Differential heating of trunk and extremities. Effects on thermoregulation mechanisms

Experiments in which the whole human body was heated or cooled are compared with others in which one extremity (arm or leg) was simultaneously cooled or heated. With a warm load on the rest of the body resulting in general sweating, a cold load on one extremity did not evoke local shivering; with general body cooling, heating one limb did not stop the shivering. Skin temperatures of the other parts of the body were not influenced by warming or cooling one extremity. Evaporative heat loss was influenced by local, mean skin and core temperature, whereas shivering did not depend on local temperature, and vasomotor control seemed to be controlled predominantly by central temperatures. A cold load on an extremity during whole body heating in most cases induced an oscillatory behaviour of core temperature and of the evaporative heat loss from the body and the extremity. It is assumed that local, mean skin and core temperatures influence the three autonomous effector systems to very different degree.     

Complement induces podocyte pyroptosis in membranous nephropathy by mediating mitochondrial dysfunction

Podocyte damage mediated by in situ complement activation in the glomeruli is a key factor in the pathogenesis of membranous nephropathy (MN), but the molecular mechanism has not been fully elucidated. Pyroptosis is a special type of programmed cell death, mediate inflammatory response and induce tissue injury. However, it is not clear whether pyroptosis is involved in the development and progression of MN. Here, we report that pyroptosis plays an important role in promoting podocyte injury in MN. We first observed the occurrence of pyroptosis in the kidneys of MN patients and validated that complement stimulation triggered pyroptosis in podocytes and that inhibiting pyroptosis reversed complement-induced podocyte damage in vitro. In addition, stimulation of complement caused mitochondrial depolarization and reactive oxygen species (ROS) production in podocytes, and inhibition of ROS reversed complement-induced pyroptosis in podocytes. Interestingly, inhibition of pyroptosis in turn partially alleviated these effects. Furthermore, we also found the involvement of pyroptosis in the kidneys of passive Heymann nephritis (PHN) rats, and inhibitors of pyroptosis-related molecules relieved PHN-induced kidney damage in vivo. Our findings demonstrate that pyroptosis plays a critical role in complement-induced podocyte damage in MN and mitochondrial dysfunction is an important mechanism underlying this process. It provides new insight that pyroptosis may serve as a novel therapeutic target for MN treatment in future studies.Subject terms: Cell death, Membranous nephropathy     

The combination of Panax ginseng and Angelica sinensis alleviates ischemia brain injury by suppressing NLRP3 inflammasome activation and microglial pyroptosis

BackgroundThe combination of Panax ginseng and Angelica sinensis (CPA) has been used to treat stroke for one thousand years and demonstrated clinically to have satisfied effects. However, the underlying mechanism remains unknown.PurposeWe investigate whether CPA has neuroprotective effects via suppressing Nod-like receptor protein 3 (NLRP3) inflammasome and microglial pyroptosis against ischemic injury in transient middle cerebral artery occlusion (MCAO) rats.MethodsMale rats were divided randomly into sham operated, MCAO, MCC950 (NLRP3-specific inhibitor) and CPA groups. Neurological deficits, glucose uptake, infarct size, activation of NLRP3 inflammasomes, microglial pyroptosis and related signaling pathways were detected. BV-2 microglial cells subjected to oxygen-glucose deprivation/reoxygenation (OGD/R) were used in in vitro experiments.ResultsCompared with sham rats, elevated level of proinflammatory interleukin-1β (IL-1β) in plasma, neurological function deficit, reduced glucose uptake in ipsilateral hemisphere, obvious infarct size, the activation of NLRP3 inflammasomes and enhanced microglial pyroptosis were presented in MCAO rats. The administrations of MCC950 and CPA respectively reversed the results. In vitro OGD/R induced the release of lactate dehydrogenase, promoted NLRP3 inflammasomes activation and pyroptosis in BV-2 cells, which was significantly suppressed by treatment with ginsenoside Rd (Rd) and Z-ligustilide (LIG). Mechanistically, OGD/R induced high expression of dynamin-related protein 1 (Drp1) and mitochondrial fission, as well as NLRP3 inflammasomes activation and pyroptosis in BV-2 cells, which was attenuated by treatment with Rd and LIG. Moreover, the increased expression of Drp1 was validated in MCAO rats, and also abolished by MCC950 or CPA treatments.ConclusionCPA treatment attenuates cerebral injury via inhibition of NLRP3 inflammasomes activation and microglial pyroptosis after stroke, which at least partially involved in the amelioration of Drp1-mediated mitochondrial fission.     

Activating Nrf-2 Signaling Depresses Unilateral Ureteral Obstruction-Evoked Mitochondrial Stress-Related Autophagy,Apoptosis and Pyroptosis in Kidney

Exacerbated oxidative stress and inflammation may induce three types of programmed cell death, autophagy, apoptosis and pyroptosis in unilateral ureteral obstruction (UUO) kidney. Sulforaphane activating NF-E2-related nuclear factor erythroid-2 (Nrf-2) signaling may ameliorate UUO-induced renal damage. UUO was induced in the left kidney of female Wistar rats. The level of renal blood flow, cortical and medullary oxygen tension and reactive oxygen species (ROS) was evaluated. Fibrosis, ED-1 (macrophage/monocyte) infiltration, oxidative stress, autophagy, apoptosis and pyroptosis were evaluated by immunohistochemistry and Western blot in UUO kidneys. Effects of sulforaphane, an Nrf-2 activator, on Nrf-2- and mitochondrial stress-related proteins and renal injury were examined. UUO decreased renal blood flow and oxygen tension and increased renal ROS, 3-nitrotyrosine stain, ED-1 infiltration and fibrosis. Enhanced renal tubular Beclin-1 expression started at 4 h UUO and further enhanced at 3d UUO, whereas increased Atg-5-Atg12 and LC3-II expression were found at 3d UUO. Increased renal Bax/Bcl-2 ratio, caspase 3 and PARP fragments, apoptosis formation associated with increased caspase 1 and IL-1β expression for pyroptosis formation were started from 3d UUO. UUO reduced nuclear Nrf-2 translocation, increased cytosolic and inhibitory Nrf-2 expression, increased cytosolic Bax translocation to mitochondrial and enhanced mitochondrial Cytochrome c release into cytosol of the UUO kidneys. Sulforaphane significantly increased nuclear Nrf-2 translocation and decreased mitochondrial Bax translocation and Cytochrome c release into cytosol resulting in decreased renal injury. In conclusion, sulforaphane via activating Nrf-2 signaling preserved mitochondrial function and suppressed UUO-induced renal oxidative stress, inflammation, fibrosis, autophagy, apoptosis and pyroptosis.     

In vivo mechanisms of cutaneous vasodilation and vasoconstriction in humans during thermoregulatory challenges.

This review focuses on the neural and local mechanisms that have been demonstrated to effect cutaneous vasodilation and vasoconstriction in response to heat and cold stress in vivo in humans. First, our present understanding of the mechanisms by which sympathetic cholinergic nerves mediate cutaneous active vasodilation during reflex responses to whole body heating is discussed. These mechanisms include roles for cotransmission as well as nitric oxide (NO). Next, the mechanisms by which sympathetic noradrenergic nerves mediate cutaneous active vasoconstriction during whole body cooling are reviewed, including cotransmission by neuropeptide Y (NPY) acting through NPY Y1 receptors. Subsequently, current concepts for the mechanisms that effect local cutaneous vascular responses to direct skin warming are examined. These mechanisms include the roles of temperature-sensitive afferent neurons as well as NO in causing vasodilation during local heating of skin. This section is followed by a review of the mechanisms that cause local cutaneous vasoconstriction in response to direct cooling of the skin, including the dependence of these responses on intact sensory and sympathetic, noradrenergic innervation as well as roles for nonneural mechanisms. Finally, unresolved issues that warrant further research on mechanisms that control cutaneous vascular responses to heating and cooling are discussed.     

A Comparative Test of Mechanized and Manual Transplanting of Eelgrass, Zostera marina, in Chesapeake Bay

Abstract The laborious process of manual seagrass transplanting has often limited the size of seagrass restoration efforts. This study tested the efficiency of a mechanized planting boat, previously used for transplanting Halodule wrightii, relative to manual transplanting methods for establishing Zostera marina in Chesapeake Bay. Eelgrass planting was conducted at two sites, one each in the Rappahannock and James rivers, in October 2001. The methods were evaluated by three criteria: (1) initial planting success = proportion of attempted planting units (PUs) initially established (number confirmed in sediment by divers/number attempted); (2) survival = proportion of the initially established PUs persisting over 1, 4, and 24 weeks; and (3) efficiency = labor (in person·seconds) invested in each surviving PU. Initial planting success was significantly lower for the planting boat (24 and 56% at the Rappahannock and James sites, respectively) than for manual transplanting (100% at both sites). At the Rappahannock site, survival of initially established PUs declined over time for both methods, but while mean survival was always higher for manually planted rows, differences in survival between methods were not statistically significant. At the James site, survival to 1 and 4 weeks was significantly lower for the machine than for the manual method, but survival to 24 weeks was not significantly different. While the machine was able to attempt PUs faster than the manual method (2.2 s/PU vs. 5.8 s/PU, respectively), this speed was offset by poorer planting success rates, resulting in a much greater total labor investment for each machine‐planted PU that persisted to 24 weeks than for each similarly persisting manually planted PU (40.6 person·seconds/PU and 22.4 person·seconds/PU, respectively, averaged across sites). In summary, those PUs successfully planted by the machine survived similarly to PUs planted by hand, but as a result of poorer initial planting success, the machine required a greater investment of labor and plant donor stock for each PU surviving to 24 weeks. Therefore, in its tested configuration this planting boat is not a significant improvement over the manual method for transplanting eelgrass.     

红茶菌在脑缺血再灌注损伤大鼠模型中的作用研究

摘要 目的：探讨红茶菌在脑缺血再灌注损伤大鼠模型中是否有改善效果。方法：将48只清洁级SD大鼠根据随机数字表法分为假手术组、模型组、红茶菌组、依达拉奉组。红茶菌组术前给予红茶菌液灌胃7天以及再灌注麻醉清醒后追加灌胃1次,依达拉奉组大鼠在再灌注前15 min经腹腔注射依达拉奉,模型组和假手术组给予生理盐水。遵循Zea Longa线栓法阻断大鼠大脑中动脉血流2 h后恢复再灌注24 h 建立MCAO模型,假手术组大鼠仅分离劲总动脉。再灌注24 h后,神经行为学评分评估脑损伤程度;TTC染色观察红茶菌对大鼠脑梗死面积比的影响并用Image J软件测定梗死面积;HE染色后观察大鼠脑组织皮层神经元病理形态学;透射电镜观察大鼠皮层神经元超微结构及线粒体形态。结果：脑缺血再灌注24 h后,对大鼠进行神经行为学评分,红茶菌组神经神经行为学评分为（2.21±0.60）,依达拉奉组神经行为学评分为（2.01±0.66）,均显著低于模型组（2.52±0.52）（P＜0.05）;TTC染色后观察到模型组大鼠大脑梗死灶明显,红茶菌组与依达拉奉组较模型组大鼠梗死面积明显减小;HE结果显示模型组大脑皮层神经元损伤明显,红茶菌组与依达拉奉组较模型组大脑皮层神经元坏死减轻,梗死面积缩小;透射电镜下观察到模型组大鼠染色质溶解,线粒体肿胀,红茶菌组与依达拉奉组较模型组溶解减少,线粒体结构较完整。结论：红茶菌可减轻脑缺血再灌注损伤大鼠模型的神经元损伤,有望成为改善脑缺血再灌注损伤的疗法或辅助疗法。     

DTX3L induced NLRP3 ubiquitination inhibit R28 cell pyroptosis in OGD/R injury

Ischemia/reperfusion (I/R) injury is one of the most common etiologies in many diseases. Retinal I/R leads to cytokine storm, resulting in tissue damage and cell death. Pyroptosis, a novel type of regulated cell death, occurs after cellular I/R injury. In this study, we established an oxygen glucose deprivation (OGD/R) cellular model (R28) to simulate retinal I/R injury. We conducted an LDH assay, and EthD-III and PI staining procedures to confirm pyroptosis. Mass spectrometry and bioinformatics analysis were used to identify the possible proteins interacting with NLRP3. Co-IP and various molecular biology techniques were used to investigate the possible modes regulating NLRP3 by DTX3L. EthD-III, PI staining and LDH assays demonstrated pyroptosis induced by OGD/R injury, mediated via NLRP3 pathway. Mass spectrometry and bioinformatics analysis screened out three candidate proteins interacting with NLRP3, and further Co-IP experiment indicated that DTX-3L may interact with NLRP3 to regulate its protein levels after injury. Co-IP experiments and various molecular biology methods demonstrated that DTX3L ubiquitinates NLRP3 resulting in pyroptosis after R28 OGD/R injury. Further, NLRP3 LRR and DTX3L RING domains interact with each other. Our study demonstrated that DTX3L may ubiquitinate NLRP3 to regulate OGD/R-induced pyroptosis globally in R28 cells.     

MSC derived EV loaded with miRNA-22 inhibits the inflammatory response and nerve function recovery after spinal cord injury in rats

Our previous research has found that miRNA-22 can inhibit the occurrence of pyroptosis by targeting GSDMD and decrease the production and release of inflammatory factors. In consideration of the therapeutic effects of mesenchymal stem cells (MSCs), MSCs-EV were loaded with miRNA-22 (EV-miRNA-22) to investigate the inhibitory effect of EV-miRNA-22 on the inflammatory response in SCI in rats in this study. LPS/Nigericin (LPS/NG) was used to induce pyroptosis in rat microglia in vitro. Propidium iodide (PI) staining was performed to observe cell permeability, lactate dehydrogenase (LDH) release assay was adopted to detect cytotoxicity, flow cytometry was conducted to detect pyroptosis level, immunofluorescence (IF) staining was utilized to observe the expression level of GSDMD (a key protein of pyroptosis), Western blot was performed to detect the expression of key proteins. For animal experiments, the T10 spinal cord of rats was clamped by aneurysm clip to construct the SCI model. BBB score, somatosensory evoked potential (SEP) and motor evoked potential (MEP) were performed to detect nerve function. HE staining and Nissl staining were used to detect spinal cord histopathology and nerve cell damage. EV-miRNA-22 could inhibit the occurrence of pyroptosis in microglia, suppress the cell membrane pore opening, and inhibit the release of inflammatory factors and the expression of GSDMD. In addition, EV-miRNA-22 showed higher pyroptosis-inhibiting ability than EV. Consequently, EV-miRNA-22 could inhibit the nerve function injury after SCI in rats, inhibit the level of inflammatory factors in the tissue and the activation of microglia. In this study, we found that miRNA-22-loaded MSCs-EV (EV-miRNA-22) could cooperate with EV to inhibit inflammatory response and nerve function repair after SCI.     

Cardioprotective activity of ethyl acetate extract of Cinnamomi Ramulus against myocardial ischemia/reperfusion injury in rats via inhibiting NLRP3 inflammasome activation and pyroptosis

BackgroundNLRP3 inflammasome activation and pyroptosis play an important role in myocardial ischemia/reperfusion injury (MI/RI). Cinnamomi ramulus (CR), is an important folk medicinal plant in China, which derived from the dried twig of Cinnamomum cassia (L.) Presl, has function of “warming and tonifying heart yang”, and traditionally utilized to treat the cold, blood-cold amenorrhea, phlegm, edema, arthralgia, and palpitations as well as improve blood circulation. The aqueous extract of C. ramulus was reported to show significant therapeutic potential for treating MI/RI. Whereas, there are no previous investigations in China or abroad has reported the cardioprotective effects and underlying mechanism of the ethyl acetate extract of C. ramulus (CREAE) and its bioactive substance cinnamic acid (CA) in triggering NLRP3 inflammasome activation and subsequent pyroptosis.PurposeThe present study aimed to assess the cardioprotective function of CREAE and CA against the MI/RI in rats and involved the underlying mechanisms.MethodsThe MI/RI model was established in male SD rats by occlusion of the left anterior descending coronary artery for 30 min followed by reperfusion for 120 min, respectively. The rats were intragastrically administered with CREAE (74 and 37 mg/kg) and CA (45 mg/kg) for 7 successive days before vascular ligation. The cardioprotective effects of CREAE and CA against myocardial injury of rats were detected by HE staining, TTC staining, echocardiograms, and myocardial enzymes detections. Serum levels of inflammatory factors, such as IL-6, IL-1β, and TNF-α, were analyzed by ELISA kits to evaluate the effects of CREAE and CA. The protein and gene expression levels of NLRP3 and the pyroptosis-related factors in heart tissue were conducted by western blot and RT-qPCR.ResultsOur results showed that CREAE and CA decrease myocardial infarct size and improve cardiac function, mitigate myocardial damage, and repress inflammatory response in rats after I/R. Mechanistically, our results revealed that CREAE and CA can dramatically suppress the activation of NLRP3 inflammasome and subsequent cardiomyocyte pyroptosis in myocardial tissues that as evidenced by downregulating the protein and gene expressions of NLRP3, ASC, IL-1β, caspase-1, gasdermin D, and N-terminal GSDMD.ConclusionsOur data indicated that CREAE and CA may attenuate MI/RI through suppression of NLRP3 inflammasome and subsequent pyroptosis-related signaling pathways.     

Variability of heating and cooling rates during radiant heating in a scincid lizard, Egernia cunninghami

Heating rates were significantly greater than cooling rates in Egernia cunninghami. Male lizards had significantly slower cooling rates than females, while heating rates of both sexes were similar. Faster heating and cooling rates were recorded in the earlier months of the 32-week experiment than during the winter season. The effect of infra-red heat intensity on heating and cooling rates was apparent only in the winter months. Painting the animals black retarded the radiant heating rates, rather than enhancing them.     

Reduction of skeletal muscle injury in composite tissue allotransplantation by heat stress preconditioning

Ischemia-reperfusion injury is a dominant factor limiting tissue survival in any microsurgical tissue transplantation, a fact that also applies to allogeneic hand transplantation. The clinical experience of the 12 human hand transplantations indicates that shorter ischemia times result in reduced tissue damage and, ultimately, in better hand function. Heat stress preconditioning and the accompanying up-regulation of the heat shock protein 72 have been shown to reduce the ischemia-reperfusion injury following ischemia of various organs, including organ transplantation. The aim of this study was to reduce the ischemia-reperfusion injury in a model of composite tissue allotransplantation. Allogeneic hind limb transplantations were performed from Lewis (donor) to Brown-Norway rats. Donor rats in group A (n = 10) received a prior heat shock whereas rats in group B (n = 10) did not receive any prior heat shock. Group C served as a control group without transplantation. The transplantations were performed 24 hours after the heat shock, at which time the heat shock protein 72 was shown to be up-regulated. The outcome was evaluated 24 hours after transplantation by nitroblue tetrazolium staining and wet-to-dry weight ratio of muscle slices (anterior tibial muscle). The nitroblue tetrazolium staining showed a significant reduction of necrotic muscle in group A (prior heat shock) (p = 0.005). The wet-to-dry ratio was significantly reduced in group A (prior heat shock), indicating less muscle edema and less tissue damage (p = 0.05). Heat shock preconditioning 24 hours before an ischemic event leads to an up-regulation of heat shock protein 72 in muscle and to a tissue protection reducing ischemia-reperfusion injury in composite tissue transplantation.     

Effect of rapid and slow cooling on thermoregulatory responses in hypertensive and normotensive rats after calcium administration

The effect of iontophoretic administration of calcium ions to skin in the area of cold stimulus application on the thermal thresholds and the magnitude of cold defense responses in normotensive Wistar and hypertensive ISIAH rats was studied. In thermoneutral conditions, administration of calciumions wos without effect on the measured thermoregulatory parameters. Under the effect of calcium, the thresholds of all the thermoregulatory responses to cooling (such as heat loss, oxygen consumption, shivering) are lowered and the values of heat loss and shivering thermogenesis are considerably increased. The effects of calcium on thermoregulatory responses depend on the rate of cooling. All changes are more expressive in hypertensive rats. The increased sensitivity of hypertensives to calcium suggests that change in their calcium metabolism may be a cause of the observed shifts in the thermoregulatory response to cold.     

Sensory perturbations using suture and sutureless repair of transected median nerve in rats

The effects of changes to cold, mechanical, and heat thresholds following median nerve transection with repair by sutures (Su) or Rose Bengal adhesion (RA) were compared to sham-operated animals. Both nerve-injured groups showed a transient, ipsilateral hyposensitivity to mechanical and heat stimuli followed by a robust and long-lasting hypersensitivity (6–7 weeks) with gradual recovery towards pre-injury levels by 90 days post-repair. Both tactile and thermal hypersensitivity were seen in the contralateral limb that was similar in onset but differed in magnitude and resolved more rapidly compared to the injured limb. Prior to injury, no animals showed any signs of aversion to cold plate temperatures of 4–16?°C. After injury, animals showed cold allodynia, lasting for 7 weeks in RA-repaired rats before recovering towards pre-injury levels, but were still present at 12 weeks in Su-repaired rats. Additionally, sensory recovery in the RA group was faster compared to the Su group in all behavioural tests. Surprisingly, sham-operated rats showed similar bilateral behavioural changes to all sensory stimuli that were comparable in onset and magnitude to the nerve-injured groups but resolved more quickly compared to nerve-injured rats. These results suggest that nerve repair using a sutureless approach produces an accelerated recovery with reduced sensorimotor disturbances compared to direct suturing. They also describe, for the first time, that unilateral forelimb nerve injury produces mirror-image-like sensory perturbations in the contralateral limb, suggesting that the contralateral side is not a true control for sensory testing. The potential mechanisms involved in this altered behaviour are discussed.     

Neuroprotective Effect of Erythropoietin against Pressure Ulcer in a Mouse Model of Small Fiber Neuropathy

An increased risk of skin pressure ulcers (PUs) is common in patients with sensory neuropathies, including those caused by diabetes mellitus. Recombinant human erythropoietin (rhEPO) has been shown to protect the skin against PUs developed in animal models of long-term diabetes. The aim of this work was to determine whether rhEPO could prevent PU formation in a mouse model of drug-inducedSFN. Functional SFN was induced by systemic injection of resiniferatoxin (RTX, 50 µg/kg, i.p.). RhEPO (3000 UI/kg, i.p.) was given the day before RTX injection and then every other day. Seven days after RTX administration, PUs were induced by applying two magnetic plates on the dorsal skin. RTX-treated mice expressed thermal and mechanical hypoalgesia and showed calcitonin gene-related peptide (CGRP) and substance P (SP) depletion without nerve degeneration or vascular dysfunction. RTX mice developed significantly larger stage 2 PUs than Vehicle mice. RhEPO prevented thermal and mechanical hypoalgesia and neuropeptide depletion in small nerve fibers. RhEPO increased hematocrit and altered endothelium-dependent vasodilatation without any effect on PU formation in Vehicle mice. The characteristics of PUs in RTX mice treated with rhEPO and Vehicle mice were found similar. In conclusion, RTX appeared to increased PU development through depletion of CGRP and SP in small nerve fibers, whereas systemic rhEPO treatment had beneficial effect on peptidergic nerve fibers and restored skin protective capacities against ischemic pressure. Our findings support the evaluation of rhEPO and/or its non-hematopoietic analogs in preventing to prevent PUs in patients with SFN.     

The Effect of Local Cooling of Cucumber and Wheat Seedlings on Various Kinds of Stress Resistance of Their Leaves and Roots

Shoots and roots of wheat (Triticum aestivum L., cold-resistant species) and cucumber (Cucumis sativus L., cold-sensitive species) were chilled at 2°C or 10°C, respectively, for 7 h. The changes in cold, heat, and salt resistance in treated leaf and root cells were recorded. Local cooling of the leaf resulted in an increase of its cold and salt tolerance, but its heat tolerance remained unchanged. At the same time, cold tolerance of the root slightly increased as a result of local cooling, but its heat and salt tolerance decreased. Cooling of the shoot did not affect the cold and heat tolerance of root cells but caused a decrease in their salt tolerance. Finally, in the leaf maintained at a normal temperature, there was an increase in all kinds of stress resistance as a result of root cooling. We discuss the possibility of an unspecific change in stress resistance caused by metabolic shifts. These shifts are induced by a signal, which is transmitted inside the plant into plant organs located at a considerable distance from the chilled ones.     

Nicorandil inhibits TLR4/MyD88/NF-κB/NLRP3 signaling pathway to reduce pyroptosis in rats with myocardial infarction

Pyroptosis is an inflammatory cell death that regulates cardiomyocyte loss after myocardial infarction. Reports indicate that nicorandil has a strong anti-inflammatory effect and protects the myocardium from myocardial infarction. However, its relationship with pyroptosis is largely unreported. Here, we investigated to influence and mechanism of action of nicorandil on cardiomyocyte pyroptosis. Forty Sprague Dawley rats were randomly assigned to sham, MI, MI + nicorandil, and MI + nicorandil + TAK242 groups (10 per group). Myocardial infarction modeling was performed through ligation of the anterior descending branch of the left coronary artery. The function of cardiac was evaluated through echocardiography, detection of myocardial adenine nucleotides, cTnI, LDH, TTC, and HE staining. Moreover, we used qRT-PCR, immunohistochemistry, and Western blotting to examine the expression of pyroptosis-related molecules and the inflammasome pathway of TLR4/MyD88/NF-κB/NLRP3. Myocardial infarction caused the activation of GSDMD, aggravated myocardial injury, and triggered cardiac dysfunction. Myocardial infarction induced pyroptotic cell death, manifested as upregulation in mRNA and protein levels associated with pyroptosis, including caspase-1 cleavage and increased expression of IL-1β and IL-18. These changes were mitigated by nicorandil. The achieved data implicate that myocardial infarction induces pyroptosis via the TLR4/MyD88/NF-κB/NLRP3 pathway, which can be inhibited by nicorandil pretreatment. Therefore, nicorandil exerts cardioprotective effects by activating K_ATP channels, and at least in part through inhibition of the TLR4/MyD88/NF-κB/NLRP3 pathway to reduce myocardial infarction-induced pyroptosis. As such, it is a potential therapy for ischemic heart disease.     

Apoptin induces pyroptosis of colorectal cancer cells via the GSDME-dependent pathway

Apoptin is a small molecular weight protein encoded by the VP3 gene of chicken anemia virus (CAV). It can induce apoptosis of tumor cells and play anti-tumorigenic functions. In this study, we identified a time-dependent inhibitory role of apoptin on the viability of HCT116 cells. We also demonstrated that apoptin induces pyroptosis through cleaved caspase 3, and with a concomitant cleavage of gasdermin E (GSDME) rather than GSDMD. GSDME knockdown switched the apoptin-induced cell death from pyroptosis to apoptosis in vitro. Furthermore, we demonstrated that the effect of apoptin on GSDME-dependent pyroptosis could be mitigated by caspase-3 and caspase-9 siRNA knockdown. Additionally, apoptin enhanced the intracellular reactive oxygen species (ROS), causing aggregation of the mitochondrial membrane protein Tom20. Moreover, bax and cytochrome c were released to the activating caspase-9, eventually triggering pyroptosis. Therefore, GSDME mediates the apoptin-induced pyroptosis through the mitochondrial apoptotic pathway. Finally, using nude mice xenografted with HCT116 cells, we found that apoptin induces pyroptosis and significantly inhibits tumor growth. Based on this mechanism, apoptin may provide a new strategy for colorectal cancer therapy.     

Synthetic heat at mild temperatures

"Synthetic heat", also known as the heat grill illusion, occurs when contact with spatially adjacent warm and cold stimuli produce a sensation of "heat". This phenomenon has been explained as a painful perception that occurs when warm stimulation inhibits cold-sensitive neurons in the spinothalamic tract (STT), which in turn unmasks activity in the pain pathway caused by stimulation of C-polymodal nociceptors (CPNs). The "unmasking model" was tested in experiment 1 by combining warm (35-40 degrees C) and cool (> or = 27 degrees C) stimuli that were too mild to stimulate CPNs. After discovering that these temperatures produced nonpainful heat, experiment 2 was designed to determine whether heat could be induced when near-threshold cooling was paired with mild warmth, and whether lowering the base temperature for cooling would increase the noxious (burning, stinging) components of heat for fixed cooling steps of 1-3 degrees C. Cooling by just 1 degrees C from a base temperature of 33 degrees C led to reports of heat on more than 1/3 of trials, and cooling by just 3 degrees C evoked heat on 75% of trials. Lowering the base temperature to 31 or 29 degrees C increased reports of heat and burning but did not produce significant reports of pain. Perception of nonpainful heat at such mild temperatures indicates either that cold-sensitive nociceptors with thresholds very similar to cold fibers innervate hairy skin in humans, or that heat can result from integration of warm fiber and cold fiber activity, perhaps via convergence on nonspecific (e.g., WDR) neurons in the STT.     

The role of microglia mediated pyroptosis in neonatal hypoxic-ischemic brain damage

Neonatal hypoxic-ischemic encephalopathy (HIE) often leads to neonatal death or severe, irreversible neurological deficits. Pathologically, the occurrence of massive cell death and subsequent inflammation suggested that pyroptosis, an inflammation associated programed cell death, might play a role in HIE. Here, by measuring changes of key molecules in pyroptosis pathway in HIE patients, we discovered that their elevation levels tightly correlate with the severity of HIE. Next, we demonstrated that application of MCC950, a small molecule to inhibit NLRP3 inflammasome and thus pyroptosis, substantially alleviated pyroptosis and the injury severity in rats with neonatal hypoxic-ischemic brain damage (HIBD). Mechanistically, we showed that NLRP-3/caspase-1/GSDMD axis is required for microglia pyroptosis and activation. Our data demonstrated that microglia mediated pyroptosis played a crucial role in neonatal HIE, which shed lights into the development of intervention avenues targeting pyroptosis to treat HIE and traumatic brain injuries.