In contrast to molecular changes associated with increased inflammatory responses, little is known about intracellular counter-regulatory mechanisms that control signaling cascades associated with functional responses of neutrophils. Active RHO GTPases are typically considered as effector proteins that elicit cellular responses. Strikingly, we show here that RHOH, although being constitutively GTP-bound, limits neutrophil degranulation and the formation of neutrophil extracellular traps (NETs). Mechanistically, RHOH is induced under inflammatory conditions and binds to non-muscle myosin heavy chain IIA (NMHC IIA) in activated neutrophils in order to inhibit the transport of mitochondria and granules along actin filaments, which is partially reverted upon disruption of the interaction with NMHC IIA by introducing a mutation in RhoH at lysine 34 (RhoHK34A). In parallel, RHOH inhibits actin polymerization presumably by modulating RAC1 activity. In vivo studies using Rhoh-/- mice, demonstrate an increased antibacterial defense capability against Escherichia coli (E. coli). Collectively, our data reveal a previously undefined role of RHOH as a molecular brake for actomyosin-mediated neutrophil effector functions, which represents an intracellular regulatory axis involved in controlling the strength of an antibacterial inflammatory response.

Neutrophils are the most numerous cells in the leukocyte population and essential for innate immunity. To limit their effector functions, neutrophils are able to modulate glycolysis and other cellular metabolic pathways. These metabolic pathways are essential not only for energy usage, but also for specialized effector actions, such as the production of reactive oxygen species (ROS), chemotaxis, phagocytosis, degranulation, and the formation of neutrophil extracellular traps (NETs). It has been demonstrated that activated viable neutrophils can produce NETs, which consists of a DNA scaffold able to bind granule proteins and microorganisms. The formation of NETs requires the availability of increased amounts of adenosine triphosphate (ATP) as it is an active cellular and therefore energy-dependent process. In this article, we discuss the glycolytic and other metabolic routes in association with neutrophil functions focusing on their role for building up NETs in the extracellular space. A better understanding of the requirements of metabolic pathways for neutrophil functions may lead to the discovery of molecular targets suitable to develop novel anti-infectious and/or anti-inflammatory drugs.

Protein tyrosine kinases regulate osteoarthritis (OA) progression by activating a series of signal transduction pathways. However, the roles of protein tyrosine phosphatases (PTPs) in OA remain obscure. This study was undertaken to identify specific PTPs involved in OA and investigate their underlying mechanisms.

Neutrophils are the most abundant innate immune cells in human blood, emerging as important players in a variety of diseases. Mitochondria are bioenergetic, biosynthetic, and signaling organelles critical for cell fate and function. Mitochondria have been overlooked in neutrophil research owing to the conventional view that neutrophils contain few, if any, competent mitochondria and do not rely on these organelles for adenosine triphosphate production. A growing body of evidence suggests that mitochondria participate in neutrophil biology at many levels, ranging from neutrophil development to chemotaxis, effector function, and cell death. Moreover, mitochondria and mitochondrial components, such as mitochondrial deoxyribonucleic acid, can be released by neutrophils to eliminate infection and/or shape immune response, depending on the specific context. In this review, we provide an update on the functional role of mitochondria in neutrophils, highlight mitochondria as key players in modulating the neutrophil phenotype and function during infection and inflammation, and discuss the possibilities and challenges to exploit the unique aspects of mitochondria in neutrophils for disease treatment.

The infusion of coronavirus disease 2019 (COVID-19) patients with mesenchymal stem cells (MSCs) potentially improves clinical symptoms, but the underlying mechanism remains unclear. We conducted a randomized, single-blind, placebo-controlled (29 patients/group) phase II clinical trial to validate previous findings and explore the potential mechanisms. Patients treated with umbilical cord-derived MSCs exhibited a shorter hospital stay ( P = 0.0198) and less time required for symptoms remission ( P = 0.0194) than those who received placebo. Based on chest images, both severe and critical patients treated with MSCs showed improvement by day 7 ( P = 0.0099) and day 21 ( P = 0.0084). MSC-treated patients had fewer adverse events. MSC infusion reduced the levels of C-reactive protein, proinflammatory cytokines, and neutrophil extracellular traps (NETs) and promoted the maintenance of SARS-CoV-2-specific antibodies. To explore how MSCs modulate the immune system, we employed single-cell RNA sequencing analysis on peripheral blood. Our analysis identified a novel subpopulation of VNN2 + hematopoietic stem/progenitor-like (HSPC-like) cells expressing CSF3R and PTPRE that were mobilized following MSC infusion. Genes encoding chemotaxis factors — CX3CR1 and L-selectin — were upregulated in various immune cells. MSC treatment also regulated B cell subsets and increased the expression of costimulatory CD28 in T cells in vivo and in vitro. In addition, an in vivo mouse study confirmed that MSCs suppressed NET release and reduced venous thrombosis by upregulating kindlin-3 signaling. Together, our results underscore the role of MSCs in improving COVID-19 patient outcomes via maintenance of immune homeostasis.

目的:探讨ClC-3氯通道在顺铂诱导的鼻咽癌细胞凋亡中的作用及机制.方法:将不同浓度的顺铂作用于人低分化鼻咽癌细胞(CNE-2Z细胞);MTT法检测不同浓度的顺铂处理24h和48h后细胞活力;采用ClC-3-siRNA下调ClC-3的表达,Annexin V-FITC/PI双染法检测细胞凋亡,多功能微孔板检测仪和流式细胞术检测细胞不同状态下的ROS水平.结果:(1)顺铂呈时间和浓度依赖性抑制CNE-2Z细胞生长,氯通道阻断剂DIDS显著抑制顺铂引起的细胞凋亡(P＜0.01);(2)顺铂促进CNE-2Z细胞ClC-3表达,下调ClC-3蛋白表达后,顺铂诱导的细胞凋亡率下降(P＜0.05);(3)顺铂促进CNE-2Z细胞ROS产生,用抗氧化剂抑制细胞产生ROS后,顺铂诱导的ClC-3蛋白表达和凋亡被抑制,而下调ClC-3蛋白表达对ROS水平影响不大.结论:顺铂可通过提升CNE-2Z细胞ROS水平,上调氯通道ClC-3蛋白水平,从而诱导细胞凋亡.

Chronic low-grade inflammation plays an important role in the pathogenesis of type 2 diabetes. Src homology 2 domain-containing tyrosine phosphatase-2 (SHP2) has been reported to play diverse roles in different tissues during the development of metabolic disorders. We previously reported that SHP2 inhibition in macrophages results in increased cytokine production. Here, we investigated the association between SHP2 inhibition in macrophages and the development of metabolic diseases. Unexpectedly, we found that mice with a conditional SHP2 knockout in macrophages (cSHP2-KO) have ameliorated metabolic disorders. cSHP2-KO mice fed a high-fat diet (HFD) gained less body weight and exhibited decreased hepatic steatosis, as well as improved glucose intolerance and insulin sensitivity, compared with HFD-fed WT littermates. Further experiments revealed that SHP2 deficiency leads to hyperactivation of caspase-1 and subsequent elevation of interleukin 18 (IL-18) levels, both in vivo and in vitro Of note, IL-18 neutralization and caspase-1 knockout reversed the amelioration of hepatic steatosis and insulin resistance observed in the cSHP2-KO mice. Administration of two specific SHP2 inhibitors, SHP099 and Phps1, improved HFD-induced hepatic steatosis and insulin resistance. Our findings provide detailed insights into the role of macrophagic SHP2 in metabolic disorders. We conclude that pharmacological inhibition of SHP2 may represent a therapeutic strategy for the management of type 2 diabetes.

Nutrient deficiency develops frequently in nasopharyngeal carcinoma cell (CNE-2Z) due to the characteristics of aggregation and uncontrolled proliferation. Therefore, starvation can induce autophagy in these cells. Chloride channel 3 (ClC-3), a member of the chloride channel family, is involved in various biological processes. However, whether ClC-3 plays an important role in starvation-induced autophagy is unclear. In this study, Earle's balanced salt solution (EBSS) was used to induce autophagy in CNE-2Z cells. We found that autophagy and the chloride current induced by EBSS were inhibited by chloride channel blockers. ClC-3 knockdown inhibited the degradation of LC3-II and P62. Furthermore, when reactive oxygen species (ROS) generation was suppressed by antioxidant N-acetyl-l-cysteine (L-NAC) pretreatment, EBSS-induced autophagy was inhibited, and the chloride current was unable to be activated. Nevertheless, ClC-3 knockdown had little effect on ROS levels, indicating that ROS acted upstream of ClC-3 and that both ROS and ClC-3 participated in EBSS-induced autophagy regulation in CNE-2Z.

Radiation-induced lung injury (RILI) is one of the most common and fatal complications of thoracic radiotherapy, whereas no effective interventions are available. Andrographolide, an active component extracted from Andrographis paniculate, is prescribed as a treatment for upper respiratory tract infection. Here we report the potential radioprotective effect and mechanism of Andrographolide on RILI. C57BL/6 mice were exposed to 18 Gy of whole thorax irradiation, followed by intraperitoneal injection of Andrographolide every other day for 4 weeks. Andrographolide significantly ameliorated radiation-induced lung tissue damage, inflammatory cell infiltration, and pro-inflammatory cytokine release in the early phase and progressive fibrosis in the late phase. Moreover, Andrographolide markedly hampered radiation-induced activation of the AIM2 inflammasome and pyroptosis in vivo. Furthermore, bone marrow-derived macrophages (BMDMs) were exposed to 8 Gy of X-ray radiation in vitro and Andrographolide significantly inhibited AIM2 inflammasome mediated-pyroptosis in BMDMs. Mechanistically, Andrographolide effectively prevented AIM2 from translocating into the nucleus to sense DNA damage induced by radiation or chemotherapeutic agents in BMDMs. Taken together, Andrographolide ameliorates RILI by suppressing AIM2 inflammasome mediated-pyroptosis in macrophage, identifying Andrographolide as a novel potential protective agent for RILI.

肝动脉-门静脉瘘(hepatic arterioportal fistula, HAPF)是指在先天性或后天性瘘因素作用下,肝动脉和门静脉 2 个系统的血流通过瘘口相互交通,其主要临床表现为门脉高压症[1].创伤性和医源性有创检查导致的 HAPF 多为个案报告或散发病例报告[2-5],鲜有对 HAPF 进行系统分析的文献报道.本研究通过高分辨率计算机断层扫描(computed tomography, CT)及血管三维重建技术对 1 例 HAPF 患者进行诊断,以清晰展现瘘口情况并分析 HAPF 发病原因.此外,本研究通过 PubMed 和中国知网(CNKI)进行关键词检索,收集并回顾性分析 1970-2017 年创伤性或医源性 HAPF 病例资料并总结其临床表现.

In contrast to the "Warburg effect" or aerobic glycolysis earlier generalized as a phenomenon in cancer cells, more and more recent evidence indicates that functional mitochondria are pivotal for ensuring the energy supply of cancer cells. Here, we report that cancer cells with reduced autophagy-related protein 12 (ATG12) expression undergo an oncotic cell death, a phenotype distinct from that seen in ATG5-deficient cells described before. In addition, using untargeted metabolomics with ATG12-deficient cancer cells, we observed a global reduction in cellular bioenergetic pathways, such as β-oxidation (FAO), glycolysis, and tricarboxylic acid cycle activity, as well as a decrease in mitochondrial respiration as monitored with Seahorse experiments. Analyzing the biogenesis of mitochondria by quantifying mitochondrial DNA content together with several mitochondrion-localizing proteins indicated a reduction in mitochondrial biogenesis in ATG12-deficient cancer cells, which also showed reduced hexokinase II expression and the upregulation of uncoupling protein 2. ATG12, which we observed in normal cells to be partially localized in mitochondria, is upregulated in multiple types of solid tumors in comparison with normal tissues. Strikingly, mouse xenografts of ATG12-deficient cells grew significantly slower as compared with vector control cells. Collectively, our work has revealed a previously unreported role for ATG12 in regulating mitochondrial biogenesis and cellular energy metabolism and points up an essential role for mitochondria as a failsafe mechanism in the growth and survival of glycolysis-dependent cancer cells. Inducing oncosis by imposing an ATG12 deficiency in solid tumors might represent an anticancer therapy preferable to conventional caspase-dependent apoptosis that often leads to undesirable consequences, such as incomplete cancer cell killing and a silencing of the host immune system.

Aberrant activation of the NLRP3 inflammasome contributes to the onset and progression of various inflammatory diseases, making it a highly desirable drug target. In this study, we screened a series of small compounds with anti-inflammatory activities and identified a novel NLRP3 inflammasome inhibitor, AI-44, a curcumin analogue that selectively inhibited signal 2 but not signal 1 of NLRP3 inflammasome activation. We demonstrated that AI-44 bound to peroxiredoxin 1 (PRDX1) and promoted the interaction of PRDX1 with pro–Caspase-1 (CASP1), which led to the suppression of association of pro-CASP1 and ASC. Consequently, the assembly of the NLRP3 inflammasome was interrupted, and the activation of CASP1 was inhibited. Knockdown of PRDX1 significantly abrogated the inhibitory effect of AI-44 on the NLRP3 inflammasome. Importantly, AI-44 alleviated LPS-induced endotoxemia in mice via suppressing NLRP3 inflammasome activation. Taken together, our work highlighted PRDX1 as a negative regulator of NLRP3 inflammasome activation and suggested AI-44 as a promising candidate compound for the treatment of sepsis or other NLRP3 inflammasome-driven diseases.

Aberrant activation of NLRP3 inflammasome has an important function in the pathogenesis of various inflammatory diseases. Although many components and mediators of inflammasome activation have been identified, how NLRP3 inflammasome is regulated to prevent excessive inflammation is unclear. Here we show NLRP3 inflammasome stimulators trigger Src homology-2 domain containing protein tyrosine phosphatase-2 (SHP2) translocation to the mitochondria, to interact with and dephosphorylate adenine nucleotide translocase 1 (ANT1), a central molecule controlling mitochondrial permeability transition. This mechanism prevents collapse of mitochondrial membrane potential and the subsequent release of mitochondrial DNA and reactive oxygen species, thus preventing hyperactivation of NLRP3 inflammasome. Ablation or inhibition of SHP2 in macrophages causes intensified NLRP3 activation, overproduction of proinflammatory cytokines IL-1β and IL-18, and increased sensitivity to peritonitis. Collectively, our data highlight that, by inhibiting ANT1 and mitochondrial dysfunction, SHP2 orchestrates an intrinsic regulatory loop to limit excessive NLRP3 inflammasome activation.

Triple-negative breast cancer (TNBC) has an aggressive phenotype and a poor prognosis owing to the high propensity for metastatic progression and the absence of specific targeted treatment. Here, we revealed that small-molecule RL71 targeting sarco/endoplasmic reticulum calcium-ATPase 2 (SERCA2) exhibited potent anti-cancer activity on all TNBC cells tested. Apart from apoptosis induction, RL71 triggered excessive autophagic cell death, the main contributor to RL71-induced TNBC cell death. RL71 augmented the release of Ca2+ from the endoplasmic reticulum (ER) into the cytosol by inhibiting SERCA2 activity. The disruption of calcium homeostasis induced ER stress, leading to apoptosis. More importantly, the elevated intracellular calcium signals induced autophagy through the activation of the CaMKK-AMPK-mTOR pathway and mitochondrial damage. In two TNBC xenograft mouse models, RL71 also displayed strong efficacy including the inhibition of tumor growth, the reduction of metastasis, as well as the prolongation of survival time. These findings suggest SERCA2 as a previous unknown target candidate for TNBC treatment and support the idea that autophagy inducers could be useful as new therapeutics in TNBC treatment.

Human spermatozoa encounter an osmotic decrease from 330 to 290 mOsm l-1 when passing through the female reproductive tract. We aimed to evaluate the role of chloride channels in volume regulation and sperm motility from patients with asthenozoospermia. Spermatozoa were purified using Percoll density gradients. Sperm volume was measured as the forward scatter signal using flow cytometry. Sperm motility was analyzed using computer-aided sperm analysis (CASA). When transferred from an isotonic solution (330 mOsm l-1 ) to a hypotonic solution (290 mOsm l-1 ), cell volume was not changed in spermatozoa from normozoospermic men; but increased in those from asthenozoospermic samples. The addition of the chloride channel blockers, 4,4'-diisothiocyanatostilbene-2,2'- isulfonic acid (DIDS) or 5-nitro-2-(3-phenylpropylamino) benzoic acid (NPPB) to the hypotonic solution caused the normal spermatozoa to swell but did not increase the volume of those from the asthenozoospermic semen. DIDS and NPPB decreased sperm motility in both sets of semen samples. The inhibitory effect of NPPB on normal sperm motility was much stronger than on spermatozoa from the asthenozoospermic samples. Both sperm types expressed ClC-3 chloride channels, but the expression levels in the asthenozoospermic samples were much lower, especially in the neck and mid-piece areas. Spermatozoa from men with asthenozoospermia demonstrated lower volume regulating capacity, mobility, and ClC-3 expression levels (especially in the neck) than did normal spermatozoa. Thus, chloride channels play important roles in the regulation of sperm volume and motility and are downregulated in cases of asthenozoospermia.

In this study, we attempted to explore the effect and possible mechanism of Andrographolide on OVA-induced asthma. OVA challenge induced significant airway inflammatory cell recruitment and lung histological alterations, which were ameliorated by Andrographolide. The protein levels of cytokines in bron-choalveolar fluid (BALF) and serum were reduced by Andrographolide administration as well as the mRNA levels in lung tissue. Mechanically, Andrographolide markedly hampered the activation of nuclear factor-κB (NF-κB) and NLRP3 inflammasome both in vivo and vitro thus decreased levels of TNF-α and IL-1β. Finally, we confirmed that ROS scavenging was responsible for Andrographolide's inactivation of NF-κB and NLRP3 inflammasome signaling. Our study here revealed the effect and possible mechanism of Andrographolide on asthma, which may represent a new therapeutic approach for treating this disease.

Acute lung injury (ALI) or acute respiratory distress syndrome (ARDS) is a severe, life-threatening medical condition characterized by widespread inflammation in the lungs, and is a significant source of morbidity and mortality in the patient population. New therapies for the treatment of ALI are desperately needed. In the present study, we examined the effect of andrographolide sulfonate, a water-soluble form of andrographolide (trade name: Xi-Yan-Ping Injection), on lipopolysaccharide (LPS)-induced ALI and inflammation. Andrographolide sulfonate was administered by intraperitoneal injection to mice with LPS-induced ALI. LPS-induced airway inflammatory cell recruitment and lung histological alterations were significantly ameliorated by andrographolide sulfonate. Protein levels of pro-inflammatory cytokines in bronchoalveolar lavage fluid (BALF) and serum were reduced by andrographolide sulfonate administration. mRNA levels of pro-inflammatory cytokines in lung tissue were also suppressed. Moreover, andrographolide sulfonate markedly suppressed the activation of mitogen-activated protein kinase (MAPK) as well as p65 subunit of nuclear factor-κB (NF-κB). In summary, these results suggest that andrographolide sulfonate ameliorated LPS-induced ALI in mice by inhibiting NF-κB and MAPK-mediated inflammatory responses. Our study shows that water-soluble andrographolide sulfonate may represent a new therapeutic approach for treating inflammatory lung disorders.