SOCS3 dictates the transition of divergent time-phased events in granulocyte TNF-α signaling.

Tumor-necrosis factor-α (TNF-α)-driven nuclear factor-κB (NF-κB) activation and apoptosis are opposing pathways; the growing recognition of these conflicting roles of TNF-α is perplexing. Here, we show that inflammation and apoptosis are time-phased events following TNF-α signaling and that emergence of suppressor of cytokine signaling 3 (SOCS3) expression limits the ongoing NF-κB activation and promotes apoptosis; further, we suggest an altered view of how inflammatory diseases are initiated and sustained. In vitro, TNF-α (50 ng/ml) induced granulocyte SOCS3 protein, inhibited nuclear accumulation of the p65NF-κB subunit and enhanced apoptosis, as shown by DNA laddering, annexin V positivity, and overexpression of caspase-3 and Bax in the late phase, whereas the early phase was marked by NF-κB activation. Conversely, SOCS3 knockdown by small interfering RNA (siRNA) inhibited granulocyte apoptosis and enhanced nuclear accumulation of p65 and 5' lipooxygenase expression in the late phase of TNF-α signaling. As apoptosis is associated with SOCS3 abundance, we suggest that these divergent TNF-α-driven events are time-phased, interconnected, opposing control mechanisms and one of the central features through which the immune system resolves pulmonary inflammation. Dysregulation may initiate mucosal inflammation, thus changing the landscape of asthma therapy.

Protein dependent fate of hepatic cells under nicotine induced stress and curcumin ameliorated condition.

Nicotine is mainly metabolized in liver. Its abuse elicits acute phase response by activating macrophages to produce pro-inflammatory cytokines, which play critical role in apoptosis or cell proliferation. The protective pharmacological mechanism of curcumin against nicotine-induced toxicity on protein malnourished liver is still remaining unclear. This study investigated the ameliorative mechanism of curcumin against nicotine-induced toxicity and also fate of liver particularly under protein restricted condition. Female Albino-rats maintained under normal/protein-restricted diets, were subcutaneously injected with nicotine tartrate (2.5 mg/kg body weight/day) and orally supplemented with curcumin (80 mg/kg body weight/day) for 21 days. The animals were then sacrificed to dissect out liver and proceed with further experiments. Interactions of nicotine with DNA both in vivo and in vitro were observed by thermal denaturation and DNA laddering assays. Effects of nicotine on hepatic cells were monitored by differential staining, comet assay, cytokine profiling, mRNA and protein expression. Nicotine caused more intense DNA damage, promoted hepatic cell death through up-regulating pro-apoptotic proteins and signaling molecules in protein malnourished individuals. Through up-regulation of anti-apoptotic proteins and proliferation promoting molecules, nicotine dysregulated homeostasis in normal protein condition. Curcumin significantly ameliorated the nicotine-induced toxicity in both conditions and regulated the imbalance between cell survival and death induced by nicotine. The protein content present in the nicotine induced hepatic cell decides either cell-survival pathway or cytotoxic pathway.

IL-6 receptor-mediated lung Th2 cytokine networking in silica-induced pulmonary fibrosis.

Pulmonary silicosis is a deadly disease which kills thousands of people every year worldwide. The disease initially develops as an inflammatory response with recruitment of inflammatory cells into the lung controlled by multiple cytokines. The question whether these cytokines exert biological functions through signal transducing pathway remains unanswered along with the potential role of interleukin-6 receptor α (IL-6Rα) in regulating inflammatory cytokines. We aimed to assess the status of signal transducers and activator of transcription (Stat3), suppressor of cytokine signalling 3(Socs3) and inflammatory cytokines in airways of silica-exposed mice, and their relationship with IL-6Rα. Silica-exposed and silica-exposed IL-6Rα gene knockdown Balb/c mice were used in the study. Lung function was measured by plethysmography, mRNA expression of cytokines and signal molecules by qRT(2)-PCR and lung architecture by histopathology; T helper cell-type 2 (Th2) cytokines in broncho-alveolar lavage fluids were evaluated by ELISA and hydroxyproline in lung by colorimetry. Elevated levels of collagen deposition, signs of lung fibrosis, infiltration of inflammatory cells and presence of exfoliated mucosa in the lung of silica-exposed mice with concurrent increase in methacholine-induced specific resistance of airways were observed on day 60 post-exposure. In parallel, heightened expression of Th2 cytokines (IL-4, IL-5, IL-6) and signal molecules (Stat3 and Socs3) were observed in the airways of silica-exposed mice. Th1 (IL-1ß and TNF-α) cytokines are underexpressed in majority of the airways tissues of silica-exposed mice. Silencing IL-6Rα in lung of silica-exposed mice down regulated the hypermorphic mRNA pool of potential Th2 cytokines and signal molecules. Hypermorphic expression of Th2 cytokines and signal molecules in airways of silica-exposed mice are mediated through IL-6Rα.