Pharmacological inhibition of TLR4/NF‐κB with TLR4‐IN‐C34 attenuated microcystin‐leucine arginine toxicity in bovine Sertoli cells

Abstract

This study investigated the pharmacological inhibition of the toll‐like receptor 4 (TLR4) genes as a measure to attenuate microcystin‐LR (MC‐LR) reproductive toxicity. Bovine Sertoli cells were pretreated with TLR4‐IN‐C34 (C34) for 1 hour. Thereafter the pretreated and non‐pretreated Sertoli cells were cultured in medium containing 10% heat‐activated fetal bovine serum + 80 μg/L MC‐LR for 24 hours to assess the ability of TLR4‐IN‐C34 to attenuate the toxic effects of MC‐LR. The results showed that TLR4‐IN‐C34 inhibited MC‐LR‐induced mitochondria membrane damage, mitophagy and downregulation of blood‐testis barrier constituent proteins via TLR4/nuclear factor‐kappaB and mitochondria‐mediated apoptosis signaling pathway blockage. The downregulation of the mitochondria electron transport chain, energy production and DNA replication related genes (mt‐ND2, COX‐1, COX‐2, ACAT, mtTFA) and upregulation of inflammatory cytokines (interleukin [IL]‐6, tumor necrosis factor‐α, IL‐1β, interferon‐γ, IL‐4, IL‐10, IL‐13 and transforming growth factor β1) were modulated by TLR4‐IN‐C34. Taken together, we conclude that TLR4‐IN‐C34 inhibits MC‐LR‐related disruption of mitochondria membrane, mitophagy and downregulation of blood‐testis barrier proteins of the bovine Sertoli cell via cytochrome c release and TLR4 signaling blockage.

Drp1 regulates mitochondrial dysfunction and dysregulated metabolism in ischemic injury via Clec16a-, BAX-, and GSH- pathways

“…VSMCs were seeded in 20-mm-diameter confocal petri dishes at a density of 5 × 10 4 cells per well. Mitophagy in live cells was monitored using the Mitophagy detection kit (Dojindo Molecular Technologies) 28 . The level of mitophagy was defined by the area of Mtphagy dye per cell.…”

Exposure to the Harmful Algal Bloom (HAB) Toxin Microcystin-LR (MC-LR) Prolongs and Increases Severity of Dextran Sulfate Sodium (DSS)-Induced Colitis

“…NF-kB activation subsequently leads to the upregulation of pro-inflammatory cytokines, including TNF-α and IL-1β [22]. A follow up study by Adegoke et al utilized TLR4-IN-C34 (C34) to inhibit TLR4 in order to demonstrate an attenuation of MC-LR toxicity by the TLR4/NF-kB pathway [23]. Inhibition with C34 was found to attenuate damage caused by MC-LR and attenuate the production of inflammatory cytokines, including TNF-α and IL-1β [23].…”

Immunotoxic Effects Induced by Microcystins and Cylindrospermopsin: A Review

“…Moreover, changes in inflammatory parameters have been reported not only in cells from the immune system but also in hepatic cells [81,82] and bovine Sertoli cells (from testis) [71,85].…”

“…Inflammatory and immune responses are regulated by multiple signaling pathways, among which the NF-κB and mitogen-activated protein kinase (MAPK) signaling pathways, which include the extracellular signal-regulated kinase 1/2 (ERK1/2), p38, and c-Jun N-terminal kinase (JNK) pathways, are critical participants in cellular stress responses and modulate a variety of inflammatory responses [82,99,100]. Moreover, surface receptors (such as Toll-like receptors (TLRs)) have also been suggested to play a role in the observed immunomodulatory effects of MCs [71,83,85]. TLRs are known to transduce signals via adaptor proteins (e.g., MyD88), kinases (e.g., MAPKs, AKT) and transcription factors (e.g., NF-κB).…”

“…Moreover, several authors have focused on the study of transcription factors and cytokine production [37,61,62,[66][67][68][69][70]. Recently, immunological gene and protein expression, immunohistochemical analyses and immunofluorescence staining by exposure to MC-LR have been studied both in vitro [60,71] and in vivo [59,[72][73][74].…”