ABSTRACT
Pericyte dysfunction, with excessive migration, hyperproliferation, and differentiation into smooth muscle-like cells contributes to vascular remodeling in Pulmonary Arterial Hypertension (PAH). Augmented expression and action of growth factors trigger these pathological changes. Endogenous factors opposing such alterations are barely known. Here, we examine whether and how the endothelial hormone C-type natriuretic peptide (CNP), signaling through the cyclic guanosine monophosphate (cGMP) -producing guanylyl cyclase B (GC-B) receptor, attenuates the pericyte dysfunction observed in PAH. The results demonstrate that CNP/GC-B/cGMP signaling is preserved in lung pericytes from patients with PAH and prevents their growth factor-induced proliferation, migration, and transdifferentiation. The anti-proliferative effect of CNP is mediated by cGMP-dependent protein kinase I and inhibition of the Phosphoinositide 3-kinase (PI3K)/AKT pathway, ultimately leading to the nuclear stabilization and activation of the Forkhead Box O 3 (FoxO3) transcription factor. Augmentation of the CNP/GC-B/cGMP/FoxO3 signaling pathway might be a target for novel therapeutics in the field of PAH.
Subject(s)
Cell Proliferation , Cyclic GMP , Forkhead Box Protein O3 , Natriuretic Peptide, C-Type , Pericytes , Signal Transduction , Humans , Pericytes/metabolism , Pericytes/pathology , Natriuretic Peptide, C-Type/metabolism , Cyclic GMP/metabolism , Forkhead Box Protein O3/metabolism , Forkhead Box Protein O3/genetics , Male , Female , Pulmonary Arterial Hypertension/metabolism , Pulmonary Arterial Hypertension/pathology , Middle Aged , Hypertension, Pulmonary/metabolism , Hypertension, Pulmonary/pathology , Adult , Receptors, Atrial Natriuretic Factor/metabolism , Receptors, Atrial Natriuretic Factor/genetics , Cells, CulturedABSTRACT
BACKGROUND/AIM: Glioma is often refractory. The accumulation of amyloid beta (Aß) in the brain is commonly associated with Alzheimer's disease (AD), but there are studies suggesting that Aß has tumor suppressor potential. The aim of this study was to identify a novel, non-invasive candidate biomarker for histological prediction and prognostic assessment of glioma. PATIENTS AND METHODS: Serum was prepared from blood samples collected preoperatively from 48 patients with WHO grade II-IV glioma between October 2004 and December 2017 at a single tertiary institution. The concentration of Aß42 was measured using the SMCxPRO immunoassay (Merck). The clinical and histological characteristics of the patients, including molecular subtypes, were reviewed. RESULTS: The mean age of the patients was 52.2±12.5 years. The mean value of serum Aß42 concentration was 7.6±7.8 pg/ml in the anaplastic astrocytoma (WHO grade III) group and 6.4±6.5 pg/ml in the glioblastoma multiforme (WHO grade IV) group. The Negative epidermal growth factor receptor (EGFR) expression was associated with higher serum Aß42 levels (p=0.020). Kaplan-Meier analysis demonstrated that patients with high serum Aß42 (>11.78 pg/ml) had significantly longer progression-free survival (PFS) (p=0.038) and overall survival (OS) (p=0.018). CONCLUSION: This study investigated serum Aß42 levels as a potential biomarker for glioma. The results showed that low serum Aß42 levels were associated with EGFR expression and poor PFS and OS. Overall, these findings suggest a potential role of Aß42 as a prognostic marker in astrocytomas.
Subject(s)
Alzheimer Disease , Glioma , Humans , Adult , Middle Aged , Amyloid beta-Peptides , Glioma/pathology , Biomarkers , ErbB Receptors/genetics , Peptide FragmentsABSTRACT
Lipids are the most energy-dense components of the diet, and their overconsumption promotes obesity and diabetes. Dietary fat content has been linked to the lipid processing activity by the intestine and its overall capacity to absorb triglycerides (TG). However, the signaling cascades driving intestinal lipid absorption in response to elevated dietary fat are largely unknown. Here, we describe an unexpected role of the protein kinase D2 (PKD2) in lipid homeostasis. We demonstrate that PKD2 activity promotes chylomicron-mediated TG transfer in enterocytes. PKD2 increases chylomicron size to enhance the TG secretion on the basolateral side of the mouse and human enterocytes, which is associated with decreased abundance of APOA4. PKD2 activation in intestine also correlates positively with circulating TG in obese human patients. Importantly, deletion, inactivation, or inhibition of PKD2 ameliorates high-fat diet-induced obesity and diabetes and improves gut microbiota profile in mice. Taken together, our findings suggest that PKD2 represents a key signaling node promoting dietary fat absorption and may serve as an attractive target for the treatment of obesity.
