IL-6 x RIPK3

The mechanism underlying necroptosis in pulmonary vessel endothelial cells (PVECs) resulting from long non-coding RNA (lncRNA)-induced alternative splicing (AS) of target genes in acute lung injury (ALI) remains unclear.

Lipopolysaccharide (LPS)-induced expression of tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6, and lncRNAs was analyzed via RT-PCR in PVECs. Full-transcriptome sequencing was used to detect AS-related mRNAs. The interaction between lncRNA MALAT1 and target gene transmembrane BAX inhibitor motif-containing 6 (TMBIM6) was verified using a dual-luciferase reporter system. Necroptosis was measured as protein levels of phosphorylated receptor-interacting serine/threonine kinase 1 (RIPK1), RIPK3, and mixed-lineage kinase domain-like (MLKL) proteins, as well as flow cytometer measurement. Antisense of MALAT1, TMBIM6, TMBIM6-225 and RIPK1 inhibitor were transfected into a rat model of LPS-induced ALI. Hematoxylin and eosin (H&E) and immunohistochemical staining were performed to evaluate lung injury.

LPS upregulated the expression of TNF-α, IL-1β, IL-6, p-RIPK1, p-RIPK3, p-MLKL, MALAT1, and TMBIM6-225 (an AS isoform of MALAT1-targeted gene TMBIM6) in PVECs. However, it downregulated the expression of TMBIM6. An antisense of MALAT1 inhibited TMBIM6-225 and downregulated p-MLKL. The pro-necroptotic effect of MALAT1 was verified in an LPS-induced MALAT1/shMALAT1-transfected ALI rat model in vivo. The necroptotic effect was reversed by treatment with necrostatin-1.

LPS-induced MALAT1 causes AS of TMBIM6, and the AS variant TMBIM6-225 aggravates ALI by promoting PVEC necroptosis via the p-RIPK1, p-RIPK3, and p-MLKL complex.

Cognitive dysfunction is the most severe non-motor symptom of Parkinson's disease (PD). Our previous study revealed that hydrogen sulfide (H₂S) ameliorates cognitive dysfunction in PD, but the underlying mechanisms remain unclear. Hippocampal necroptosis plays a vital role in cognitive dysfunction, while the cGAS/STING pathway triggers necroptosis. To understand the mechanism underlying the inhibitory role of H₂S in cognitive dysfunction of PD, we explored whether H₂S reduces the enhancement of necroptosis and the activation of the cGAS/STING pathway in the hippocampus of the rotenone (ROT)-induced PD rat model.

Adult Sprague-Dawley (SD) rats were pre-treated with NaHS (30 or 100 μmol/kg/d, i.p.) for 7 days and then co-treated with ROT (2 mg/kg/d, s.i.) for 35 days. The Y-maze and Morris water maze (MWM) tests were used to assess the cognitive function. Hematoxylin-eosin (H&E) staining was used to detect the hippocampal pathological morphology. Western blotting analysis was used to measure the expressions of proteins. Enzyme-linked immunosorbent assay was used to determine the levels of inflammatory factors.

NaHS (a donor of H₂S) mitigated cognitive dysfunction in ROT-exposed rats, according to the Y-maze and MWM tests. NaHS treatment also markedly down-regulated the expressions of necroptosis-related proteins (RIPK1, RIPK3, and MLKL) and decreased the levels of necroptosis-related inflammatory factors (IL-6 and IL-1β) in the hippocampus of ROT-exposed rats. Furthermore, NaHS treatment reduced the expressions of cGAS/STING pathway-related proteins (cGAS, STING, p-TBK1^Ser172, p-IRF3^Ser396, and p-P65^Ser536) and decreased the contents of pro-inflammation factors (INF-β and TNF-α) in the hippocampus of ROT-exposed rats.

H₂S attenuates the cGAS/STING pathway-triggered necroptosis in the hippocampus, which is related to H₂S to attenuate cognitive dysfunction in PD.

Impaired autophagy is implicated in the pathogenesis of caerulein-induced model of acute pancreatitis (AP). Chloroquine blocks the fusion of autophagosome and lysosome and affects completion of the cellular autophagic flux. Adult, male, Swiss albino mice (20-25 g) were divided into four groups- 1, 2, 3 and 4 of 6 mice each. Mice in Group1 were given 8, hourly intraperitoneal injections of normal saline. Group 2 was also given intraperitoneal injections of chloroquine (60 mg/Kg) at 14 h and 30-min prior to first injection of normal saline. Mice in Groups 3 and 4 given 8, hourly intraperitoneal injections of caerulein (50 µg /Kg/dose). Group 4 also received chloroquine as Group 2. After sacrifice at the 9th hour in CO₂-chamber, blood was drawn for amylase activity and cytokines estimation (IL-6, TNF-α, GM-CSF, IL-1β and IL-10) and pancreas was harvested for histopathology, transmission electron microscopy (TEM) and immunoblotting (LC3II, Beclin 1, SQSTM1, RIPK1, P65, Caspase-3, RIPK3, HMGB1). The relative expression of SQSTM1 and the autophagic vacuole area was higher in groups 2, 3 and 4 (p < 0.05), suggestive of increased impairment of autophagic flux. Autolysosome count was significantly increased in group 3 in comparison to group 1 (p = 0.0049). Autolysosome area was also increased in group 4 in comparison to group 3 (p = 0.031), which suggested impairment of autophagy. Total histopathological score and amylase activity were equivalent in groups 3 and 4. RIPK1 in pancreas and TNF-α level in plasma were more in group 4 than 3 (p = 0.014, 0.02, respectively). Expression of Caspase-3, was lesser in group 4 than 3 (p < 0.001). Expression of HMGB1was more in group 4 than 3 (p = 0.046). Chloroquine enhances necrosis and inflammation in caerulein-induced pancreatitis.