Cathepsin S Deficiency Results in Abnormal Accumulation of Autophagosomes in Macrophages and Enhances Ang II–Induced Cardiac Inflammation

BACKGROUND: Cathepsin S (Cat S) is overexpressed in human atherosclerotic and aneurysmal tissues and may contributes to degradation of extracellular matrix, especially elastin, in inflammatory diseases. We aimed to define the role of Cat S in cardiac inflammation and fibrosis induced by angiotensin II (Ang II) in mice. METHODS AND RESULTS: Cat S-knockout (Cat S(-/-)) and littermate wild-type (WT) C57BL/6J mice were infused continuously with Ang II (750 ng/kg/min) or saline for 7 days. Cat S(-/-) mice showed severe cardiac fibrosis, including elevated expression of collagen I and α-smooth muscle actin (α-SMA), as compared with WT mice. Moreover, macrophage infiltration and expression of inflammatory cytokines (tumor necrosis factor α, transforming growth factor β and interleukin 1β) were significantly greater in Cat S(-/-) than WT hearts. These Ang II-induced effects in Cat S(-/-) mouse hearts was associated with abnormal accumulation of autophagosomes and reduced clearance of damaged mitochondria, which led to increased levels of reactive oxygen species (ROS) and activation of nuclear factor-kappa B (NF-κB) in macrophages. CONCLUSION: Cat S in lysosomes is essential for mitophagy processing in macrophages, deficiency in Cat S can increase damaged mitochondria and elevate ROS levels and NF-κB activity in hypertensive mice, so it regulates cardiac inflammation and fibrosis

Genome-wide association identifies nine common variants associated with fasting proinsulin levels and provides new insights into the pathophysiology of type 2 diabetes.

OBJECTIVE: Proinsulin is a precursor of mature insulin and C-peptide. Higher circulating proinsulin levels are associated with impaired β-cell function, raised glucose levels, insulin resistance, and type 2 diabetes (T2D). Studies of the insulin processing pathway could provide new insights about T2D pathophysiology. RESEARCH DESIGN AND METHODS: We have conducted a meta-analysis of genome-wide association tests of ∼2.5 million genotyped or imputed single nucleotide polymorphisms (SNPs) and fasting proinsulin levels in 10,701 nondiabetic adults of European ancestry, with follow-up of 23 loci in up to 16,378 individuals, using additive genetic models adjusted for age, sex, fasting insulin, and study-specific covariates. RESULTS: Nine SNPs at eight loci were associated with proinsulin levels (P < 5 × 10(-8)). Two loci (LARP6 and SGSM2) have not been previously related to metabolic traits, one (MADD) has been associated with fasting glucose, one (PCSK1) has been implicated in obesity, and four (TCF7L2, SLC30A8, VPS13C/C2CD4A/B, and ARAP1, formerly CENTD2) increase T2D risk. The proinsulin-raising allele of ARAP1 was associated with a lower fasting glucose (P = 1.7 × 10(-4)), improved β-cell function (P = 1.1 × 10(-5)), and lower risk of T2D (odds ratio 0.88; P = 7.8 × 10(-6)). Notably, PCSK1 encodes the protein prohormone convertase 1/3, the first enzyme in the insulin processing pathway. A genotype score composed of the nine proinsulin-raising alleles was not associated with coronary disease in two large case-control datasets. CONCLUSIONS: We have identified nine genetic variants associated with fasting proinsulin. Our findings illuminate the biology underlying glucose homeostasis and T2D development in humans and argue against a direct role of proinsulin in coronary artery disease pathogenesis

Retrospective evaluation of whole exome and genome mutation calls in 746 cancer samples

Funder: NCI U24CA211006Abstract: The Cancer Genome Atlas (TCGA) and International Cancer Genome Consortium (ICGC) curated consensus somatic mutation calls using whole exome sequencing (WES) and whole genome sequencing (WGS), respectively. Here, as part of the ICGC/TCGA Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium, which aggregated whole genome sequencing data from 2,658 cancers across 38 tumour types, we compare WES and WGS side-by-side from 746 TCGA samples, finding that ~80% of mutations overlap in covered exonic regions. We estimate that low variant allele fraction (VAF < 15%) and clonal heterogeneity contribute up to 68% of private WGS mutations and 71% of private WES mutations. We observe that ~30% of private WGS mutations trace to mutations identified by a single variant caller in WES consensus efforts. WGS captures both ~50% more variation in exonic regions and un-observed mutations in loci with variable GC-content. Together, our analysis highlights technological divergences between two reproducible somatic variant detection efforts

Therapeutic Suppression of miR-4261 Attenuates Colorectal Cancer by Targeting MCC

The mutated in colorectal cancer (MCC) gene is an important colorectal tumor suppressor gene, although few studies have reported the microRNA(s) that could directly target MCC in colorectal cancer. Here, we used microRNA (miRNA) target prediction algorithms, and previously reported microarray data in human colorectal cancer found that only miR-4261 was predicted by all three databases to directly target MCC. Based on specimens from our own cohort of colorectal cancer patients, we further demonstrated that miR-4261 was overexpressed in colorectal cancer. Interestingly, overexpression of miR-4261 could enhance cell proliferation and G1/S phase transition of cell cycle, and promote cell migration in HCT116 and HT29 cells, while inhibition of miR-4261 had opposite effects. Luciferase reporter assay and western blot analysis confirmed MCC as a direct target of miR-4261. MCC small interfering RNA (siRNA) could abolish the suppressive effects of miR-4261 inhibitor on cell proliferation and migration in HCT116 and HT29 cell lines. Finally, we showed that therapeutic intervention with lentivirus-based miR-4261 sponge injection could effectively reduce tumor growth and inhibit cell proliferation in colorectal cancer xenograft. Collectively, our study is the first one to unravel the functional role of miR-4261, and it provides strong evidence that inhibition of miR-4261 through targeting of MCC might exert a therapeutic effect for colorectal cancer. Keywords: colorectal cancer, miR-4261, MC

Cat S deficiency increases Ang II-induced infiltration and expression of proinflammatory cytokines in mouse heart.

<p>(<b>A</b>) Representative hematoxylin and eosin staining of WT and Cat S^−/− hearts. Bars, 50 µm. (<b>B</b>) Immunohistochemical staining and (<b>C</b>) quantification of Mac-2 positivity. Bars, 25 µm. (<b>D</b>) Immunohistochemical staining and (<b>E</b>) quantification of TNF-α and IL-1β expression. Bars, 50 µm. (<b>F</b>) Real-time PCR analysis of mRNA expression of TGF–β1, TNF-α and IL-1β in WT and Cat S KO mouse hearts. Bars, 50 µm. Data are mean±SEM (n = 4 per group). **P<0.01 <i>vs.</i> saline Cat S KO control; ^##P<0.01 <i>vs.</i> Ang II-infused WT mice.</p

Cat S deficiency enhances Ang II-induced cardiac fibrosis in mouse heart.

<p>(<b>A</b>) Representative Masson trichrome staining of WT and Cat S^−/− hearts with saline or Ang II infusion and quantitative analysis of fibrotic areas. Immunohistochemical staining and quantification of (<b>B</b>) collagen I, (<b>C</b>) transforming growth factor (TGF)- β1 (<b>D</b>) and (<b>E</b>) α-SMA in WT and Cat S^−/− hearts with saline or Ang II infusion. Bars, 50 µm. Data are mean±SEM (n = 4 per group). **P<0.01 <i>vs.</i> saline Cat S KO control; ^#P<0.05, ^##P<0.01 <i>vs.</i> Ang II-infused WT mice. ^§P<0.05 <i>vs.</i> saline WT control.</p

Angiotensin II (Ang II) increases cathepsin S (Cat S) expression in mouse heart.

<p>(<b>A</b>) Co-localization of Cat S with F4/80-positive macrophages and (<b>B</b>) α-smooth muscle actin (α-SMA) in WT and Cat S^−/− hearts. Bars, 25 µm. (<b>C)</b> Measurement of blood pressure in WT and Cat S^−/− mice. (<b>D</b>) Left ventricle ejection fraction (EF %) in WT and Cat S^−/− hearts. (<b>E</b>) Immunohistochemical staining of Ang II-induced Cat S expression in mice. Bars, 25 µm. Data are mean±SEM (n = 8 per group). **P<0.01 <i>vs</i>. saline control. ^§§P<0.01 <i>vs</i>. saline control.</p