Inhibition of zymosan-induced kidney dysfunction by tyrphostin AG-490

IL-23 signaling prevents ferroptosis-driven renal immunopathology during candidiasis

During infection the host relies on pattern-recognition receptors to sense invading fungal pathogens to launch immune defense mechanisms. While fungal recognition and immune effector responses are organ and cell type specific, during disseminated candidiasis myeloid cells exacerbate collateral tissue damage. The β-glucan receptor ephrin type-A 2 receptor (EphA2) is required to initiate mucosal inflammatory responses during oral Candida infection. Here we report that EphA2 promotes renal immunopathology during disseminated candidiasis. EphA2 deficiency leads to reduced renal inflammation and injury. Comprehensive analyses reveal that EphA2 restrains IL-23 secretion from and migration of dendritic cells. IL-23 signaling prevents ferroptotic host cell death during infection to limit inflammation and immunopathology. Further, host cell ferroptosis limits antifungal effector functions via releasing the lipid peroxidation product 4-hydroxynonenal to induce various forms of cell death. Thus, we identify ferroptotic cell death as a critical pathway of Candida-mediated renal immunopathology that opens a new avenue to tackle Candida infection and inflammation.

Activation of α7 Nicotinic Acetylcholine Receptor Ameliorates Zymosan-Induced Acute Kidney Injury in BALB/c Mice

Zymosan, a natural compound, provokes acute peritonitis and multiple organ dysfunction that affects the kidney, beside other organs via exaggerated inflammatory response. The aim of the present study is to test the role of cholinergic anti-inflammatory pathway (CAP) in alleviating acute kidney injury (AKI) induced by zymosan in BALB/c mice, using galantamine, a cholinesterase inhibitor, known to act via α7 nicotinic acetylcholine receptor (α7 nAChR) to stimulate CAP. Galantamine verified its anti-inflammatory effect by elevating acetylcholine (ACh) level, while abating the interleukin-6/ janus kinase 2 (Y1007/1008)/ signal transducer and activator of transcription 3 (Y705) (IL-6/ pY(1007/1008)-JAK2/ pY705-STAT3) inflammatory axis, with a consequent inhibition in suppressor of cytokine signaling 3 (SOCS3). This effect entails also the nuclear factor-kappa B (p65)/ high mobility group box protein-1/ (NF-κB (p65)/ HMGB-1) signaling pathway. Furthermore, the reno-curattive effect of galantamine was associated by a reduction in plasma creatinine (Cr), cystatin (Cys)-C, IL-18, and renal neutrophil gelatinase-associated lipocalin (NGAL), as well as an improved histopathological structure. Blocking the α7 nAChR by methyllycaconitine abolished the beneficial effect of galantamine to document the involvement of this receptor and the CAP in the amelioration of AKI induced by zymosan.

Tyrosine kinase inhibitor tyrphostin AG490 retards chronic joint inflammation in mice

Tyrphostin AG490 is a Janus kinase (JAK) 2 inhibitor that is clinically used as an anticancer agent and is also effective in various models of inflammatory and autoimmune diseases. In this study, we examined the effects of tyrphostin AG490 on the development of collagenase-induced osteoarthritis (CIOA). Our results showed that tyrphostin-ameliorated cartilage and bone destructions. This effect was associated with decreased expression of signal transducers and activators of transcription 3 (STAT3), phosphorylated JAK2, Dickkopf homolog 1, and receptor activator of nuclear factor κB ligand (RANKL) in the joints of arthritic mice. Tyrphostin AG490 suppressed STAT3 phosphorylation and the expression of tumor necrosis factor-related apoptosis-inducing ligand and RANKL by synovial fluid cells. The drug inhibited RANKL-induced osteoclast differentiation in vitro. Molecules, such as tyrphostin AG490 that limit bone erosion and influence osteoclast generation, might have therapeutic utility in joint degenerative disorders.

Tyrosine kinase inhibitor tyrphostin AG490 reduces liver injury in LPS-induced shock

Sepsis remains a serious clinical problem despite continuous efforts to increase survival. Experimental animal models of sepsis are pointed to a great extent on blocking the activity of cytokines. A number of signal-transducing molecules are associated with the occurrence of excessive tissue inflammation. Through inhibition of tyrosine phosphorilation and thereby changing cell signaling, tyrosine kinase inhibitors can influence multiple inflammatory pathways. The purpose of the present investigation was to evaluate the effect of tyrosine kinase inhibitor tyrphostin AG490 in a mouse LPS-induced shock. Cytokine and chemokine blood levels were determined by ELISA assays. CD11b(+) Ly6C(+), CD3(+)CD69(+) and C5aR positive cell populations in the peritoneal exudate were detected by flow cytometry. The expression of iNOS and Signal Transducer and Activator of Transcription (STAT) in the liver were observed by immunohistochemistry. We found that tyrphostin AG490 inhibited Regulated upon activation normal T cell expressed and secreted (RANTES), IL-6 and IL-12 serum levels, decreased the number of CD11b(+)Ly6C(+) and CD3(+)CD69(+) subpopulations in the peritoneal exudate and prevented the decrease of cells expressing C5a receptor and TNF-alpha receptor. Tyrphostin ameliorated liver injury associated with suppressed iNOS, STAT3 and pSTAT3 expression. Our data suggest that tyrphostin AG490 diminished the degree of inflammation starting in peritoneal cavity and minimized liver dysfunction thus representing one approach for better outcome of sepsis conditions.

The role of properdin in murine zymosan-induced arthritis

Using properdin-deficient and wild-type mice, we have investigated the role of properdin in development and progression of zymosan-induced arthritis. At the initial phase of local, zymosan-induced inflammation, properdin-deficient and wild-type mice showed bone erosion, proteoglycan loss and cell infiltration. Compared to wild-type, properdin-deficient mice had reduced C5a and IL-6 but similar synovial TNF-alpha and sRANKL levels. Both groups showed a systemic immune response. Elevated IFN-gamma production and STAT1 signaling in splenocytes and a shift to Th1 response in popliteal lymph nodes were observed in properdin-deficient mice. Properdin-deficient mice had significantly less circulating zymosan-specific IgG antibodies than wild-type. In the chronic phase, the lack of properdin resulted in significant proteoglycan loss in the joints and lower cartilageneous STAT1 expression. The level of synovial C5a on day 30 was comparable in both groups, but C5aR staining was more apparent in the joints of properdin-deficient mice. Our data show that properdin is an important player in processes involved in inflammatory joint degradation.