different populations.

Results

An relationship between three identified CAPN-10 variants [SNP-43 (rs#3792267), SNP-19 (rs#3842570) and SNP-63 (rs#5030952)] localized on 2q37 and type 2 diabetic patients with and without metabolic syndrome (MS) have been reported in our comparative study (diabetic vs health control individuals). Genotyping of study cohorts was carried out using restriction fragment length polymorphism (RFLP-PCR). Statistical analysis of data reveals that the haplotype combination 111/112 confers a significant risk for type 2 diabetes mellitus (T2DM). Patients with the homozygous haplotype combination of 122/122 are less susceptible to MS when compared to other patients carrying other haplotype combinations. Regarding obesity, a core component in MS, the haplotype combinations 111/121 and 122/122 demonstrate a significant protective role. Furthermore, the haplotype combination 111/111 displays a significant risk for high levels of total cholesterol.

Conclusion

Present findings address that these haplotype combinations 111/112, 111/121 and 122/122 of CAPN-10 SNP-43, -19 and -63 constitute unique DNA biomarker fingerprints toward susceptibility and risk for T2DM and MS among Egyptians when compared to other haplotype combinations reported in other populations of different ethnicity. To enhance the power of human evolution control nowadays, mutations and polymorphisms in target genes associated with human diseases should be well understood.

Indel detection from Whole Genome Sequencing data and association with lipid metabolism in pigs

The selection in commercial swine breeds for meat-production efficiency has been increasing among the past decades, reducing the intramuscular fat content, which has changed the sensorial and technological properties of pork. Through processes of natural adaptation and selective breeding, the accumulation of mutations has driven the genetic divergence between pig breeds. The most common and well-studied mutations are single-nucleotide polymorphisms (SNPs). However, insertions and deletions (indels) usually represents a fifth part of the detected mutations and should also be considered for animal breeding. In the present study, three different programs (Dindel, SAMtools mpileup, and GATK) were used to detect indels from Whole Genome Sequencing data of Iberian boars and Landrace sows. A total of 1,928,746 indels were found in common with the three programs. The VEP tool predicted that 1,289 indels may have a high impact on protein sequence and function. Ten indels inside genes related with lipid metabolism were genotyped in pigs from three different backcrosses with Iberian origin, obtaining different allelic frequencies on each backcross. Genome-Wide Association Studies performed in the Longissimus dorsi muscle found an association between an indel located in the C1q and TNF related 12 (C1QTNF12) gene and the amount of eicosadienoic acid (C20:2(n-6)).

Genetic identification of Ly75 as a novel quantitative trait gene for resistance to obesity in mice

Identification of causal quantitative trait genes (QTGs) governing obesity is challenging. We previously revealed that the lymphocyte antigen 75 (Ly75) gene with an immune function is a putative QTG for Pbwg1.5, a quantitative trait locus (QTL) for resistance to obesity found from wild mice (Mus musculus castaneus). The objective of this study was to identify a true QTG for Pbwg1.5 by a combined approach of a quantitative complementation test, qualitative phenotypic analyses and causal analysis using segregating populations. In a four-way cross population among an Ly75 knockout strain, a subcongenic strain carrying Pbwg1.5 and their background strains, the quantitative complementation test showed genetic evidence that the Ly75 locus is identical to Pbwg1.5. Qualitative phenotypic analyses in two intercross populations between knockout and background strains and between subcongenic and background strains suggested that Ly75 may have pleiotropic effects on weights of white fat pads and organs. Causal analysis in the intercross population between knockout and background strains revealed that only variation in fat pad weight is caused by the genotypic difference via the difference in liver Ly75 expression. The results showed that Ly75 is a true Pbwg1.5 QTG for resistance to obesity. The finding provides a novel insight for obesity biology.

Expression and effect of Calpain9 gene genetic polymorphism on slaughter indicators and intramuscular fat content in chickens

Calpain 9 (CAPN9) is expressed in the stomach and small intestine. CAPN9 has regulatory roles in hypertension, heart disease, gastric mucosal defense, and kidney disease. The involvement of CAPN9 has not been reported in the development of chickens. CAPN9 mRNA was found in adipose and muscle tissue in this study. Two linkage single nucleotide polymorphisms (SNP; G7518A and C7542G) in intron 4 were screened from 160 birds of the D2 chicken line. The 2 mutation sites were associated with carcass weight, evisceration weight, abdominal fat weight (AFW), abdominal fat percentage (AFP), and breast muscle percentage (all P < 0.05). Intramuscular fat (IMF) content was not significantly different in the 3 genotypes. But, the AA(7518)/GG(7542) genotype had the highest IMF content, highest breast muscle weight, and lower AFW and AFP. Moreover, the mRNA level of CAPN9 in abdominal fat tissue was significantly different (P < 0.05 or P < 0.01) between any 2 genotypes, consistent with AFW and AFP. In summary, the expression of CAPN9 in adipose and breast muscle tissue is reported for the first time. CAPN9 affected production performance of chickens. As a marker, the linkage G7518A and C7542G polymorphisms in intron 4 of CAPN9 could affect the production traits by regulating mRNA expression. The findings concerning the marker enrich the theoretical foundation for molecular breeding of high-quality broilers.

Molecular dynamic simulations of the catalytic subunit of calpains 1, 2, 5, and 10: Structural analysis with an aim toward drug design

Calpains are cysteine proteases involved in the development of several human chronic illnesses such as neurodegenerative diseases, cardiovascular ailments, diabetes, and obesity which constitutes them into possible therapeutic targets. Here, using molecular dynamic simulations and docking, we studied the binding of known inhibitors to representative members of classical and nonclassical calpains. Our aim is to gain better understanding on the inhibition mechanism of calpains and to develop better and more specific inhibitors. Our atomistic models confirmed the importance of calcium ions for the structure of calpains and, as a consequence, their functionality. With these models and their subsequent use in molecular docking, essential structural requirements were identified for the binding of ligands to the calpain catalytic site that provide useful information for the design of new selective calpain inhibitors.

Calpain Inhibition Attenuates Adipose Tissue Inflammation and Fibrosis in Diet-induced Obese Mice

Adipose tissue macrophages have been proposed as a link between obesity and insulin resistance. However, the mechanisms underlying these processes are not completely defined. Calpains are calcium-dependent neutral cysteine proteases that modulate cellular function and have been implicated in various inflammatory diseases. To define whether activated calpains influence diet-induced obesity and adipose tissue macrophage accumulation, mice that were either wild type (WT) or overexpressing calpastatin (CAST Tg), the endogenous inhibitor of calpains were fed with high (60% kcal) fat diet for 16 weeks. CAST overexpression did not influence high fat diet-induced body weight and fat mass gain throughout the study. Calpain inhibition showed a transient improvement in glucose tolerance at 5 weeks of HFD whereas it lost this effect on glucose and insulin tolerance at 16 weeks HFD in obese mice. However, CAST overexpression significantly reduced adipocyte apoptosis, adipose tissue collagen and macrophage accumulation as detected by TUNEL, Picro Sirius and F4/80 immunostaining, respectively. CAST overexpression significantly attenuated obesity-induced inflammatory responses in adipose tissue. Furthermore, calpain inhibition suppressed macrophage migration to adipose tissue in vitro. The present study demonstrates a pivotal role for calpains in mediating HFD-induced adipose tissue remodeling by influencing multiple functions including apoptosis, fibrosis and inflammation.

Emerging roles of calpain proteolytic systems in macrophage cholesterol handling

Calpains are Ca2+-dependent intracellular proteases that play central roles in the post-translational processing of functional proteins. In mammals, calpain proteolytic systems comprise the endogenous inhibitor calpastatin as well as 15 homologues of the catalytic subunits and two homologues of the regulatory subunits. Recent pharmacological and gene targeting studies in experimental animal models have revealed the contribution of conventional calpains, which consist of the calpain-1 and -2 isozymes, to atherosclerotic diseases. During atherogenesis, conventional calpains facilitate the CD36-dependent uptake of oxidized low-density lipoprotein (LDL), and block cholesterol efflux through ATP-binding cassette transporters in lesional macrophages, allowing the expansion of lipid-enriched atherosclerotic plaques. In addition, calpain-6, an unconventional non-proteolytic calpain, in macrophages reportedly potentiates pinocytotic uptake of native LDL, and attenuates the efferocytic clearance of apoptotic and necrotic cell corpses from the lesions. Herein, we discuss the recent progress that has been made in our understanding of how calpain contributes to atherosclerosis, in particular focusing on macrophage cholesterol handling.

De novo microduplications at 1q41, 2q37.3, and 8q24.3 in patients with VATER/VACTERL association

The acronym VATER/VACTERL association describes the combination of at least three of the following congenital anomalies: vertebral defects (V), anorectal malformations (A), cardiac defects (C), tracheoesophageal fistula with or without esophageal atresia (TE), renal malformations (R), and limb defects (L). We aimed to identify highly penetrant de novo copy number variations (CNVs) that contribute to VATER/VACTERL association. Array-based molecular karyotyping was performed in a cohort of 41 patients with VATER/VACTERL association and 6 patients with VATER/VACTERL-like phenotype including all of the patients' parents. Three de novo CNVs were identified involving chromosomal regions 1q41, 2q37.3, and 8q24.3 comprising one (SPATA17), two (CAPN10, GPR35), and three (EPPK1, PLEC, PARP10) genes, respectively. Pre-existing data from the literature prompted us to choose GPR35 and EPPK1 for mouse expression studies. Based on these studies, we prioritized GPR35 for sequencing analysis in an extended cohort of 192 patients with VATER/VACTERL association and VATER/VACTERL-like phenotype. Although no disease-causing mutation was identified, our mouse expression studies suggest GPR35 to be involved in the development of the VATER/VACTERL phenotype. Follow-up of GPR35 and the other genes comprising the identified duplications is warranted.

Expanding members and roles of the calpain superfamily and their genetically modified animals

Calpains are intracellular Ca²(+)-dependent cysteine proteases (Clan CA, family C02, EC 3.4.22.17) found in almost all eukaryotes and some bacteria. Calpains display limited proteolytic activity at neutral pH, proteolysing substrates to transform and modulate their structures and activities, and are therefore called "modulator proteases". The human genome has 15 genes that encode a calpain-like protease domain, generating diverse calpain homologues that possess combinations of several functional domains such as Ca²(+)-binding domains and Zn-finger domains. The importance of the physiological roles of calpains is reflected in the fact that particular defects in calpain functionality cause a variety of deficiencies in many different organisms, including lethality, muscular dystrophies, lissencephaly, and tumorigenesis. In this review, the unique characteristics of this distinctive protease superfamily are introduced in terms of genetically modified animals, some of which are animal models of calpain deficiency diseases.

Mapping the epistatic network underlying murine reproductive fatpad variation

Genome-wide mapping analyses are now commonplace in many species and several networks of interacting loci have been reported. However, relatively few details regarding epistatic interactions and their contribution to complex trait variation in multicellular organisms are available and the identification of positional candidate loci for epistatic QTL (epiQTL) is hampered, especially in mammals, by the limited genetic resolution inherent in most study designs. Here we further investigate the genetic architecture of reproductive fatpad weight in mice using the F(10) generation of the LG,SM advanced intercross (AI) line. We apply multiple mapping techniques including a single-locus model, locus-specific composite interval mapping (CIM), and tests for multiple QTL per chromosome to the 12 chromosomes known to harbor single-locus QTL (slQTL) affecting obesity in this cross. We also perform a genome-wide scan for pairwise epistasis. Using this combination of approaches we detect 199 peaks spread over all 19 autosomes, which potentially contribute to trait variation including all eight original F(2) loci (Adip1-8), novel slQTL peaks on chromosomes 7 and 9, and several novel epistatic loci. Extensive epistasis is confirmed involving both slQTL confidence intervals (C.I.) as well as regions that show no significant additive or dominance effects. These results provide important new insights into mapping complex genetic architectures and the role of epistasis in complex trait variation.

Genetic, epigenetic, and gene-by-diet interaction effects underlie variation in serum lipids in a LG/JxSM/J murine model

Variation in serum cholesterol, free-fatty acids, and triglycerides is associated with cardiovascular disease (CVD) risk factors. There is great interest in characterizing the underlying genetic architecture of these risk factors, because they vary greatly within and among human populations and between the sexes. We present results of a genome-wide scan for quantitative trait loci (QTL) affecting serum cholesterol, free-fatty acids, and triglycerides in an F(16) advanced intercross line of LG/J and SM/J (Wustl:LG,SM-G16). Half of the population was fed a high-fat diet and half was fed a relatively low-fat diet. Context-dependent genetic (additive and dominance) and epigenetic (imprinting) effects were characterized by partitioning animals into sex, diet, and sex-by-diet cohorts. Here we examine genetic, environmental, and genetic-by-environmental interactions of QTL overlapping previously identified loci associated with CVD risk factors, and we add to the serum lipid QTL landscape by identifying new loci.