Exogenous Hydrogen Sulfide Attenuates High Glucose-Induced Cardiotoxicity by Inhibiting NLRP3 Inflammasome Activation by Suppressing TLR4/NF-κB Pathway in H9c2 Cells

Background/Aims: The activation of NOD-like receptor family, pyrin domain containing3 (NLRP3) inflammasome has been shown to be positively correlated with the severity of proteinuria in chronic kidney disease (CKD) patients. Prostaglandin E2 (PGE2), an important inflammatory mediator, is also involved in various kidney injuries. The aim of the present study was to investigate the involvement of NLRP3 inflammasome and PGE2 synthetic pathway in albumin-induced renal tubular injury. Methods: Murine proximal tubular cells (mPTCs) were treated with albumin to induce cell injury. NLRP3 siRNA and specific COX-2 inhibitor NS398 were used to define their roles in mediating albumin-induced mPTC injury or the activation of COX-2/mPGES-1/PGE2 cascade. Results: In mPCTs, inhibition of NLRP3 by a small interfering RNA (siRNA) blocked albumin-induced kidney injury molecule 1 (KIM-1) upregulation, inflammatory response, and cell apoptosis. Albumin markedly activated cyclooxygenase-2 (COX-2)/ microsomal prostaglandin E synthase-1 (mPGES-1)/PGE2 pathway in this cell line, an effect largely abolished by NLRP3 silencing at both mRNA and protein levels. More interestingly, blockade of COX-2 using a specific COX-2 inhibitor NS398 markedly inhibited the upregulation of KIM-1 and inflammatory cytokines, and attenuated cell apoptosis in line with blunted PGE2 release following albumin treatment. Conclusions: The findings suggest that COX-2/mPGES-1/PGE2 axis could be activated by albumin in the proximal tubular cells via a NLRP3 inflammasome-mediated mechanism and could thus contribute to proteinuria-related renal tubular cell injury.

Section: Discussionmentioning

confidence: 99%

Activation of COX-2/mPGES-1/PGE2 Cascade via NLRP3 Inflammasome Contributes to Albumin-Induced Proximal Tubule Cell Injury

Zhuang¹,

Zhao²,

Liang³

et al. 2017

“…Inflammasome is essential for one kidney/deoxycorticosterone acetate/salt-induced hypertension in mice [24]. Hydrogen sulfide suppresses high glucose-induced cardiomyocyte inflammation by inhibiting the TLR4/NF-κB pathway and its downstream NLRP3 inflammasome activation [25]. Ang II-induced hypertension is prevented in NLRP3 gene deletion mice but not in ASC deletion mice, indicating that NLRP3 contributes to gestational hypertension independently of ASC-mediated inflammasomes [26].…”

Section: Introductionmentioning

confidence: 99%

NLRP3 Gene Deletion Attenuates Angiotensin II-Induced Phenotypic Transformation of Vascular Smooth Muscle Cells and Vascular Remodeling

Ren

Tong

et al. 2017

Background/Aims: Angiotensin (Ang) II plays vital roles in vascular inflammation and remodeling in hypertension. Phenotypic transformation of vascular smooth muscle cells (VSMCs) is a major initiating factor for vascular remodeling. The present study was designed to determine the roles of NLRP3 inflammasome activation in Ang II-induced VSMC phenotypic transformation and vascular remodeling in hypertension. Methods: Primary VSMCs from the aorta of NLRP3 knockout (NLRP3^-/-) mice and wild-type (WT) mice were treated with Ang II for 24 h. Subcutaneous infusion of Ang II via osmotic minipump for 2 weeks was used to induce vascular remodeling and hypertension in WT and NLRP3^-/- mice. Results: NLRP3 gene deletion attenuates Ang II-induced NLRP3 inflammasome activation, phenotypic transformation from a contractile phenotype to a synthetic phenotype and proliferation in primary mice VSMCs. Ang II-induced hypertension and vascular remodeling in WT mice were attenuated in NLRP3^-/- mice. Furthermore, Ang II-induced NLRP3 inflammasome activation, phenotypic transformation and proliferating cell nuclear antigen (PCNA) upregulation were inhibited in the media of aorta of NLRP3^-/- mice. Conclusions: NLRP3 inflammasome activation contributes to Ang II-induced VSMC phenotypic transformation and proliferation as well as vascular remodeling and hypertension.

“…The inflammasome is a cytoplasmic multiprotein that contains the nod-like receptor protein (Nlrp) family, adaptor protein ASC [9]. It triggers Caspase-1, IL-18 and IL-1β activation to execute inflammatory responses [9, 10]. Nlrp3 inflammasome activation has been detected in nasal mucosa of AR rats [11].…”

Section: Introductionmentioning

confidence: 99%

MicroRNA-133b Ameliorates Allergic Inflammation and Symptom in Murine Model of Allergic Rhinitis by Targeting Nlrp3

Xiao¹,

Jiang²,

Hu³

et al. 2017

Background: Emerging evidences indicate that post-transcriptional regulation by microRNAs is critical in allergic rhinitis (AR) pathogenesis. MircroRNA-133b (miR-133b) was recently suggested as a potential predictor of AR. However, the in vivo effect of miR-133b on AR is unclear. Methods: AR model was established in BALB/c mice by intraperitoneal sensitization and intranasal challenge with ovalbumin (OVA). MiR-133b agomir was then intranasally administrated to mice after OVA challenge for another 7 days. The symptom of nasal rubbing and sneezing were recorded after the last OVA challenge. Nasal mucosa tissues and serum were collected. MiR-133b expression, serum OVA-specific immunoglobulin E (IgE) concentration, proinflammatory cytokines (TNF-α, IL-4, IL-5, IL-10 and IFN-γ) levels, and Nlrp3 inflammasome activation were measured by RT-PCR, ELISA, western blotting or immunohistochemistry, respectively. Histopathologic changes were evaluated using hematoxylin and eosin and Sirius red staining. The luciferase activity and protein expression of Nlrp3 were also determined. Results: MiR-133b expression was significantly decreased in nasal mucosa of AR mice, which was restored by nasal administration with miR-133b agomir. Upregulation of miR-133b markedly reduced the concentration of OVA-specific IgE, the frequencies of nasal rubbing and sneezing, and the levels of cytokines (TNF-α, IL-4, IL-5 and IFN-γ). Levels of IL-4, IL-5, IL-10 and IFN-γ produced by cervical lymph node cells were significantly lowered in miR-133b agomir-treated mice. Moreover, miR-133b also appeared to strongly attenuate pathological alterations and eosinophils and mast cells infiltration in nasal mucosa. Notably, we demonstrated for the first time that miR-133b negatively regulated Nlrp3 expression through binding with the 3’ untranslated region of Nlrp3. Consequently, infection of miR-133b in nasal mucosa remarkably suppressed the Nlrp3 inflammasome activation, as evidenced by reduced Nlrp3, Caspase-1, ASC, IL-18 and IL-1 expressions. Conclusion: MiR-133b alleviates allergic symptom in AR mice by inhibition of Nlrp3 inflammasome-meditated inflammation. These findings provide us an insight into the potential role of miR-133b in relation to AR treatment.