Endoplasmic reticulum stress promoted acinar cell necroptosis in acute pancreatitis through cathepsinB-mediated AP-1 activation

SDF-1/CXCR4 axis maintains porcine prospermatogonia undifferentiated state through regulation of transcription suppressor PLZF

Prospermatogonia (ProSGs), the progenitors of spermatogonial stem cells in neonatal testes, undergo critical migration to the testicular microenvironment-a fundamental process for testicular development and subsequent spermatogenic capacity. The SDF-1/CXCR4 chemokine axis serves as an essential molecular guidance mechanism, directing ProSGs toward the basal membrane of seminiferous tubules. Nevertheless, the precise molecular mechanisms governing this axis remain incompletely understood. Utilizing a porcine in vitro model system, this investigation elucidated the molecular mechanisms underlying the SDF-1/CXCR4 axis in ProSGs fate determination. Through integrated molecular and transcriptomic analyses, we investigated the consequences of CXCR4 inhibition on ProSG cellular dynamics. Our findings demonstrated that the SDF-1/CXCR4 axis exerts regulatory control over ProSGs differentiation via the PI3K-AKT-AP-1 signaling cascade. This regulation significantly influences the transcriptional landscape of ProSGs, particularly modulating the expression of PLZF, a crucial suppressor of spermatogonial differentiation, and DMRT1, an essential mediator of germ cell differentiation. These findings elucidate the molecular mechanisms orchestrating ProSGs homing and emphasize the significance of maintaining male reproductive competence. Furthermore, this research could enhance our understanding of ProSGs biology and its relationship to boar fertility, while potentially facilitating the development of innovative reproductive technologies and sustainable livestock management strategies.

Reactive oxygen species and oxidative stress in acute pancreatitis: Pathogenesis and new therapeutic interventions

Acute pancreatitis (AP) is a common acute gastrointestinal disorder affecting approximately 20% of patients with systemic inflammatory responses that may cause pancreatic and peripancreatic fat necrosis. This condition often progresses to multiple organ failure, significantly increasing morbidity and mortality. Oxidative stress, characterized by an imbalance between the body's reactive oxygen species (ROS) and antioxidants, activates the inflammatory signaling pathways. Although the pathogenesis of AP is not fully understood, ROS are increasingly recognized as critical in the disease's progression and development. Modulating the oxidative stress pathway has shown efficacy in mitigating the progression of AP. Despite numerous basic studies examining this pathway, comprehensive reviews of recent research remain sparse. This systematic review offers an in-depth examination of the critical role of oxidative stress in the pathogenesis and progression of AP and evaluates the therapeutic potential of antioxidant interventions in its management.

Autophagy and the pancreas: Healthy and disease states

Macroautophagy/autophagy is an intracellular degradation pathway that has an important effect on both healthy and diseased pancreases. It protects the structure and function of the pancreas by maintaining organelle homeostasis and removing damaged organelles. A variety of pancreas-related diseases, such as diabetes, pancreatitis, and pancreatic cancer, are closely associated with autophagy. Genetic studies that address autophagy confirm this view. Loss of autophagy homeostasis (lack or overactivation) can lead to a series of adverse reactions, such as oxidative accumulation, increased inflammation, and cell death. There is growing evidence that stimulating or inhibiting autophagy is a potential therapeutic strategy for various pancreatic diseases. In this review, we discuss the multiple roles of autophagy in physiological and pathological conditions of the pancreas, including its role as a protective or pathogenic factor.

The role of hydrogen sulfide in the regulation of necroptosis across various pathological processes

Necroptosis is a programmed cell death form executed by receptor-interacting protein kinase (RIPK) 1, RIPK3 and mixed lineage kinase domain-like protein (MLKL), which assemble into an oligomer called necrosome. Accumulating evidence reveals that necroptosis participates in many types of pathological processes. Hence, clarifying the mechanism of necroptosis in pathological processes is particularly important for the prevention and treatment of various diseases. For over 300 years, hydrogen sulfide (H2S) has been widely known in the scientific community as a toxic and foul-smelling gas. However, after discovering the important physiological and pathological functions of H2S, human understanding of this small molecule changed, believing that H2S is the third gas signaling molecule after carbon monoxide (CO) and nitric oxide (NO). H2S plays an important role in various diseases, but the related mechanisms are not yet fully understood. In recent years, more and more studies have shown that H2S regulation of necroptosis is involved in various pathological processes. Herein, we focus on the recent progress on the role of H2S regulation of necroptosis in different pathological processes and profoundly analyze the related mechanisms.

High-mobility group box 1 fragment ameliorates chronic pancreatitis induced by caerulein in mice

BACKGROUND

Chronic pancreatitis (CP) is a progressive disease characterized by pancreatic fibrosis for which effective treatment options are lacking. Mesenchymal stem cells (MSCs) have shown potential for fibrosis treatment but face limitations in clinical application. The high-mobility group box 1 (HMGB1) fragment mobilizes MSCs from bone marrow into the blood and has emerged as a promising therapeutic agent for tissue regeneration in various pathological conditions. The aim of this study was to investigate the potential therapeutic effects of systemic administration of the HMGB1 fragment in a mouse model of CP.

METHODS

A caerulein-induced CP mouse model was used, and the HMGB1 fragment was administered by tail vein injection. Parameters such as body weight, pancreatic tissue damage, fibrosis, inflammatory cytokine expression, and collagen-related gene expression were evaluated using various assays, including immunohistochemistry, real-time PCR, serum analysis, and single-cell transcriptome analysis. And the migration of MSCs to the pancreas was evaluated using the parabiosis model.

RESULTS

Administration of the HMGB1 fragment was associated with significant improvements in pancreatic tissue damage and fibrosis. It suppressed the expression of inflammatory cytokines and activated platelet-derived growth factor receptor-α+ MSCs, leading to their accumulation in the pancreas. The HMGB1 fragment also shifted gene expression patterns associated with pancreatic fibrosis toward those of the normal pancreas. Systemic administration of the HMGB1 fragment demonstrated therapeutic efficacy in attenuating pancreatic tissue damage and fibrosis in a CP mouse model.

CONCLUSION

These findings highlight the potential of the HMGB1 fragment as a therapeutic target for the treatment of CP.

Oxidative stress and acute pancreatitis (Review)

Acute pancreatitis (AP) is a common inflammatory disorder of the exocrine pancreas that causes severe morbidity and mortality. Although the pathophysiology of AP is poorly understood, a substantial body of evidence suggests some critical events for this disease, such as dysregulation of digestive enzyme production, cytoplasmic vacuolization, acinar cell death, edema formation, and inflammatory cell infiltration into the pancreas. Oxidative stress plays a role in the acute inflammatory response. The present review clarified the role of oxidative stress in the occurrence and development of AP by introducing oxidative stress to disrupt cellular Ca2+ balance and stimulating transcription factor activation and excessive release of inflammatory mediators for the application of antioxidant adjuvant therapy in the treatment of AP.

The role of mitochondrial damage-associated molecular patterns in acute pancreatitis

Acute pancreatitis (AP) is one of the most common gastrointestinal tract diseases with significant morbidity and mortality. Current treatments remain unspecific and supportive due to the severity and clinical course of AP, which can fluctuate rapidly and unpredictably. Mitochondria, cellular power plant to produce energy, are involved in a variety of physiological or pathological activities in human body. There is a growing evidence indicating that mitochondria damage-associated molecular patterns (mtDAMPs) play an important role in pathogenesis and progression of AP. With the pro-inflammatory properties, released mtDAMPs may damage pancreatic cells by binding with receptors, activating downstream molecules and releasing inflammatory factors. This review focuses on the possible interaction between AP and mtDAMPs, which include cytochrome c (Cyt c), mitochondrial transcription factor A (TFAM), mitochondrial DNA (mtDNA), cardiolipin (CL), adenosine triphosphate (ATP) and succinate, with focus on experimental research and potential therapeutic targets in clinical practice. Preventing or diminishing the release of mtDAMPs or targeting the mtDAMPs receptors might have a role in AP progression.

Qing Xia Jie Yi Formula granules alleviated acute pancreatitis through inhibition of M1 macrophage polarization by suppressing glycolysis

ETHNOPHARMACOLOGICAL RELEVANCE

Herbal formulas from Traditional Chinese Medicine are common and well-established practice for treating acute pancreatitis (AP) patients. However, little is known about their bioactive ingredients and mechanisms, such as their targets and pathways to inhibit inflammation.

AIM OF THE STUDY

This study aimed to evaluate the effect of Qing Xia Jie Yi Formula (QXJYF) granules on AP and discuss the molecular mechanisms involved.

MATERIALS AND METHODS

Major compounds in QXJYF granules were identified using UPLC-quadrupole-Orbitrap mass spectrometry (UPLC-Q-Orbitrap MS). The effect of QXJYF granules on experimental AP models both in vitro and in vivo, and detailed mechanisms were clarified. Two AP models were induced in mice by intraperitoneally injections of caerulein or L-arginine, and QXJYF granules were used to treat AP mice in vivo. Histological evaluation of pancreas and lung, serum amylase and lipase levels, serum inflammatory cytokines, inflammatory cell infiltration and macrophage phenotype were assessed. Bone marrow derived macrophages (BMDMs) were cultured and treated with QXJYF granules in vitro. BMDM phenotype and glycolysis levels were measured. Lastly, clinical effect of QXJYF granules on AP patients was verified. Predicted severe AP (pSAP) patients eligible for inclusion were assessed for enrollment.

RESULTS

Nine major compounds were identified in QXJYF granules. Data showed that QXJYF granules significantly alleviated AP severity both in caerulein and L-arginine-induced AP models in vivo, pancreatic injury and inflammatory cell infiltration, systematic inflammation, lung injury and inflammatory cell infiltration were all improved after QXJYF treatment. QXJYF granules significantly reduced M1 macrophages during AP both in vivo and in vitro; besides, the mRNA expression levels of M1 genes such as inos, Tnfα, Il1β and Il6 were significantly lower after QXJYF treatment in M1 macrophages. Mechanistically, we found that HK2, PFKFB3, PKM, LDHα levels were increased in M1 macrophages, but significantly decreased after QXJYF treatment. Clinical data indicated that QXJYF granules could significantly reduce CRP levels and shorten the duration of organ failure, thereby reducing the incidence of SAP and preventing pSAP patients from progressing to SAP.

CONCLUSION

QXJYF granules alleviated AP through the inhibition of M1 macrophage polarization by suppressing glycolysis.

Liproxstatin-1 attenuates acute hypertriglyceridemic pancreatitis through inhibiting ferroptosis in rats

Ferroptosis is closely associated with inflammatory diseases, including acute pancreatitis (AP); however, the involvement of ferroptosis in hypertriglyceridemic pancreatitis (HTGP) remains unclear. In the present study, we aimed to explore the relationship between lipid metabolism and ferroptosis in HTGP and the alleviating effect of liproxstatin-1 (Lip-1) in vivo. This study represents the first exploration of lipid metabolism and endoplasmic reticulum stress (ERS) in HTGP, targeting ferroptosis as a key factor in HTGP. Hypertriglyceridemia (HTG) was induced under high-fat diet conditions. Cerulein was then injected to establish AP and HTGP models. Lip-1, a specific ferroptosis inhibitor, was administered before the induction of AP and HTGP in rats, respectively. Serum triglyceride, amylase, inflammatory factors, pathological and ultrastructural structures, lipid peroxidation, and iron overload indicators related to ferroptosis were tested. Moreover, the interaction between ferroptosis and ERS was assessed. We found HTG can exacerbate the development of AP, with an increased inflammatory response and intensified ferroptosis process. Lip-1 treatment can attenuate pancreatic injury by inhibiting ferroptosis through lipid metabolism and further resisting activations of ERS-related proteins. Totally, our results proved lipid metabolism can promote ferroptosis in HTGP by regulating ACSL4/LPCAT3 protein levels. Additionally, ERS may participate in ferroptosis via the Bip/p-EIF2α/CHOP pathway, followed by the alleviating effect of Lip-1 in the rat model.

The Pathogenesis of Pancreatitis and the Role of Autophagy

The pathogenesis of acute and chronic pancreatitis has recently evolved as new findings demonstrate a complex mechanism operating through various pathways. In this review, the current evidence indicating that several mechanisms act in concert to induce and perpetuate pancreatitis were presented. As autophagy is now considered a fundamental mechanism in the pathophysiology of both acute and chronic pancreatitis, the fundamentals of the autophagy pathway were discussed to allow for a better understanding of the pathophysiological mechanisms of pancreatitis. The various aspects of pathogenesis, including trypsinogen activation, ER stress and mitochondrial dysfunction, the implications of inflammation, and macrophage involvement in innate immunity, as well as the significance of pancreatic stellate cells in the development of fibrosis, were also analyzed. Recent findings on exosomes and the miRNA regulatory role were also presented. Finally, the role of autophagy in the protection and aggravation of pancreatitis and possible therapeutic implications were reviewed.

Ceramide-1-phosphate is a regulator of Golgi structure and is co-opted by the obligate intracellular bacterial pathogen Anaplasma phagocytophilum

Many intracellular pathogens structurally disrupt the Golgi apparatus as an evolutionarily conserved promicrobial strategy. Yet, the host factors and signaling processes involved are often poorly understood, particularly for Anaplasma phagocytophilum, the agent of human granulocytic anaplasmosis. We found that A. phagocytophilum elevated cellular levels of the bioactive sphingolipid, ceramide-1-phosphate (C1P), to promote Golgi fragmentation that enables bacterial proliferation, conversion from its non-infectious to infectious form, and productive infection. A. phagocytophilum poorly infected mice deficient in ceramide kinase, the Golgi-localized enzyme responsible for C1P biosynthesis. C1P regulated Golgi morphology via activation of a PKCα/Cdc42/JNK signaling axis that culminates in phosphorylation of Golgi structural proteins, GRASP55 and GRASP65. siRNA-mediated depletion of Cdc42 blocked A. phagocytophilum from altering Golgi morphology, which impaired anterograde trafficking of trans-Golgi vesicles into and maturation of the pathogen-occupied vacuole. Cells overexpressing phosphorylation-resistant versions of GRASP55 and GRASP65 presented with suppressed C1P- and A. phagocytophilum-induced Golgi fragmentation and poorly supported infection by the bacterium. By studying A. phagocytophilum, we identify C1P as a regulator of Golgi structure and a host factor that is relevant to disease progression associated with Golgi fragmentation.IMPORTANCECeramide-1-phosphate (C1P), a bioactive sphingolipid that regulates diverse processes vital to mammalian physiology, is linked to disease states such as cancer, inflammation, and wound healing. By studying the obligate intracellular bacterium Anaplasma phagocytophilum, we discovered that C1P is a major regulator of Golgi morphology. A. phagocytophilum elevated C1P levels to induce signaling events that promote Golgi fragmentation and increase vesicular traffic into the pathogen-occupied vacuole that the bacterium parasitizes. As several intracellular microbial pathogens destabilize the Golgi to drive their infection cycles and changes in Golgi morphology is also linked to cancer and neurodegenerative disorder progression, this study identifies C1P as a potential broad-spectrum therapeutic target for infectious and non-infectious diseases.

Paired single-B-cell transcriptomics and receptor sequencing reveal activation states and clonal signatures that characterize B cells in acute myeloid leukemia

BACKGROUND

Acute myeloid leukemia (AML) is associated with a dismal prognosis. Immune checkpoint blockade (ICB) to induce antitumor activity in AML patients has yielded mixed results. Despite the pivotal role of B cells in antitumor immunity, a comprehensive assessment of B lymphocytes within AML's immunological microenvironment along with their interaction with ICB remains rather constrained.

METHODS

We performed an extensive analysis that involved paired single-cell RNA and B-cell receptor (BCR) sequencing on 52 bone marrow aspirate samples. These samples included 6 from healthy bone marrow donors (normal), 24 from newly diagnosed AML patients (NewlyDx), and 22 from 8 relapsed or refractory AML patients (RelRef), who underwent assessment both before and after azacitidine/nivolumab treatment.

RESULTS

We delineated nine distinct subtypes of B cell lineage in the bone marrow. AML patients exhibited reduced nascent B cell subgroups but increased differentiated B cells compared with healthy controls. The limited diversity of BCR profiles and extensive somatic hypermutation indicated antigen-driven affinity maturation within the tumor microenvironment of RelRef patients. We established a strong connection between the activation or stress status of naïve and memory B cells, as indicated by AP-1 activity, and their differentiation state. Remarkably, atypical memory B cells functioned as specialized antigen-presenting cells closely interacting with AML malignant cells, correlating with AML stemness and worse clinical outcomes. In the AML microenvironment, plasma cells demonstrated advanced differentiation and heightened activity. Notably, the clinical response to ICB was associated with B cell clonal expansion and plasma cell function.

CONCLUSIONS

Our findings establish a comprehensive framework for profiling the phenotypic diversity of the B cell lineage in AML patients, while also assessing the implications of immunotherapy. This will serve as a valuable guide for future inquiries into AML treatment strategies.

The role of TRPV4 in programmed cell deaths

Programmed cell death is a major life activity of both normal development and disease. Necroptosis is early recognized as a caspase-independent form of programmed cell death followed obviously inflammation. Apoptosis is a gradually recognized mode of cell death that is characterized by a special morphological changes and unique caspase-dependent biological process. Ferroptosis, pyroptosis and autophagy are recently identified non-apoptotic regulated cell death that each has its own characteristics. The transient receptor potential vanilloid 4 (TRPV4) is a kind of nonselective calcium-permeable cation channel, which is received more and more attention in biology studies. It is widely expressed in human tissues and mainly located on the membrane of cells. Several researchers have identified that the influx Ca2+ from TRPV4 acts as a key role in the loss of cells by apoptosis, ferroptosis, necroptosis, pyroptosis and autophagy via mediating endoplasmic reticulum (ER) stress, oxidative stress and inflammation. This effect is bad for the normal function of organs on the one hand, on the other hand, it is benefit for anticancer activities. In this review, we will summarize the current discovery on the role and impact of TRPV4 in these programmed cell death pathological mechanisms to provide a new prospect of gene therapeutic target of related diseases.

The role of proteomics in acute pancreatitis: new and old knowledge

INTRODUCTION

Around 20% of individuals diagnosed with acute pancreatitis (AP) may develop severe acute pancreatitis (SAP), possibly resulting in a mortality rate ranging from 15% to 35%. There is an urgent need to thoroughly understand the molecular phenotypes of SAP resulting from diverse etiologies. The field of translational research on AP has seen the use of several innovative proteomic methodologies via the ongoing improvement of isolation, tagging, and quantification methods.

AREAS COVERED

This paper provides a comprehensive overview of differentially abundant proteins (DAPs) identified in AP by searching the PubMed/MEDLINE database (2003-2023) and adds significantly to the current theoretical framework.

EXPERT OPINION

DAPs for potentially diagnosing AP based on proteomic identification need to be confirmed by multi-center studies that include larger samples. The discovery of DAPs in various organs at different AP stages via proteomic technologies is essential better to understand the pathophysiology of AP-related multiple organ dysfunction syndrome. Regarding the translational research of AP, novel approaches like single-cell proteomics and imaging using mass spectrometry may be used as soon as they become available.

Alendronate augments lipid A‑induced IL‑1β release by ASC‑deficient RAW264 cells via AP‑1 activation

Alendronate (ALN) is an anti-bone-resorptive drug with inflammatory side effects. ALN upregulates lipid A-induced interleukin (IL)-1α and IL-1β release by J774.1 cells via apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC) activation. The present study examined whether ALN augmented lipid A-induced proinflammatory cytokine production using ASC-deficient mouse macrophage-like RAW264 cells. Pretreatment of RAW264 cells with ALN significantly augmented lipid A-induced IL-1β release, although ALN did not upregulate the expression of Toll-like receptor 4, myeloid differentiation factor 88 (MyD88) and caspase-11. Moreover, pretreatment of caspase-11-deficient RAW264.7 cells with ALN significantly augmented lipid A-induced IL-1β release. Notably, ALN upregulated the activation of FosB, c-Jun or JunD, but not c-Fos or NF-κB in RAW264 cells. Furthermore, pretreatment with the activator protein 1 (AP-1) inhibitor SR11302, but not the c-Fos inhibitor T-5224, before addition of ALN inhibited ALN-augmented IL-1β release by lipid A-treated RAW264 cells. SR11302 also reduced ALN-augmented lactate dehydrogenase release by the cells. These findings collectively suggested that ALN augmented lipid A-induced IL-1β release and cell membrane damage in ASC-deficient RAW264 cells via activation of AP-1, but not NF-κB.

Celastrol inhibits necroptosis by attenuating the RIPK1/RIPK3/MLKL pathway and confers protection against acute pancreatitis in mice

Necroptosis is a necrotic form of regulated cell death, which is primarily mediated by the receptor-interacting protein kinase 1 (RIPK1), RIPK3, and mixed lineage kinase domain-like (MLKL) pathway in a caspase-independent manner. Necroptosis has been found to occur in virtually all tissues and diseases evaluated, including pancreatitis. Celastrol, a pentacyclic triterpene extracted from the roots of Tripterygium wilfordii (thunder god vine), possesses potent anti-inflammatory and anti-oxidative activities. Yet, it is unclear whether celastrol has any effects on necroptosis and necroptotic-related diseases. Here we showed that celastrol significantly suppressed necroptosis induced by lipopolysaccharide (LPS) plus pan-caspase inhibitor (IDN-6556) or by tumor-necrosis factor-α in combination with LCL-161 (Smac mimetic) and IDN-6556 (TSI). In these in vitro cellular models, celastrol inhibited the phosphorylation of RIPK1, RIPK3, and MLKL and the formation of necrosome during necroptotic induction, suggesting its possible action on upstream signaling of the necroptotic pathway. Consistent with the known role of mitochondrial dysfunction in necroptosis, we found that celastrol significantly rescued TSI-induced loss of mitochondrial membrane potential. TSI-induced intracellular and mitochondrial reactive oxygen species (mtROS), which are involved in the autophosphorylation of RIPK1 and recruitment of RIPK3, were significantly attenuated by celastrol. Moreover, in a mouse model of acute pancreatitis that is associated with necroptosis, celastrol administration significantly reduced the severity of caerulein-induced acute pancreatitis accompanied by decreased phosphorylation of MLKL in pancreatic tissues. Collectively, celastrol can attenuate the activation of RIPK1/RIPK3/MLKL signaling likely by attenuating mtROS production, thereby inhibiting necroptosis and conferring protection against caerulein-induced pancreatitis in mice.