ABSTRACT
Accumulating evidence has implicated impaired extracellular matrix (ECM) clearance as a key factor in fibrotic disease. Despite decades of research elucidating the effectors of ECM clearance, relatively little is understood regarding the upstream regulation of this process. Collagen is the most abundant constituent of normal and fibrotic ECM in mammalian tissues. Its catabolism occurs through extracellular proteolysis and cell-mediated uptake of collagen fragments for intracellular degradation. Given the paucity of information regarding the regulation of this latter process, we executed unbiased genome-wide screens to understand the molecular underpinnings of cell-mediated collagen clearance. Using this approach, we discovered a previously unappreciated mechanism through which collagen biosynthesis is sensed by cells internally and directly regulates clearance of extracellular collagen. The sensing mechanism is dependent on endoplasmic reticulum-resident protein SEL1L and occurs via a noncanonical function of SEL1L. This pathway functions as a homeostatic negative feedback loop that limits collagen accumulation in tissues. In human fibrotic lung disease, the induction of this collagen clearance pathway by collagen synthesis is impaired, thereby contributing to the pathological accumulation of collagen in lung tissue. Thus cell-autonomous, rheostatic collagen clearance is a previously unidentified pathway of tissue homeostasis.
ABSTRACT
ETHNOPHARMACOLOGICAL RELEVANCE: Cousinia thomsonii is traditionally known for treating various diseases including joint pain, swelling, body ache, asthma, dermatitis, cough and arthritis. AIM OF THE STUDY: This study employs lipopolysaccharide induced inflammatory wistar-rat model to evaluate efficacy of Cousinia thomsonii active-extracts on the expression of crucial inflammatory markers viz. iNOS, PPAR-γ, Rel-A, COX-2 and serum analysis of CRP. MATERIALS AND METHODS: Methanol and aqueous extracts were administered orally at 25, 50, 100 mg/kg doses for 21 days. Serum was collected on 22nd day and rats were sacrificed to extract paw tissues. Dexamethasone (0.5 mg/kg) served as positive control. Immunoblotting and qPCR was used for expression analysis of iNOS, PPAR-γ, Rel-A, COX-2 respectively. ELISA was employed for evaluating CRP levels. Discovery-studio and Auto-Dock-Vina were used to check docking interactions of various identified compounds. RESULTS: Both extracts caused dose-dependent decline in iNOS, Rel-A, COX-2 and CRP levels, while there was a dose-dependent increase in PPAR-γ expression. Methanol extract dominated immunomodulatory potential as compared with the aqueous extract. The results of the GCMS revealed the presence of ten compounds. Some of these compounds include 1-Octacosanol, Ethyl Linoleate, 1-Heptacosanol, 1-Hexadecanol, 1-Dodecanol and Behenic alcohol having strong anti-inflammatory, antimicrobial, anti-acne and anti-viral activities. Molecular Docking scores were calculated between each target protein and selected compounds. The best affinity/interactions were observed between 1-Octacosanol towards iNOS, PPAR-γ, Rel-A, COX-2 and CRP with binding energy of -10.4, -11.1, -8.6, -9.9 and -7.9 (kcal/mol) respectively. These compounds may act as strong inhibitors for iNOS, Rel-A, COX-2 and CRP or as agonists for PPAR-γ; thereby inducing anti-inflammatory/immuno-modulatory activities. CONCLUSIONS: The results indicate that Cousinia thomsonii contains therapeutically active compounds and thus could serve as potential therapeutic regimen against diverse inflammatory diseases.
