Yuchen Jiang’s research while affiliated with Wenzhou Medical University and other places

Doublecortin-like kinase 1 (DCLK1), a microtubule-associated protein kinase, is involved in neurogenesis, and its levels are elevated in various human cancers. Recent studies suggest that DCLK1 may relate to inflammatory responses in the mouse model of colitis. However, cellular pathways engaged by DCLK1, and potential substrates of the kinase remain undefined. To understand how DCLK1 regulates inflammatory responses, we utilized the well-established lipopolysaccharide (LPS)-stimulated macrophages and mouse model. Through a range of macrophage-based and cell-free platforms, we discovered that DCLK1 binds directly with the inhibitor of κB kinase β (IKKβ) and induces IKKβ phosphorylation on Ser177/181 to initiate nuclear factor-κB (NF-κB) pathway. Deficiency in DCLK1, achieved by silencing or through pharmacological inhibition, prevented LPS-induced NF-κB activation and cytokine production in macrophages. We further show that mice with myeloid-specific DCLK1 knockout or DCLK1 inhibitor treatment are protected against LPS-induced acute lung injury and septic death. Our studies report a novel functional role of macrophage DCLK1 as a direct IKKβ regulator in inflammatory signaling and suggest targeted therapy against DCLK1 for inflammatory diseases.

Diabetic kidney disease (DKD) is considered a chronic inflammatory renal disease induced by hyperglycemia. Therefore, even meticulous control of blood glucose levels cannot prevent the progression of DKD efficiently. Management of the inflammatory response could be one of the most promising strategies for treatment. We previously validated an imidazopyridine derivative (X22) as an active compound in suppressing lipopolysaccharide-induced inflammation. However, its potential for protection against DKD has not been exanimated. In the present study, streptozotocin-induced type 1 diabetic mice were used to study the effect of X22 on DKD associated inflammation and fibrosis by Q-PCR and immunoblotting assays. The results showed that X22 significantly inhibited the production of inflammatory cytokines (IL-6, TNF-α) and fibrosis biomarkers. At the same time, kidney function was dramatically improved. To elucidate the mechanism of action of X22, we examined its effects on the NRK-52E cell line. Strikingly, X22 restored the protein level of IKB-α and blocked the nuclear translocation of P65. Collectively, the data indicate that X22 can attenuate diabetic kidney dysfunction and inflammatory injury and may represent a potential agent for the treatment of DKD. It could be a potential agent for use in the treatment of DKD.

Acute lung injury (ALI) and its severe form, acute respiratory distress syndrome (ARDS), pose a major clinical challenge. The major driving force in this syndrome is pulmonary inflammation. Recent studies have shown that the naturally occurring flavonoid kaempferol (KPF) reduces endotoxin-induced inflammatory responses in mice. However, the mechanisms of these anti-inflammatory activities are not currently known. Here, we show that enhanced inflammatory cytokine production in response to lipopolysaccharide (LPS) is due to increased TGF-β-activated kinase-1 (TAK1) phosphorylation with subsequent activation of nuclear factor-κB (NF-κB). KPF attenuates LPS-mediated production of cytokines as well as activation of NF-κB. Furthermore, we identified that KPF prevents increased K63-linked polyubiquitination on TNF receptor associated factor-6 (TRAF6) and interleukin-1 receptor-associated kinase 1 (IRAK1). K63-linked polyubiquitination is a signal leading to enhanced activation of downstream pathways including TAK1. Our study shows that KPF is effective in reducing lung damage induced by LPS by modulating TRAF6 polyubiquitination. Furthermore, our findings may provide novel molecular targets to alleviate acute lung injury.