RESUMEN
Pulmonary hypertension (PH) is a common complication of chronic obstructive pulmonary disease (COPD) and induces increased mortality among COPD patients. However, there are no blood biomarkers to identify PH in COPD. Here, we investigated whether circulating angiogenic factors and cytokines could serve as (a) biomarker (s) for COPD-PH patients. Using Angiogenesis and Cytokine proteome profile array assay, we measured the level of 36 cytokines and 55 angiogenesis-associated proteins in plasma from four COPD patients with PH (COPD-PH) and four COPD patients without PH (COPD), respectively, tissue inhibitor of metalloproteinase 1 (TIMP-1) and thrombospondin 1(TSP-1) were significantly different between the two groups. Enzyme-linked immunosorbent assay (ELISA) was applied to measured TIMP-1 and TSP-1 in a validation cohort (COPD-PH, n = 28; COPD, n = 18), and TIMP-1 was the only factor that was significantly different between COPD-PH and COPD patients (P < 0.01). Logistic regression analysis demonstrated that elevated TIMP-1 was an independent risk factor for COPD-PH [odds ratio (OR) = 1.258, 95% CI: 1.005-1.574, P < 0.05). Next, we explored the expression level and function of TIMP-1 in human pulmonary arterial smooth muscle cells (hPASMCs) exposed to cigarette smoking extract (CSE, a major etiological factor of COPD). In cultured hPASMCs, CSE treatment increased both TIMP-1 protein level and cell proliferation, and exogenous TIMP-1 (25 ng/mL) treatment inhibited CSE-induced hPASMCs proliferation. Overall, our results indicated that TIMP-1 elevation could serve as a circulating biomarker to diagnose PH among COPD patients, and TIMP-1 elevation in COPD-PH could be adaptive.
RESUMEN
PURPOSE: Retinal ganglion cells (RGCs) apoptosis is a common characteristic of optic neuropathies. p53-induced protein with a death domain (PIDD) is a well-known regulator of genotoxic stress-induced apoptosis, which is constitutively cleaved into three main fragments: PIDD-N, PIDD-C and PIDD-CC. Thus, we aim to determine the physiological relevance of PIDD in RGCs apoptosis in an optic nerve crush (ONC) model. METHODS: All animals were evenly randomized into four groups: sham-control group, con-siRNA group, ONC group, and PIDD-siRNA group (ONC +PIDD-siRNA). Expressions of PIDD, caspase-2, Brn3a and tBid in ONC model were analyzed by Western blot and immunofluorescence. Mean densities of RGCs/mm2 were calculated with Fluoro-Gold (FG). Moreover, we tested the effect of PIDD-siRNA on ONC-induced RGCs apoptosis using TUNEL staining. RESULTS: The level of full-length PIDD was weakly present and showed no significant differences at any time points. PIDD-CC and PIDD-C were significantly up-regulated in the retina at 3 days after ONC. Meanwhile, the expression of PIDD was significantly increased in Brn3a (a marker of RGCs) positive cells, indicating that the localization of PIDD appeared to be confined to RGCs. Furthermore, inhibition of PIDD prevented RGCs apoptosis by inhibiting caspase-2 and tBid activation. CONCLUSION: Taken together, PIDD may play a crucial role in RGCs apoptosis after ONC, and this process may be relevant to caspase-2 and tBid.
