GDF11 ameliorates severe acute pancreatitis through modulating macrophage M1 and M2 polarization by targeting the TGFβR1/SMAD-2 pathway

GDF11 Regulates M1 and M2 Polarization of BV2 Microglial Cells via p38 MAPK Signaling Pathway

Growth differentiation factor 11 (GDF11), a member of the transforming growth factor β (TGF-β) superfamily, exhibits great neurological and mental diseases modulating potential. However, its specific effects on microglia, which are the primary immune cells of the nervous system, remain unclear. To investigate the mechanism by which GDF11 affects BV2 microglial cells in vitro and to elucidate its regulatory mechanisms, we carried out a systematic examination of how GDF11 affects the various functions of lipopolysaccharide (LPS)-induced BV2 microglial cells and found that endogenous GDF11 could significantly inhibit cell proliferation, apoptosis, and migration. Specifically, GDF11 inhibited the polarization of BV2 cells to the proinflammatory M1 phenotype and promoted their polarization to the anti-inflammatory M2 phenotype, precipitating a reduction in the expression of CD86 and nitric oxide synthase 2 (NOS2), and an increase in the expression of CD206 and arginase-1. Additionally, RNA-seq and Western blotting experiments revealed that GDF11 activated the p38 MAPK (mitogen-activated protein kinase) pathway, mediating its effects on BV2 cells. Taken together, GDF11 could crucially regulate microglial responses and promote an anti-inflammatory microglial phenotype through the p38 MAPK signaling axis, which may have potential therapeutic implications in neuroinflammatory diseases.

Gdf11 regulates left-right asymmetry development through TGF-β signal

During the embryonic developmental stage in vertebrates, internal organs are arranged along the left-right axis. Disruptions in this process can result in congenital diseases or laterality disorders. The molecular mechanisms of left-right asymmetry in vertebrate development remain largely unclear. Due to its straightforward structure, zebrafish has become a favoured model for studying early laterality events. Here, we demonstrate that growth and development factor 11 (Gdf11) is essential for left-right development via TGF-β signalling. Morphological analysis showed that gdf11 morphants and mutants displayed clear heart and liver laterality disorders in a Nodal signal-dependent manner. Additionally, we found that Kupffer's vesicle formation and ciliogenesis were impaired following gdf11 deletion. We also observed that Gdf11 may form a heterodimer with Spaw, which promotes Smad2/3 phosphorylation and activates TGF-β signalling. Subsequently, Gdf11 promotes left-right laterality by stimulating Foxj1a and its target gene expression. In summary, we reveal a critical role of Gdf11 in left-right patterning, providing fundamental insights into the developmental process of left-right asymmetry.

Deciphering the Protective Role of HIF-1α Downregulation on HIBD through the MALAT1/miR-140-5p/TGFBR1/NF-κB Signaling Pathway

Hypoxic-ischemic brain damage (HIBD) in neonates is a substantial cause of mortality and neurodevelopmental impairment, with the exact molecular mechanisms still being elucidated. The involvement of HIF-1α, MALAT1, miR-140-5p, TGFBR1, and the NF-κB signaling pathway in such injury cascades is of increasing research interest due to their pivotal roles in cellular and pathological processes. This study aimed to explore how HIF-1α regulates the MALAT1/miR-140-5p/TGFBR1/NF-κB signaling axis to participate in the molecular mechanisms of HIBD in neonatal rats. Utilizing bioinformatic analyses and a suite of experimental approaches, the study delineated interactions and regulatory relationships among the molecules. Knockdown of HIF-1α was shown to mitigate brain tissue damage in a neonatal HIBD rat model through the MALAT1/miR-140-5p/TGFBR1/NF-κB signaling axis, revealing a protective effect achieved by inhibiting hippocampal neuron apoptosis and potentially guiding the way toward therapeutic interventions in HIBD. This study implicates the HIF-1α mediated regulation of the MALAT1/miR-140-5p/TGFBR1/NF-κB signaling axis in the pathological development of HIBD, offering insights into novel potential interventional strategies.

Ganoderma lucidum Extract Modulates Gene Expression Profiles Associated with Antioxidant Defense, Cytoprotection, and Senescence in Human Dermal Fibroblasts: Investigation of Quantitative Gene Expression by qPCR

Cellular senescence plays a crucial role in skin aging, with senescent dermal fibroblasts contributing to reduced skin elasticity and increased inflammation. This study investigated the potential of Ganoderma lucidum (Reishi) ethanol extract to modulate the senescent phenotype of human dermal fibroblasts. Reishi powder of two different vendors was used. The extract was produced by extracting the Reishi powder for at least three weeks in 40% ethanol at room temperature. Etoposide-induced senescent fibroblasts were treated with Reishi extracts from two commercial sources for 14 days. Gene expression analysis was performed using qPCR to assess senescence makers, antioxidant defense, and extracellular matrix remodeling. Results showed that Reishi extracts significantly upregulated antioxidant and cytoprotective genes, including Heme oxygenase 1 (HO-1), γ-Glutamylcysteine synthetase (γGCS-L), and NAD(P)H dehydrogenase [quinone] 1 (NQO1), compared to untreated controls. Importantly, Reishi treatment suppressed the expression of p16INK4a, a key marker of cellular senescence, while transiently upregulating p21Cip1. The extracts also demonstrated potential senolytic properties, reducing the percentage of senescent cells as measured by senescence-associated β-galactosidase staining. However, Reishi treatment did not mitigate the upregulation of MMP1 and IL-8 in one Reishi treatment group, indicating differences in the preparations of different vendors. These findings suggest that Ganoderma lucidum extract may help alleviate some aspects of cellular senescence in dermal fibroblasts, primarily through enhanced antioxidant defense and cytoprotection, potentially offering a novel approach to combat skin aging.

GDF11 Mitigates Neuropathic Pain via Regulation of Microglial Polarization and Neuroinflammation through TGF-βR1/SMAD2/NF-κB Pathway in Male Mice

Spinal microglial activation and the polarization towards the M1 phenotype are implicated in the pathological process of neuropathic pain. Extensive research has elucidated that growth and differentiation factor 11 (GDF11), a constituent of the transforming growth factor-β (TGF-β) superfamily, exerts inhibitory effects on macrophage activation and mitigates inflammatory responses via the activation of TGF-β receptor type I (TGF-βR1). Nonetheless, the influence of GDF11 on spinal microglial polarization and its role in neuropathic pain remains to be ascertained. In the present investigation, a neuropathic pain model was induced via a spared nerve injury (SNI) procedure on the sciatic nerve in male mice. The impact of GDF11 on microglial polarization and neuropathic pain in SNI-subjected mice was evaluated through pain behavior assessments, WB, IF, qRT-PCR, and ELISA. Our findings revealed a significant downregulation of spinal GDF11 and TGF-βR1 expression levels in microglia of mice subjected to SNI. Furthermore, GDF11 treatment notably reversed the mechanical allodynia and thermal hyperalgesia, inhibited M1 microglial polarization, and attenuated neuroinflammatory processes by modulating the SMAD2/NF-κB in SNI mice. However, the analgesic effects of GDF11 on pain hypersensitivity and its modulatory influence on spinal microglial polarization were abrogated by the application of a specific antagonist of TGF-βR1, or the TGF-βR1 siRNA. In summary, GDF11 effectively ameliorated mechanical allodynia and thermal hyperalgesia, suppressed M1 microglial polarization, and alleviated neuroinflammation via the regulation of the TGF-βR1/SMAD2/NF-κB pathway in mice with SNI. These findings suggest that GDF11 holds promise as a therapeutic modality for the management of neuropathic pain.

The P2X7-Mediated Mitochondrial ROS as an Emerging Core Target of Tuftsin Nanoparticles in Severe Acute Pancreatitis Therapy via Regulating Mitophagy

20% acute pancreatitis (AP) develops into severe AP (SAP), a global health crisis, with an increased mortality rate to 30%-50%. Mitochondrial damage and immune disorders are direct factors, which exacerbate the occurrence and progression of AP. So far, mitochondrial and immunity injury in SAP remains largely elusive, with no established treatment options available. Immunomodulation is a promising approach to treat pancreatitis. Herein, we proved that Tuftsin (TN), a vital endogenous immunomodulator, can inhibit SAP, while it is limited by extremely short biological half-life, low bioavailability, and the inconvenience of administration. Nano platform is the positive choice. Interestingly, we found that the activated P2X7 signaling was closely associated with the enhanced pancreatic inflammation via damaging mitochondrial function in SAP. Herein, we engineered a nanoplatform containing a Se-Se bond responsive for ROS to deliver TN, namely, DSPE-Se-Se-MPEG@TN (DSSM@TN), contributing to increases in TN's half-life and bioavailability. We synthesized TN-loaded ROS-responsive DSPE-Se-Se- MPEG@TN liposomes (DSSM@TN NPs) via a one-step emulsification method, which exhibited good biosecurity, high stability, suitable size, favorable ROS responsiveness and biocompatibility, as well as excellent capability for releasing TN during oxidative stress and inflammation environment. Moreover, the Se-Se bond with ROS-responsive ability was first proved to play a vital role for TN-loaded liposomes to enhance its anti-inflammation and antioxidant abilities via targeting damaged mitochondria during SAP progression. Mechanistically, DSSM@TN targeting damaged pancreas simultaneously inhibits mitochondrial dysfunction and inflammation in vivo and vitro via mitochondrial P2X7 signaling-impaired Nrf2/HO-1 signaling-inhibited PINK1/PARKIN pathway. Consequently, such a ROS-responsive immunotherapy nanomedicine targeted mitochondria holds great potential in facilitating substantial clinical progress in SAP treatment.

Sestrin2 balances mitophagy and apoptosis through the PINK1-Parkin pathway to attenuate severe acute pancreatitis

Mitophagy serves as a mitochondrial quality control mechanism to maintain the homeostasis of mitochondria and the intracellular environment. Studies have shown that there is a close relationship between mitophagy and apoptosis. Sestrin2 (Sesn2) is a highly conserved class of stress-inducible proteins that play important roles in reducing oxidative stress damage, inflammation, and apoptosis. However, the potential mechanism of how Sesn2 regulates mitophagy and apoptosis in severe acute pancreatitis (SAP) remains unclear. In the study, RAW264.7 (macrophage cell Line) cellular inflammation model established by lipopolysaccharide (LPS) treatment as well as LPS and CAE-induced SAP mouse model (wild-type and Sen2 Knockout mouse) were used. Our study showed that LPS stimulation significantly increased the level of Sesn2 in RAW264.7 cells, Sesn2 increased mitochondrial membrane potential, decreased inflammation levels, mitochondrial superoxide levels and apoptosis, and also promoted monocyte macrophages toward the M2 anti-inflammatory phenotype, suggesting a protective effect of Sesn2 on mitochondria. Further, Sesn2 increased mitophagy and decreased apoptosis via modulating the PINK1-Parkin signaling. Meanwhile, knockout of Sesn2 exacerbated pancreatic, mitochondrial damage and inflammation in a mouse model of SAP. In addition, the protective effect of Sesn2 against SAP was shown to be associated with mitophagy conducted by the PINK1-Parkin pathway via inhibiting apoptosis. These findings reveal that Sesn2 in balancing mitochondrial autophagy and apoptosis by modulating the PINK1-Parkin signaling may present a new therapeutic strategy for the treatment of SAP.

GDF11 promotes osteogenic/odontogenic differentiation of dental pulp stem cells to accelerate dentin restoration via modulating SIRT3/FOXO3-mediated mitophagy

BACKGROUND

Growth differentiation factor 11 (GDF11) is considered to be a potential molecular target for treating pulpitis. However, whether GDF11 regulates osteogenic/odontogenic differentiation of dental pulp stem cells (DPSCs) to mediate pulpitis process remains unclear.

METHODS

Lipopolysaccharide (LPS) was used to induce inflammation conditions in DPSCs. The levels of GDF11, sirtuin 3 (SIRT3), forkhead box O-3 (FOXO3), osteogenic/odontogenic differentiation-related markers were measured by quantitative real-time PCR (qRT-PCR) and western blot (WB). Immunofluorescence staining was used to measure mitophagy. Mitophagy-related proteins were analyzed by WB, and the levels of inflammation factors were examined using qRT-PCR, ELISA and immunohistochemistry. Alkaline phosphatase activity and alizarin red S intensity were evaluated to assess osteogenic differentiation. Acute pulp (AP) injury rat model was constructed to study the role of oe-GDF11 in vivo.

RESULTS

GDF11 was downregulated in LPS-induced DPSCs, and LPS suppressed osteogenic/odontogenic differentiation and mitophagy. GDF11 overexpression promoted osteogenic/odontogenic differentiation in DPSCs through the activation of mitophagy. Furthermore, GDF11 upregulated SIRT3 to enhance FOXO3 expression by inhibiting its acetylation. GDF11 ameliorated LPS-induced inflammation and promoted osteogenic/odontogenic differentiation in DPSCs via enhancing SIRT3/FOXO3-mediated mitophagy. Besides, GDF11 overexpression suppressed inflammation and promoted dentin repair in AP rat models.

CONCLUSION

GDF11 promoted SIRT3/FOXO3-mediated mitophagy to accelerate osteogenic/odontogenic differentiation in DPSCs, providing a novel target for pulpitis treatment.

Growth Differentiation Factor 11 Evokes Lung Injury, Inflammation, and Fibrosis in Mice through the Activin A Receptor Type II-Like Kinase, 53kDa-Smad2/3 Signaling Pathway

Growth differentiation factor 11 (GDF11) belongs to the transforming growth factor beta superfamily and participates in various pathophysiological processes. Initially, GDF11 was suggested to act as a rejuvenator by improving age-related phenotypes of the heart, brain, and skeletal muscle in aged mice. Recent studies demonstrate that GDF11 also serves as an adverse risk factor for human frailty and diseases. However, the role of GDF11 in pulmonary fibrosis (PF) remains unclear. This study explored the role and signaling mechanisms of GDF11 in PF. GDF11 expression was markedly up-regulated in fibrotic lung tissues of both humans and mice. Intratracheal administration of commercial recombinant GDF11 caused lung injury, inflammation, and fibrogenesis in mice. Furthermore, adenovirus-mediated secretory expression of mature GDF11 was exacerbated, whereas full-length GDF11 or the GDF11 propeptide (GDF111-298) alleviated bleomycin-induced PF in mice. In in vitro experiments, GDF11 suppressed the growth of alveolar and bronchial epithelial cells (A549 and BEAS-2B) and human pulmonary microvascular endothelial cells, promoted fibroblast activation, and induced epithelial/endothelial-mesenchymal transition. These effects corresponded to the phosphorylation of Smad2/3, and blocking activin A receptor type II-like kinase, 53kDa (ALK5)-Smad2/3 signaling abolished the in vivo and in vitro effects of GDF11. In conclusion, these findings provide evidence that GDF11 acts as a potent injurious, proinflammatory, and profibrotic factor in the lungs via the ALK5-Smad2/3 pathway.

Inhibition of aquaporin-9 ameliorates severe acute pancreatitis and associated lung injury by NLRP3 and Nrf2/HO-1 pathways

Inflammation, apoptosis and oxidative stress play crucial roles in the deterioration of severe acute pancreatitis-associated acute respiratory distress syndrome (SAP-ARDS). Unfortunately, despite a high mortality rate of 45 %[1], there are limited treatment options available for ARDS outside of last resort options such as mechanical ventilation and extracorporeal support strategies[2]. This study investigated the potential therapeutic role and mechanisms of AQP9 inhibitor RG100204 in two animal models of severe acute pancreatitis, inducing acute respiratory distress syndrome: 1) a sodium-taurocholate induced rat model, and 2) and Cerulein and lipopolysaccharide induced mouse model. RG100204 treatment led to a profound reduction in inflammatory cytokine expression in pancreatic, and lung tissue, in both models. In addition, infiltration of CD68 + and CD11b + cells into these tissues were reduced in RG100204 treated SAP animals, and edema and SAP associated tissue damage were improved. Moreover, we demonstrate that RG100204 reduced apoptosis in the lungs of rat SAP animals, and reduces NF-κB signaling, NLRP3, expression, while profoundly increasing the Nrf2-dependent anti oxidative stress response. We conclude that AQP9 inhibition is a promising strategy for the treatment of pancreatitis and its systemic complications, such as ARDS.

From pancreas to lungs: The role of immune cells in severe acute pancreatitis and acute lung injury

BACKGROUND

Severe acute pancreatitis (SAP) is a potentially lethal inflammatory pancreatitis condition that is usually linked to multiple organ failure. When it comes to SAP, the lung is the main organ that is frequently involved. Many SAP patients experience respiratory failure following an acute lung injury (ALI). Clinicians provide insufficient care for compounded ALI since the underlying pathophysiology is unknown. The mortality rate of SAP patients is severely impacted by it.

OBJECTIVE

The study aims to provide insight into immune cells, specifically their roles and modifications during SAP and ALI, through a comprehensive literature review. The emphasis is on immune cells as a therapeutic approach for treating SAP and ALI.

FINDINGS

Immune cells play an important role in the complicated pathophysiology ofSAP and ALI by maintaining the right balance of pro- and anti-inflammatory responses. Immunomodulatory drugs now in the market have low thepeutic efficacy because they selectively target one immune cell while ignoring immune cell interactions. Accurate management of dysregulated immune responses is necessary. A critical initial step is precisely characterizing the activity of the immune cells during SAP and ALI.

CONCLUSION

Given the increasing incidence of SAP, immunotherapy is emerging as a potential treatment option for these patients. Interactions among immune cells improve our understanding of the intricacy of concurrent ALI in SAP patients. Acquiring expertise in these domains will stimulate the development of innovative immunomodulation therapies that will improve the outlook for patients with SAP and ALI.

The Pivotal Role of Macrophages in the Pathogenesis of Pancreatic Diseases

The pancreas is an organ with both exocrine and endocrine functions, comprising a highly organized and complex tissue microenvironment composed of diverse cellular and non-cellular components. The impairment of microenvironmental homeostasis, mediated by the dysregulation of cell-to-cell crosstalk, can lead to pancreatic diseases such as pancreatitis, diabetes, and pancreatic cancer. Macrophages, key immune effector cells, can dynamically modulate their polarization status between pro-inflammatory (M1) and anti-inflammatory (M2) modes, critically influencing the homeostasis of the pancreatic microenvironment and thus playing a pivotal role in the pathogenesis of the pancreatic disease. This review aims to summarize current findings and provide detailed mechanistic insights into how alterations mediated by macrophage polarization contribute to the pathogenesis of pancreatic disorders. By analyzing current research comprehensively, this article endeavors to deepen our mechanistic understanding of regulatory molecules that affect macrophage polarity and the intricate crosstalk that regulates pancreatic function within the microenvironment, thereby facilitating the development of innovative therapeutic strategies that target perturbations in the pancreatic microenvironment.

Mitochondrial (mt)DNA-cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) signaling promotes pyroptosis of macrophages via interferon regulatory factor (IRF)7/IRF3 activation to aggravate lung injury during severe acute pancreatitis

BACKGROUND

Macrophage proinflammatory activation contributes to the pathology of severe acute pancreatitis (SAP) and, simultaneously, macrophage functional changes, and increased pyroptosis/necrosis can further exacerbate the cellular immune suppression during the process of SAP, where cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) plays an important role. However, the function and mechanism of cGAS-STING in SAP-induced lung injury (LI) remains unknown.

METHODS

Lipopolysaccharide (LPS) was combined with caerulein-induced SAP in wild type, cGAS -/- and sting -/- mice. Primary macrophages were extracted via bronchoalveolar lavage and peritoneal lavage. Ana-1 cells were pretreated with LPS and stimulated with nigericin sodium salt to induce pyroptosis in vitro.

RESULTS

SAP triggered NOD-, LRR-, and pyrin domain-containing protein 3 (NLRP3) inflammasome activation-mediated pyroptosis of alveolar and peritoneal macrophages in mouse model. Knockout of cGAS/STING could ameliorate NLRP3 activation and macrophage pyroptosis. In addition, mitochondrial (mt)DNA released from damaged mitochondria further induced macrophage STING activation in a cGAS- and dose-dependent manner. Upregulated STING signal can promote NLRP3 inflammasome-mediated macrophage pyroptosis and increase serum interleukin (IL)-6, IL-1β, and tumor necrosis factor (TNF)-α levels and, thus, exacerbate SAP-associated LI (SAP-ALI). Downstream molecules of STING, IRF7, and IRF3 connect the mtDNA-cGAS-STING axis and the NLRP3-pyroptosis axis.

CONCLUSIONS

Negative regulation of any molecule in the mtDNA-cGAS-STING-IRF7/IRF3 pathway can affect the activation of NLRP3 inflammasomes, thereby reducing macrophage pyroptosis and improving SAP-ALI in mouse model.

Tissue Expression of Growth Differentiation Factor 11 in Patients with Breast Cancer

Protein growth differentiation factor 11 (GDF11) plays crucial roles in cellular processes, including differentiation and development; however, its clinical relevance in breast cancer patients is poorly understood. We enrolled 68 breast cancer patients who underwent surgery at our hospital and assessed the expression of GDF11 in tumorous, ductal carcinoma in situ (DCIS), and non-tumorous tissues using immunohistochemical staining, with interpretation based on histochemical scoring (H-score). Our results indicated higher GDF11 expressions in DCIS and normal tissues compared to tumorous tissues. In addition, the GDF11 H-score was lower in the patients with a tumor size ≥ 2 cm, pathologic T3 + T4 stages, AJCC III-IV stages, Ki67 ≥ 14% status, HER2-negative, and specific molecular tumor subtypes. Notably, the patients with triple-negative breast cancer exhibited a loss of GDF11 expression. Spearman correlation analysis revealed associations between GDF11 expression and various clinicopathological characteristics, including tumor size, stage, Ki67, and molecular subtypes. Furthermore, GDF11 expression was positively correlated with mean corpuscular hemoglobin concentration and negatively correlated with neutrophil count, as well as standard deviation and coefficient of variation of red cell distribution width. These findings suggest that a decreased GDF11 expression may play a role in breast cancer pathogenesis.

Tectoridin alleviates caerulein-induced severe acute pancreatitis by targeting ERK2 to promote macrophage M2 polarization

Severe acute pancreatitis (SAP) is an inflammatory disease of the pancreas with a high mortality rate. Macrophages play a crucial role in the pathogenesis of pancreatitis. Tectoridin (Tec) is a highly active isoflavone with anti-inflammatory pharmacological activity. However, the role of Tec in the SAP process is not known. The purpose of this study was to investigate the therapeutic effect and potential mechanism of Tec on SAP. To establish SAP mice by intraperitoneal injection of caerulein and Lipopolysaccharide (LPS), the role of Tec in the course of SAP was investigated based on histopathology, biochemical indicators of amylase and lipase and inflammatory factors. The relationship between Tec and macrophage polarization was verified by immunofluorescence, real-time quantitative PCR and Western blot analysis. We then further predicted the possible targets and signal pathways of action of Tec by network pharmacology and molecular docking, and validated them by in vivo and in vitro. In this study, we demonstrated that Tec significantly reduced pancreatic injury in SAP mice, and decreased serum levels of amylase and lipase. The immunofluorescence and Western blot analysis showed that Tec promoted macrophage M2 polarization. Network pharmacology and molecular docking predicted that Tec may target ERK2 for the treatment of SAP, and in vivo and in vitro experiments proved that Tec inhibited the ERK MAPK signal pathway. In summary, Tec can target ERK2, promote macrophage M2 polarization and attenuate pancreatic injury, Tec may be a potential drug for the treatment of SAP.

The regulatory effect of growth differentiation factor 11 on different cells

Growth differentiation factor 11 (GDF11) is one of the important factors in the pathophysiological process of animals. It is widely expressed in many tissues and organs of animals, showing its wide biological activity and potential application value. Previous research has demonstrated that GDF11 has a therapeutic effect on various diseases, such as anti-myocardial aging and anti-tumor. This has not only sparked intense interest and enthusiasm among academics but also spurred some for-profit businesses to attempt to develop GDF11 as a medication for regenerative medicine or anti-aging application. Currently, Sotatercept, a GDF11 antibody drug, is in the marketing application stage, and HS-235 and rGDF11 are in the preclinical research stage. Therefore, we believe that figuring out which cells GDF11 acts on and its current problems should be an important issue in the scientific and commercial communities. Only through extensive, comprehensive research and discussion can we better understand the role and potential of GDF11, while avoiding unnecessary risks and misinformation. In this review, we aimed to summarize the role of GDF11 in different cells and its current controversies and challenges, providing an important reference for us to deeply understand the function of GDF11 and formulate more effective treatment strategies in the future.

Long non-coding RNA MM2P suppresses M1-polarized macrophages-mediated excessive inflammation to prevent sodium taurocholate-induced acute pancreatitis by blocking SHP2-mediated STAT3 dephosphorylation

M1 macrophage-mediated excessive inflammatory response plays a key role in the onset and progression of acute pancreatitis (AP), and this study aimed to investigate the role and underlying mechanisms by which the macrophage polarization-related long noncoding RNA (lncRNA) MM2P participated in the regulation of AP progression. By performing quantitative reverse-transcription PCR (qRT-PCR) assay, lncRNA MM2P was found to be downregulated in both sodium taurocholate-induced AP model mice tissues and lipopolysaccharide (LPS)-stimulated RAW264.7 cells, and gain-of-function experiments confirmed that overexpression of lncRNA MM2P counteracted inflammatory responses, reduced macrophage infiltration and facilitated M1-to-M2 transformation of macrophages to ameliorate AP development in vitro and in vivo. Further mechanical experiments revealed that lncRNA MM2P inhibited Src homology 2 containing protein tyrosine phosphatase 2 (SHP2)-mediated signal transducer and activator of transcription 3 (STAT3) dephosphorylation to activate the STAT3 signaling, and silencing of SHP2 suppressed M1 type skewing in LPS-induced RAW264.7 cells. Interestingly, our rescuing experiments verified that lncRNA MM2P-induced suppressing effects on M1-polarization of LPS-treated RAW264.7 cells were abrogated by co-treating cells with STAT3 inhibitor stattic. Collectively, our data for the first time revealed that lncRNA MM2P suppressed M1-polarized macrophages to attenuate the progression of sodium taurocholate-induced AP, and lncRNA MM2P might be an ideal biomarker for AP diagnosis and treatment.

M2 macrophage polarization: a potential target in pain relief

Pain imposes a significant urden on patients, affecting them physically, psychologically, and economically. Despite numerous studies on the pathogenesis of pain, its clinical management remains suboptimal, leading to the under-treatment of many pain patients. Recently, research on the role of macrophages in pain processes has been increasing, offering potential for novel therapeutic approaches. Macrophages, being indispensable immune cells in the innate immune system, exhibit remarkable diversity and plasticity. However, the majority of research has primarily focused on the contributions of M1 macrophages in promoting pain. During the late stage of tissue damage or inflammatory invasion, M1 macrophages typically transition into M2 macrophages. In recent years, growing evidence has highlighted the role of M2 macrophages in pain relief. In this review, we summarize the mechanisms involved in M2 macrophage polarization and discuss their emerging roles in pain relief. Notably, M2 macrophages appear to be key players in multiple endogenous pathways that promote pain relief. We further analyze potential pathways through which M2 macrophages may alleviate pain.

Growth differentiation factor 11: A new hope for the treatment of cardiovascular diseases

Growth differentiation factor 11 (GDF11) is a member of the transforming growth factor-β superfamily that has garnered significant attention due to its anti-cardiac aging properties. Many studies have revealed that GDF11 plays an indispensable role in the onset of cardiovascular diseases (CVDs). Consequently, it has emerged as a potential target and novel therapeutic agent for CVD treatment. However, currently, no literature reviews comprehensively summarize the research on GDF11 in the context of CVDs. Therefore, herein, we comprehensively described GDF11's structure, function, and signaling in various tissues. Furthermore, we focused on the latest findings concerning its involvement in CVD development and its potential for clinical translation as a CVD treatment. We aim to provide a theoretical basis for the prospects and future research directions of the GDF11 application regarding CVDs.

Exosomal miRNAs-mediated macrophage polarization and its potential clinical application

Macrophages are highly heterogeneous and plastic immune cells that play an important role in the fight against pathogenic microorganisms and tumor cells. After different stimuli, macrophages can polarize to the M1 phenotype to show a pro-inflammatory effect and the M2 phenotype to show an anti-inflammatory effect. The balance of macrophage polarization is highly correlated with disease progression, and therapeutic approaches to reprogram macrophages by targeting macrophage polarization are feasible. There are a large number of exosomes in tissue cells, which can transmit information between cells. In particular, microRNAs (miRNAs) in the exosomes can regulate the polarization of macrophages and further affect the progression of various diseases. At the same time, exosomes are also effective "drug" carriers, laying the foundation for the clinical application of exosomes. This review describes some pathways involved in M1/M2 macrophage polarization and the effects of miRNA carried by exosomes from different sources on the polarization of macrophages. Finally, the application prospects and challenges of exosomes/exosomal miRNAs in clinical treatment are also discussed.

GDF11 Improves Ischemia-Reperfusion-Induced Acute Kidney Injury via Regulating Macrophage M1/M2 Polarization

INTRODUCTION

Acute kidney injury (AKI) is a clinical emergency caused by the rapid decline of renal function caused by various etiologies. Growth differentiation factor 11 (GDF11) can promote renal tubular regeneration and improve kidney function in AKI, but the specific mechanism remains unclear. Herein, we investigated the effect and mechanisms of GDF11 in ameliorating AKI induced by ischemia-reperfusion (I/R).

METHODS

An animal model of AKI was established by I/R method, and the changes of serum urea nitrogen and creatinine were measured to evaluate the AKI. Enzyme-linked immunosorbent assay (ELISA) was used to measure cytokines, malondialdehyde, superoxide dismutase, nitric oxide synthase, and arginase 1 levels. Flow cytometry was used to count the M1/M2 macrophages. IHC, WB, and q-PCR experiments were used to evaluate the expression of GDF11.

RESULTS

The changes in serum levels of urea nitrogen and creatinine after I/R suggest that an animal model of AKI induced by I/R was successfully established. AKI caused by I/R significantly changed the M1/M2 macrophage polarization balance, with an increase in M2 being significantly higher than M1 as well as increased oxidative stress. Treatment with GDF11 after I/R significantly increased the differentiation of M2 cells and inhibited the differentiation of M1 macrophages, as well as decreased oxidative stress.

CONCLUSION

GDF11 can promote the repair of AKI caused by I/R by regulating the balance of M1/M2 polarization in macrophages and oxidative stress.

Identification of Key Biomarkers Associated with Immunogenic Cell Death and Their Regulatory Mechanisms in Severe Acute Pancreatitis Based on WGCNA and Machine Learning

Immunogenic cell death (ICD) is a form of programmed cell death with a strong sense of inflammatory detection, whose powerful situational awareness can cause the reactivation of aberrant immunity. However, the role of ICD in the pathogenesis of severe acute pancreatitis (SAP) has yet to be investigated. This study aims to explore the pivotal genes associated with ICD in SAP and how they relate to immune infiltration and short-chain fatty acids (SCFAs), in order to provide a theoretical foundation for further, in-depth mechanistic studies. We downloaded GSE194331 datasets from the Gene Expression Omnibus (GEO). The use of differentially expressed gene (DEG) analysis; weighted gene co-expression network analysis (WGCNA) and least absolute shrinkage and selection operator (LASSO) regression analysis allowed us to identify a total of three ICD-related hub genes (LY96, BCL2, IFNGR1) in SAP. Furthermore, single sample gene set enrichment analysis (ssGSEA) demonstrated that hub genes are closely associated with the infiltration of specific immune cells, the activation of immune pathways and the metabolism of SCFAs (especially butyrate). These findings were validated through the analysis of gene expression patterns in both clinical patients and rat animal models of SAP. In conclusion, the first concept of ICD in the pathogenesis of SAP was proposed in our study. This has important implications for future investigations into the pro-inflammatory immune mechanisms mediated by damage-associated molecular patterns (DAMPs) in the late stages of SAP.

Exosome-transmitted miR-3124-5p promotes cholangiocarcinoma development via targeting GDF11

Objective

Cholangiocarcinoma (CHOL) is a deadly cancer worldwide with limited available therapies. The aim of this study was to investigate key exosomal miRNAs and their functions in CHOL development.

Methods

Serum exosomes were isolated from patients with CHOL and healthy controls, followed by miRNA sequencing for identifying differentially expressed miRNAs (DEMs) and their functions. Then, the expression of key DEMs was experimentally validated in exosomes from clinical CHOL patients and CHOL cells. The effects of overexpression of key DEMs on CHOL cell migration and proliferation were investigated. A key exosomal DEM miR-3124-5p was identified. The effects of overexpression or knockdown of exosomal miR-3124-5p on the proliferation, migration, and angiogenesis of human umbilical vein endothelial cells (HUVECs) were investigated. Moreover, the function of exosomal miR-3124-5p on tumor growth in vivo was explored.

Results

A total of 632 exosomal DEMs were identified between CHOL and control samples. Target genes of DEMs were significantly enriched in pathways, such as the p53 signaling pathway. miR-3124-5p was upregulated in serum exosomes from CHOL patients and exosomes from CHOL cells, and overexpression of miR-3124-5p promoted RBE cell migration and viability. Moreover, overexpression of exosomal miR-3124-5p promoted the proliferation, migration, and angiogenesis of HUVECs, while knockdown of miR-3124-5p had the opposite effect. miR-3124-5p could target growth differentiation factor 11 (GDF11) and downregulate GDF11 expression. Furthermore, exosomal miR-3124-5p promoted tumor growth in vivo.

Conclusions

Our findings revealed that exosome-encapsulated miR-3124-5p promoted the malignant progression of CHOL by targeting GDF11. Exosomal miR-3124-5p and GDF11 could be promising biomarkers or therapeutic targets for CHOL.