Deletion of DWORF does not affect cardiac function in aging and in PLN-R14del cardiomyopathy.

The phospholamban (PLN) pathogenic gene variant p.Arg14del causes cardiomyopathy, which is characterized by perinuclear PLN protein clustering and can lead to severe heart failure (HF). Elevated expression of dwarf open reading frame (DWORF), a protein counteracting the function of PLN in the sarcoplasmic reticulum (SR), can delay disease progression in a PLN-R14del mouse model. Here, we evaluated whether deletion of DWORF (DWORF-/-) would have an opposite effect and accelerate age-dependent disease progression in wild-type (WT) mice and mice with a pathogenic PLN-R14del allele (R14Δ/+). We show that DWORF-/- mice maintained a normal left ventricular ejection fraction (LVEF) during aging and no difference with WT control mice could be observed up to 20 mo of age. R14Δ/+ mice maintained a normal cardiac function until 12 mo of age, but at 18 mo of age, LVEF was significantly reduced as compared with WT mice. Absence of DWORF did neither accelerate the R14Δ/+-induced reduction in LVEF nor enhance the increases in gene expression of markers related to cardiac remodeling and fibrosis and did not exacerbate cardiac fibrosis caused by the R14Δ/+ mutation. Together, these results demonstrate that absence of DWORF does not accelerate or exacerbate PLN-R14del cardiomyopathy in mice harboring the pathogenic R14del allele. In addition, our data indicate that DWORF appears to be dispensable for cardiac function during aging.NEW & NOTEWORTHY Although DWORF overexpression significantly delayed heart failure development and strongly prolonged life span in PLN-R14del mice, the current study shows that deletion of DWORF does not accelerate or exacerbate PLN-R14del cardiomyopathy in mice harboring the pathogenic R14del allele. In addition, DWORF appears to be dispensable for cardiac function during aging. Changes in DWORF gene expression are therefore unlikely to contribute to the clinical heterogeneity observed in patients with PLN-R14del cardiomyopathy.

Biomarker and transcriptomics profiles of serum selenium concentrations in patients with heart failure are associated with immunoregulatory processes.

BACKGROUND: Low selenium concentrations are associated with worse outcomes in heart failure (HF). However, the underlying pathophysiologic mechanisms remain incompletely understood. Therefore, we aimed to contrast serum selenium concentrations to blood biomarker and transcriptomic profiles in patients with HF. METHODS: Circulating biomarkers, whole blood transcriptomics and serum selenium measurements in a cohort of 2328 patients with HF were utilized. Penalized linear regression and gene expression analysis were used to assess biomarker and transcriptomics profiles, respectively. As a proof-of-principle, potential causal effects of selenium on excreted cytokines concentrations were investigated using human peripheral blood mononuclear cells (PBMCs). RESULTS: Mean selenium levels were 60.6 µg/L in Q1 and 122.0 µg/L in Q4. From 356 biomarkers and 20 clinical features, the penalized linear regression model yielded 44 variables with <5 % marginal false discovery rate as predictors of serum selenium. Biomarkers associated positively with selenium concentrations included: epidermal growth factor receptor (EGFR), IFN-gamma-R1, CD4, GDF15, and IL10. Biomarkers associated negatively with selenium concentrations included: PCSK9, TNFSF13, FGF21 and PAI. Additionally, 148 RNA transcripts were found differentially expressed between high and low selenium status (Padj.<0.05; log-fold-change<|0.25|). Enrichment analyses of the selected biomarkers and RNA transcripts identified similar enriched processes, including regulation processes of leukocyte differentiation and activation, as well as cytokines production. The mRNA expression of two selenoproteins (MSRB1 and GPX4) were strongly correlated with serum selenium, while GPX4, SELENOK, and SELENOS were associated with prognosis. In the in-vitro setting, PBMCs supplemented with selenium showed significantly lower abundance of several (pro-)inflammatory cytokines. CONCLUSION: These data suggest that immunoregulation is an important mechanism through which selenium might have beneficial roles in HF. The beneficial effects of higher serum selenium concentrations are likely because of global immunomodulatory effects on the abundance of cytokines. MSRB1 and GPX4 are potential modulators of and should be pursued in future research.

Divergent effects of myostatin inhibition on cardiac and skeletal muscles in a mouse model of pressure overload.

The transforming growth factor-ß (TGF-ß) superfamily member, myostatin, is a negative regulator of muscle growth and may contribute to adverse cardiac remodeling. Whether suppressing myostatin could benefit pressure-overloaded heart remains unclear. We investigated the effects of pharmacological inhibition of myostatin on cardiac fibrosis and hypertrophy in a mouse model of pressure overload induced by transverse aortic constriction (TAC). Two weeks after the surgery, TAC and sham mice were randomly divided into groups receiving mRK35, a monoclonal anti-myostatin antibody, or vehicle (PBS) for 8 wk. Significant progressive cardiac hypertrophy was observed in TAC mice, as reflected by the increased wall thickness, ventricular weight, and cross-sectional area of cardiomyocytes. In the groups treated with mRK35, compared with sham mice, cardiac fibrosis was increased in TAC mice, accompanied with elevated mRNA expression of fibrotic genes. However, among the TAC mice, mRK35 did not reduce cardiac hypertrophy or fibrosis. Body weight, lean mass, and wet weights of tibialis anterior and gastrocnemius muscle bundle were increased by mRK35. When compared with the TAC-PBS group, the TAC mice treated with mRK35 demonstrated greater forelimb grip strength and a larger mean size of gastrocnemius fibers. Our data suggest that mRK35 does not attenuate cardiac hypertrophy and fibrosis in a TAC mouse model but has positive effects on muscle mass and muscle strength. Anti-myostatin treatment may have therapeutic value against muscle wasting in cardiac vascular disease.NEW & NOTEWORTHY Recent research has highlighted the importance of inhibiting TGF-ß signaling in mitigating cardiac dysfunction and remodeling. As myostatin belongs to the TGF-ß family, we evaluated the impact of myostatin inhibition using mRK35 in TAC-operated mice. Our data demonstrate that mRK35 significantly increased body weight, muscle mass, and muscle strength but did not attenuate cardiac hypertrophy or fibrosis. Pharmacological inhibition of myostatin may provide therapeutic benefits for the management of muscle wasting in cardiovascular diseases.

Artemisinin Derivatives Stimulate DR5-Specific TRAIL-Induced Apoptosis by Regulating Wildtype P53.

Artemisinin derivatives, widely known as commercial anti-malaria drugs, may also have huge potential in treating cancer cells. It has been reported that artemisinin derivatives can overcome resistance to tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-induced apoptosis in liver and cervical cancer cells. In our study, we demonstrated that artesunate (ATS) and dihydroartemisinin (DHA) are more efficient in killing colon cancer cells compared to artemisinin (ART). ATS/DHA induces the expression of DR5 in a P53 dependent manner in HCT116 and DLD-1 cells. Both ATS and DHA overcome the resistance to DHER-induced apoptosis in HCT116, mainly through upregulating death receptor 5 (DR5). We also demonstrate that DHA sensitizes HCT116 cells to DHER-induced apoptosis via P53 regulated DR5 expression in P53 knockdown assays. Nevertheless, a lower effect was observed in DLD-1 cells, which has a single Ser241Phe mutation in the P53 DNA binding domain. Thus, the status of P53 could be one of the determinants of TRAIL resistance in some cancer cells. Finally, the combination treatment of DHA and the TRAIL variant DHER increases cell death in 3D colon cancer spheroid models, which shows its potential as a novel therapy.