Reorienting of pramipexole as a promising therapy for acute pancreatitis in a rat model by suppressing TLR-4\NF-κB p65\NLRP3 inflammasome signaling

Therapeutic Significance of NLRP3 Inflammasome in Cancer: Friend or Foe?

Besides various infectious and inflammatory complications, recent studies also indicated the significance of NLRP3 inflammasome in cancer progression and therapy. NLRP3-mediated immune response and pyroptosis could be helpful or harmful in the progression of cancer, and also depend on the nature of the tumor microenvironment. The activation of NLRP3 inflammasome could increase immune surveillance and the efficacy of immunotherapy. It can also lead to the removal of tumor cells by the recruitment of phagocytic macrophages, T-lymphocytes, and other immune cells to the tumor site. On the other hand, NLRP3 activation can also be harmful, as chronic inflammation driven by NLRP3 supports tumor progression by creating an environment that facilitates cancer cell proliferation, migration, invasion, and metastasis. The release of pro-inflammatory cytokines such as IL-1β and IL-18 can promote tumor growth and angiogenesis, while sustained inflammation may lead to immune suppression, hindering effective anti-tumor responses. In this review article, we discuss the role of NLRP3 inflammasome-mediated inflammatory response in the pathophysiology of various cancer types; understanding this role is essential for the development of innovative therapeutic strategies for cancer growth and spread.

miR-605-3p may affect caerulein-induced ductal cell injury and pyroptosis in acute pancreatitis by targeting the DUOX2/NLRP3/NF-κB pathway

Acute pancreatitis (AP) is a sudden-onset disease of the digestive system caused by abnormal activation of pancreatic enzymes. Dual oxidase 2 (DUOX2) has been found to be elevated in the progression of a variety of inflammatory diseases. Therefore, we analyzed the specific roles of DUOX2 in AP development. Blood samples were collected from of AP patients and healthy people, and the caerulein- stimulated human pancreatic duct cells (H6C7) were utilized to establish an AP cell model. Cell growth and apoptosis were measured using an MTT assay and TUNEL staining. Additionally, RT-qPCR and western blot assays were conducted to assess the RNA and protein expressions of the cells. ELISA kits were used to determine TNF-α, IL-6, IL-8, and IL-1β levels. The interaction between DUOX2 and miR-605-3p was predicted using the Targetscan database and confirmed by dual-luciferase report assay. We found that DUOX2 increased while miR-605-3p decreased in the blood of AP patients and caerulein-stimulated H6C7 cells. DUOX2 was targeted by miR-605-3p. Furthermore, DUOX2 knockdown or miR-605-3p overexpression promoted cell viability, decreased the TNF-α, IL-6, IL-8, and IL-1β levels, and inhibited apoptosis rate in caerulein-stimulated H6C7 cells. DUOX2 knockdown or miR-605-3p overexpression also increased the Bcl-2 protein levels and down-regulated Bax, cleaved-caspase-1, NLRP3 and p-p65. Interestingly, DUOX2 overexpression reversed the miR-605-3p mimic function in the caerulein-treated H6C7 cells. In conclusion, our research demonstrated that DUOX2 knockdown relieved the injury and inflammation in caerulein-stimulated H6C7 cells.

Involvement of circ_0029407 in Caerulein-Evoked Cytotoxicity in Human Pancreatic Cells via the miR-579-3p/TLR4/NF-κB Pathway

Acute pancreatitis (AP) is the most prevalent gastrointestinal inflammatory disease. Circular RNAs (circRNAs) are implicated in the development of AP. Here, we identified the precise action of circ_0029407 in AP development. Human pancreatic epithelial cells (HPECs) were stimulated with caerulein. Cell viability, proliferation, and apoptosis were gauged by Cell Counting Kit-8 (CCK-8), 5-ethynyl-2'-deoxyuridine (EdU), and flow cytometry assays, respectively. Circ_0029407, microRNA (miR)-579-3p, and toll-like receptor 4 (TLR4) were quantified by a qRT-PCR or western blot assay. Dual-luciferase reporter and RNA pull-down assays were performed to evaluate the direct relationship between miR-579-3p and circ_0029407 or TLR4. Our results indicated that circ_0029407 was markedly overexpressed in AP serum samples and caerulein-stimulated HPECs. Reduction of circ_0029407 attenuated caerulein-imposed HPEC damage by promoting cell proliferation and repressing cell apoptosis and inflammation. Mechanistically, circ_0029407 contained a miR-579-3p binding site, and miR-579-3p downregulation reversed the effect of circ_0029407 reduction on caerulein-imposed HPEC damage. TLR4 was identified as a direct and functional target of miR-579-3p, and TLR4 overexpression reversed the impact of miR-579-3p upregulation on attenuating caerulein-imposed HPEC damage. Moreover, circ_0029407 regulated the TLR4/nuclear factor NF-kappaB (NF-κB) signaling by acting as a competing endogenous RNA (ceRNA) for miR-579-3p. Our study suggests that circ_0029407 regulates caerulein-imposed cell injury in human pancreatic cells at least in part via the TLR4/NF-κB signaling pathway by functioning as a ceRNA for miR-579-3p.

Demotion of canonical/non-canonical inflammasome and pyroptosis alleviates ischemia/reperfusion-induced acute kidney injury: Novel role of the D2/D3 receptor agonist ropinirole

Ropinirole used to treat Parkinson's disease highly targets the dopaminergic receptor D3 over the D2 receptor but although both are expressed in the kidneys the ropinirole potential to treat kidney injury provoked by ischemia/reperfusion (I/R) is undraped. We investigated whether ropinirole can alleviate renal I/R by studying its anti-inflammatory, antioxidant, and anti-pyroptotic effects targeting its aptitude to inhibit the High-mobility group box 1/Toll-like receptor 4/Nuclear factor-kappa B (HMGB1/TLR4/NF-κB) cue and the canonical/non-canonical NOD-like receptor family pyrin domain containing 3 (NLRP3) inflammasome trajectories. Herein, bilateral I/R surgery was induced in animals to be either untreated or treated with ropinirole for three days after the insult. Ropinirole successfully improved the histopathological picture and renal function which was confirmed by reducing cystatin C and the standard parameters creatinine and blood urea nitrogen (BUN). Ropinirole achieved this through its anti-inflammatory capacity mediated by reducing the HMGB1/TLR4 axis and inactivating NF-κB, which are upstream regulators of the NLRP3 pathway. As a result, the injurious inflammasome markers (NLRP3, apoptosis-associated speck-like protein (ASC), active caspase-1) and their target cytokines interleukin-1 beta (IL-1β) and IL-18 were decreased. Ropinirole also reduced the pyroptotic cell death markers caspase-11 and gasdermin-D. Furthermore, ropinirole by replenishing antioxidants and decreasing malondialdehyde helped to reduce oxidative stress in the kidneys. The docking findings confirmed that ropinirole highly binds to the dopaminergic D3 receptor more than to the D2 receptor. In conclusion, ropinirole has the potential to be a reno-therapeutic treatment against I/R insult by abating the inflammatory NLRP3 inflammasome signal, pyroptosis, and oxidative stress.

Pramipexole protects against diabetic neuropathy: Effect on oxidative stress, TLR4/IRAK-1/TRAF-6/NF-κB and downstream inflammatory mediators

BACKGROUND

Diabetic neuropathy (DN) is a serious microvascular complication and a major cause of morbidity and mortality in diabetes mellitus. It is characterized by neurodegeneration of terminal sensory nerve fibers with subsequent pain, loss of sensation, and paresthesia, thus compromising the quality of life of diabetic patients. It is considered the leading cause of non-traumatic amputations worldwide, reflecting the insufficiency of current therapies. Pramipexole (PPX) is a dopamine receptor agonist used for the treatment of Parkinson's disease. The current study aims to investigate the potential neuroprotective effect of PPX in an experimental model of DN.

METHODS

Sprague Dawley rats were randomly assigned into five groups: normal control, Normal + PPX (1 mg/kg) group, STZ control, STZ + PPX (0.25 and 1 mg/kg/day for eight weeks). The neuroprotective effect of PPX in rats was evaluated in terms of sciatic nerve histological alterations, oxidative stress, and protein expression of TLR4/MyD88/IRAK-1/TRAF-6/NF-κB axis and downstream inflammatory mediators.

RESULTS

PPX administration ameliorated histopathological signs of neuronal inflammation and apoptosis. Additionally, PPX attenuated STZ-induced sciatic nerve oxidative stress and downregulated neural tissue expression of TLR4, MyD88, IRAK-1, TRAF-6, NF-κB and downstream mediators (TNF-α, IL-1β and ICAM-1).

CONCLUSION

Collectively, the current study sheds light on PPX as a potential protective medication to alleviate neuropathy progression in diabetic patients. PPX neuroprotective effect can be attributed to modulating TLR4/ MyD88/IRAK-1/TRAF-6/ NF-κB axis signaling in nerve tissues with subsequent attenuation of oxidative stress and inflammation.

The FDA-approved compound, pramipexole and the clinical-stage investigational drug, dexpramipexole, reverse chronic allodynia from sciatic nerve damage in mice, and alter IL-1β and IL-10 expression from immune cell culture

During the onset of neuropathic pain from a variety of etiologies, nociceptors become hypersensitized, releasing neurotransmitters and other factors from centrally-projecting nerve terminals within the dorsal spinal cord. Consequently, glial cells (astrocytes and microglia) in the spinal cord are activated and mediate the release of proinflammatory cytokines that act to enhance pain transmission and sensitize mechanical non-nociceptive fibers which ultimately results in light touch hypersensitivity, clinically observed as allodynia. Pramipexole, a D2/D3 preferring agonist, is FDA-approved for the treatment of Parkinson's disease and demonstrates efficacy in animal models of inflammatory pain. The clinical-stage investigational drug, R(+) enantiomer of pramipexole, dexpramipexole, is virtually devoid of D2/D3 agonist actions and is efficacious in animal models of inflammatory and neuropathic pain. The current experiments focus on the application of a mouse model of sciatic nerve neuropathy, chronic constriction injury (CCI), that leads to allodynia and is previously characterized to generate spinal glial activation with consequent release IL-1β. We hypothesized that both pramipexole and dexpramipexole reverse CCI-induced chronic neuropathy in mice, and in human monocyte cell culture studies (THP-1 cells), pramipexole prevents IL-1β production. Additionally, we hypothesized that in rat primary splenocyte culture, dexpramixole increases mRNA for the anti-inflammatory and pleiotropic cytokine, interleukin-10 (IL-10). Results show that following intravenous pramipexole or dexpramipexole, a profound decrease in allodynia was observed by 1 hr, with allodynia returning 24 hr post-injection. Pramipexole significantly blunted IL-1β protein production from stimulated human monocytes and dexpramipexole induced elevated IL-10 mRNA expression from rat splenocytes. The data support that clinically-approved compounds like pramipexole and dexpramipexole support their application as anti-inflammatory agents to mitigate chronic neuropathy, and provide a blueprint for future, multifaceted approaches for opioid-independent neuropathic pain treatment.