👤 Petra Hajdu

Obesity is a global health challenge that can lead to various complications, such as metabolic syndrome, diabetes mellitus, and cardiovascular diseases. Heat shock proteins are evolutionarily conserved chaperones that help maintain cellular protein homeostasis. Their expression is dysregulated in various chronic diseases, including diabetes mellitus and hyperlipidemia, and they also regulate inflammatory processes. Therefore, the present study aimed to investigate the effects of a small heat shock protein, HSPB1, on the comorbidities and complications of obesity in a transgenic mouse model. Male and female human apolipoprotein B-100 (APOB) transgenic mice fed with a high-fat diet (HFD) from months 3-10 of age were used as a model of metabolic syndrome (MetS). To study whether HSPB1 influences the development of MetS, APOB animals were crossed with HSPB1-overexpressing mice. Age and sex-matched wild-type and human HSPB1-overexpressing mice were used as controls. Changes in cardiac morphology and function were assessed by transthoracic echocardiography at month 9. At month 10, serum triglyceride and cholesterol concentrations were determined by enzymatic colorimetric assays. Pathological changes in the liver were studied on hematoxylin-eosin-stained sections. Expression levels of genes involved in inflammation and metabolism were measured by quantitative real-time polymerase chain reaction in the liver, left ventricle, and visceral white adipose tissue (vWAT). The body weight and serum LDL-cholesterol levels were significantly higher in the APOB animals than in the wild-type mice in both sexes. Notably, HSPB1 overexpression further increased weight gain in female APOB animals. Conversely, in APOB males, HSPB1 overexpression decreased LDL-cholesterol levels without significantly affecting body weight. Furthermore, in APOB females, HSPB1 overexpression elevated Fgf-21 expression in the vWAT, restored Lpl levels, and reduced the expression of several cytokines in the liver. APOB males developed left ventricular hypertrophy (LVH) with diastolic dysfunction. HSPB1 overexpression induced LVH without cardiac dysfunction in the wild-type animals. Both sexes of APOB animals developed MetS. APOB males presented LVH with preserved ejection fraction (EF); however, APOB females showed enlarged left ventricular end-systolic volume (LVESV). In APOB animals, HSPB1 overexpression exerted a sex-dependent influence on obesity-related alterations, including weight gain, hypercholesterolemia, and hepatic and vWAT gene expression. Show less

Notch-signalling has been implicated as a pathogenetic factor and a therapeutical target in T-cell leukaemias and in some lymphomas of B-cell origin. Our aim was to investigate the role of Notch-signalling in apoptosis regulation in human non-Hodgkin B-cell lymphoma (B-NHL) cell lines and in primary chronic lymhocytic leukaemia (CLL) cells using Delta-like 4 (Dll4) ligand mediated Notch activation and gamma-secretase inhibitor (GSI) mediated Notch inhibition in vitro. The potential cross-talk of Notch with the transforming growth factor-beta (TGFb) pathway in apoptosis induction was also explored, and the effect of GSI on drug-induced apoptosis was assessed. Modulation of Notch-signalling by itself did not change the rate of apoptosis in B-NHL cell lines and in CLL cells. TGFb-induced apoptosis was decreased - but not completely abolished - by GSI in TGFb-sensitive cell lines, but resistance to the apoptotic effects of TGFb were not reversed by Notch activation or inhibition. Drug-induced apoptosis was not modified by GSI. We identified Hairy/Enhancer of Split (HES)-1 as a TGFb target gene in selected - TGFb-sensitive - B-NHL cell lines. TGFb-induced HES-1 was only partially Notch-dependent in later phases. Apoptosis regulation by TGFb and GSI was not dependent on the transcriptional regulation of c-myc. In conclusion, our data does not support a unifying role of Notch in regulating apoptosis in B-NHL, but warns that gamma-secretase inhibitors may actually counteract apoptosis in some cases. Show less