ZBP1-mediated PANoptosis: A possible novel mechanism underlying the therapeutic effects of penehyclidine hydrochloride on myocardial ischemia-reperfusion injury.

Although penehyclidine hydrochloride (PHC) has been identified to alleviate myocardial injury induced by ischemia/reperfusion (I/R), the regulatory molecules and related mechanisms are unknown. In this study, bioinformatics, molecular biology, and biochemistry methods were used to explore the molecular mechanisms and targets of PHC. In the myocardial ischemia-reperfusion injury (MIRI)-induced rat model, PHC pretreatment significantly improved cardiac function (p < 0.01). Multiple differentially expressed genes, including Z-DNA binding protein 1 (ZBP1), were identified through mRNA sequencing analysis of myocardial ischemic penumbra tissue in MIRI rats. The transduction of the ZBP1 adenovirus vector (Ad-Zbp1) in PHC-pretreated rats exhibited a reversible augmentation in myocardial infarct size (p < 0.01), pronounced pathological damage to the myocardial tissue, as well as a significant elevation of serum myocardial enzymes (p < 0.05). The interaction among ZBP1, fas-associating via death domain (FADD), and receptor-interacting serine/threonine-protein kinase 3 (RIPK3) leads to a remarkable up-regulation of cleaved-Caspase-1 (Cl-Casp-1), N-terminal gasdermin D (N-GSDMD), phospho-mixed lineage kinase domain-like Ser358 (p-MLKLS358), and other regulatory proteins, thereby triggering pyroptosis, apoptosis, and necroptosis (PANoptosis) in cardiomyocytes of MIRI rats. Moreover, the transduction of Ad-Zbp1 in the oxygen-glucose deprivation/re-oxygenation (OGD/R)-induced H9c2 cell model also dramatically augmented the number of cell deaths. However, the intervention of PHC considerably enhanced cell viability (p < 0.01), effectively mitigated the release of myocardial enzymes (p < 0.05), and markedly attenuated the expression levels of PANoptosis regulatory proteins through restraint of ZBP1 expression. Therefore, the therapeutic efficacy of PHC in improving MIRI might be attributed to targeting ZBP1-mediated PANoptosis.

A New Aspect of Penehyclidine Hydrochloride in Alleviating Myocardial Ischemia-Reperfusion Injury: Ferroptosis.

Penehyclidine hydrochloride (PHC) is an anticholinergic drug with cardioprotective effects. Ferroptosis is closely related to myocardial ischaemia-reperfusion injury (MIRI). In the present study, MIRI was induced in rats by left anterior descending coronary artery ligation. PHC pretreatment increased haemodynamic parameters and histopathological damage and reduced myocardial infarction size in the MIRI model. PHC pretreatment also inhibited ferroptosis, which was characterized by the decreased levels of Fe2+, 4-hydroxynonenal and ACSL4, and increased levels of GPX4, GSH-Px and GST. In response to 6 h of oxygen-glucose deprivation and 18 h of reoxygenation, PHC pretreatment had the same effects on these factors in H9c2 cells and reduced lipid ROS levels. Furthermore, ACSL4 overexpression reversed the protective effects of PHC on H9c2 cells. These results indicated that PHC inhibited MIRI through ACSL4-mediated ferroptosis. This study demonstrated that PHC could inhibit ferroptosis in MIRI and the relationship among PHC, ACSL4, ferroptosis and MIRI. This study demonstrated the inhibitory effect of PHC on ferroptosis and showed that PHC affects MIRI through ACSL4-mediated ferroptosis in vivo and in vitro.

BTP2, a Store-Operated Calcium Channel Inhibitor, Attenuates Lung Ischemia-Reperfusion Injury in Rats.

Lung ischemia-reperfusion (I/R) injury is a critical complication following a lung transplant, cardiopulmonary bypass, pulmonary embolism, and trauma. Immune cells and their effector functions are involved in the lung I/R injury. Store-operated calcium channels (SOCC) are highly Ca2+-selective cation channels and have crucial effects on the immune system. It has been indicated that BTP2, a potent SOCC blocker, could inhibit pro-inflammatory cytokine production from immune cells both in vitro and in vivo. Therefore, this study was conducted to investigate the beneficial effects of BTP2 on lung I/R injury in Sprague-Dawley (SD) rats. The left lungs of male SD rats underwent ischemia for 60 min and reperfusion for 2 h. Treated animals received BTP2 4 mg/kg or 10 mg/kg intraperitoneally 30 min before the ischemia. The results revealed that pretreatment with BTP2 markedly attenuated I/R injury-induced pulmonary edema, microvascular protein leakage, neutrophil infiltration, adhesion molecules, cytokine production (e.g., ICAM-1, TNF-α, IL-1ß, and IL-2), and the transcription factor nuclear factor of activated T cells c1 nuclear translocation in the lung tissue. These findings indicate that BTP2 can be a potential therapeutic drug for lung I/R injury and suggest that SOCC may play a critical role in lung I/R injury.

The Central Analgesic Mechanism of YM-58483 in Attenuating Neuropathic Pain in Rats.

Calcium channel antagonists are commonly used to treat neuropathic pain. Their analgesic effects rely on inhibiting long-term potentiation, and neurotransmitters release in the spinal cord. Store-operated Ca(2+)channels (SOCCs) are highly Ca(2+)-selective cation channels broadly expressed in non-excitable cells and some excitable cells. Recent studies have shown that the potent inhibitor of SOCCs, YM-58483, has analgesic effects on neuropathic pain, but its mechanism is unclear. This experiment performed on spinal nerve ligation (SNL)-induced neuropathic pain model in rats tries to explore the mechanism, whereby YM-58483 attenuates neuropathic pain. The left L5 was ligated to produce the SNL neuropathic pain model in male Sprague-Dawley rats. The withdrawal threshold of rats was measured by the up-down method and Hargreaves' method before and after intrathecal administration of YM-58483 and vehicle. The SOCCs in the spinal dorsal horn were located by immunofluorescence. The expression of phosphorylated ERK and phosphorylated CREB, CD11b, and GFAP proteins in spinal level was tested by Western blot, while the release of proinflammatory cytokines (IL-1ß, TNF-α, PGE2) was measured by enzyme-linked immunosorbent assay (ELISA). Intrathecal YM-58483 at the concentration of 300 µM (1.5 nmol) and 1000 µM (10 nmol) produced a significant central analgesic effect on the SNL rats, compared with control + vehicle (n = 7, P < 0.001). However, both could not prevent the development of neuropathic pain, compared with normal + saline (P < 0.001). Immunofluorescent staining revealed that Orai1 and STIM1 (the two key components of SOCCs) were located in the spinal dorsal horn neurons. Western blot showed that YM-58483 could decrease the levels of P-ERK and P-CREB (n = 10, #P < 0.05), without affecting the expression of CD11b and GFAP (n = 10, #P > 0.05). YM-58483 also inhibited the release of spinal cord IL-1ß, TNF-α, and PGE2, compared with control + vehicle (n = 5, #P < 0.001). The analgesic mechanism of YM-58483 may be via inhibiting central ERK/CREB signaling in the neurons and decreasing central IL-1ß, TNF-α, and PGE2 release to reduce neuronal excitability in the spinal dorsal horn of the SNL rats.

Imprinted-like biopolymeric micelles as efficient nanovehicles for curcumin delivery.

To enhance the solubility and improve the bioavailability of hydrophobic curcumin, a new kind of imprinted-like biopolymeric micelles (IBMs) was designed. The IBMs were prepared via co-assembly of gelatin-dextran conjugates with hydrophilic tea polyphenol, then crosslinking the assembled micelles and finally removing the template tea polyphenol by dialysis. The obtained IBMs show selective binding for polyphenol analogous drugs over other drugs. Furthermore, curcumin can be effectively encapsulated into the IBMs with 5×10(4)-fold enhancement of aqueous solubility. We observed the sustained drug release behavior from the curcumin-loaded IBMs (CUR@IBMs) in typical biological buffers. In addition, we found the cell uptake of CUR@IBMs is much higher than that of free curcumin. The cell cytotoxicity results illustrated that CUR@IBMs can improve the growth inhibition of HeLa cells compared with free curcumin, while the blank IBMs have little cytotoxicity. The in vivo animal study demonstrated that the IBMs could significantly improve the oral bioavailability of curcumin.

Effect of dexmedetomidine on lung ischemia­reperfusion injury.

Dexmedetomidine, a specific selective α2-adrenergic agonist, does not only have the characteristics of being a sedative and analgesic, but also exhibits a protective role in brain ischemia-reperfusion injury and inhibits the inflammation in animals with sepsis. The objective of the present study was to investigate whether dexmedetomidine is capable of attenuating rat pulmonary damage induced by ischemia-reperfusion injury, which is a type of acute sterile lung injury. Sprague-Dawley rats were randomly assigned into six groups: The sham-operated (sham) group, the lung ischemia-reperfusion (I/R) group, intravenous injection of dexmedetomidine 2.5 µg/kg/h (Dex2.5) or 5 µg/kg/h (Dex5) for 1 h prior to ischemia, combination of α2-adrenergic antagonist yohimbine prior to dexmedetomidine pre-treatment (Dex+Yoh) and pre-administration of yohimbine alone (Yoh) prior to ischemia. Lung injury was assessed by the histopathological changes, arterial blood gas, wet/dry (w/d) weight ratio and myeloperoxidase (MPO) activity of the lung. The concentration of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and monocyte chemoattractant protein-1 (MCP-1) in bronchoalveolar lavage fluid (BALF) was measured by an enzyme-linked immunosorbent assay. The expression of toll-like receptor-4 (TLR4) and myeloid differentiation factor 88 (MyD88) mRNA in the lung were determined by quantitative PCR, and phosphorylated levels of c-Jun N-terminal kinase (JNK) and extracellular signal-regulated kinase (ERK)1/2 were determined by western blotting. Pre-treatment with dexmedetomidine significantly reduced the lung injury, w/d weight ratio and MPO activity, and decreased the concentration of TNF-α, IL-6 and MCP-1 in BALF compared with the I/R group. The expression of TLR4 and MyD88 mRNA and the levels of phosphorylated JNK and ERK1/2 in the lung tissue were markedly downregulated by intravenous injection of dexmedetomidne for 1 h prior to lung I/R. The protective effects of dexmedetomidine on the lung were not completely reversed by the α2-adrenergic antagonist, yohimbine. Pre-treatment with dexmedetomidine is capable of reducing pulmonary damage and inhibiting sterile inflammation induced by lung I/R injury. TLR4/MyD88/mitogen-activated protein kinase (MAPK) signaling is involved in the protective mechanism of dexmedetomidine through α2-adrenoceptor independence.

[Effect of dexmedetomidine hydrochloride on H2O2-induced oxidative stress in alveolar macrophages].

OBJECTIVE: To evaluate whether dexmedetomidine hydrochloride, an α2-adrenergic receptor agonist, can prevent oxidative damage to alveolar macrophages induced by H2O2. METHODS: We used methyl thiazolyl tetrazolium (MTT) colorimetry to test the effect of different concentrations and action time of H2O2 on the survival rate of alveolar macrophages, and then we chose the appropriate H2O2 concentration and action time to build NR8383 cell oxidative damage model. After pre-conditioning of 0.01, 0.10, and 1.00 µmol/L dexmedetomidine hydrochloride for 24 hours, MTT colorimetry was used to demonstrate the survival rate of NR8383 cells damaged by H2O2, and the release of lactate dehydrogenase (LDH) and TNF-α by H2O2-damaged NR8383 cells was detected by corresponding kit. RESULTS: At 50-300 µmol/L, H2O2 caused concentration-dependent oxidative damage in the alveolar macrophages, decreased the cell survival rate, and increased LDH and TNF-α release. At 0.01-1.00 µmol/L dexmedetomidine hydrochloride concentration-dependently protected NR8383 cells from oxidative damage induced by H2O2, significantly increased the cell survival rate, decreased LDH and TNF-α release, and this effect of dexmedetomidine hydrochloride was dose-dependent. Yohimbine, an α2 - adrenergic receptor antagonist, completely neutralized the protective effect of dexmedetomidine hydrochloride on NR8383 cells without affecting the oxidative damage of NR8383 cells. CONCLUSION: Dexmedetomidine hydrochloride can prevent alveolar macrophages from oxidative damage induced by H2O2, which may play a protective role through α2 - adrenergic receptors.