Helicobacter pylori infection induces STAT3 phosphorylation on Ser727 and autophagy in human gastric epithelial cells and mouse stomach

Gut-brain axis interplay via STAT3 pathway: Implications of Helicobacter pylori derived secretome on inflammation and Alzheimer's disease

Helicobacter pylori is a pathogenic bacterium that causes gastritis and gastric carcinoma. Besides gastric complications its potential link with gut-brain axis disruption and neurological disorders has also been reported. The current study investigated the plausible role and its associated molecular mechanism underlying H. pylori mediated gut-brain axis disruption and neuroinflammation leading to neurological modalities like Alzheimer's disease (AD). We have chosen the antimicrobial resistant and susceptible H. pylori strains on the basis of broth dilution method. We have observed the increased inflammatory response exerted by H. pylori strains in the gastric as well as in the neuronal compartment after treatment with Helicobacter pylori derived condition media (HPCM). Further, elevated expression of STAT1, STAT3, and AD-associated proteins- APP and APOE4 was monitored in HPCM-treated neuronal and neuron-astrocyte co-cultured cells. Excessive ROS generation has been found in these cells. The HPCM treatment to LN229 causes astrogliosis, evidenced by increased glial fibrillary acidic protein. Our results indicate the association of STAT3 as an important regulator in the H. pylori-mediated pathogenesis in neuronal cells. Notably, the inhibition of STAT3 by its specific inhibitor, BP-1-102, reduced the expression of pSTAT3 and AD markers in neuronal compartment induced by HPCM. Thus, our study demonstrates that H. pylori infection exacerbates inflammation in AGS cells and modulates the activity of STAT3 regulatory molecules. H. pylori secretome could affect neurological compartments by promoting STAT3 activation and inducing the expression of AD-associated signature markers. Further, pSTAT-3 inhibition mitigates the H. pylori associated neuroinflammation and amyloid pathology.

From macroautophagy to mitophagy: Unveiling the hidden role of mitophagy in gastrointestinal disorders

In this editorial, we comment on an article titled “Morphological and biochemical characteristics associated with autophagy in gastrointestinal diseases”, which was published in a recent issue of the World Journal of Gastroenterology. We focused on the statement that “autophagy is closely related to the digestion, secretion, and regeneration of gastrointestinal cells”. With advancing research, autophagy, and particularly the pivotal role of the macroautophagy in maintaining cellular equilibrium and stress response in the gastrointestinal system, has garnered extensive study. However, the significance of mitophagy, a unique selective autophagy pathway with ubiquitin-dependent and independent variants, should not be overlooked. In recent decades, mitophagy has been shown to be closely related to the occurrence and development of gastrointestinal diseases, especially inflammatory bowel disease, gastric cancer, and colorectal cancer. The interplay between mitophagy and mitochondrial quality control is crucial for elucidating disease mechanisms, as well as for the development of novel treatment strategies. Exploring the pathogenesis behind gastrointestinal diseases and providing individualized and efficient treatment for patients are subjects we have been exploring. This article reviews the potential mechanism of mitophagy in gastrointestinal diseases with the hope of providing new ideas for diagnosis and treatment.

Autophagy induced by Helicobacter Pylori infection can lead to gastric cancer dormancy, metastasis, and recurrence: new insights

According to the findings of recent research, Helicobacter Pylori (H. pylori) infection is not only the primary cause of gastric cancer (GC), but it is also linked to the spread and invasion of GC through a number of processes and factors that contribute to virulence. In this study, we discussed that H. pylori infection can increase autophagy in GC tumor cells, leading to poor prognosis in such patients. Until now, the main concerns have been focused on H. pylori's role in GC development. According to our hypothesis, however, H. pylori infection may also lead to GC dormancy, metastasis, and recurrence by stimulating autophagy. Therefore, understanding how H. pylori possess these processes through its virulence factors and various microRNAs can open new windows for providing new prevention and/or therapeutic approaches to combat GC dormancy, metastasis, and recurrence which can occur in GC patients with H. pylori infection with targeting autophagy and eradicating H. pylori infection.

The interaction between autophagy, Helicobacter pylori, and gut microbiota in gastric carcinogenesis

Chronic infection with Helicobacter pylori is the primary risk factor for the development of gastric cancer. Hindering our ability to comprehend the precise role of autophagy during H. pylori infection is the complexity of context-dependent autophagy signaling pathways. Recent and ongoing progress in understanding H. pylori virulence allows new frontiers of research for the crosstalk between autophagy and H. pylori. Novel approaches toward discovering autophagy signaling networks have further revealed their critical influence on the structure of gut microbiota and the metabolome. Here we intend to present a holistic view of the perplexing role of autophagy in H. pylori pathogenesis and carcinogenesis. We also discuss the intermediate role of autophagy in H. pylori-mediated modification of gut inflammatory responses and microbiota structure.

Ready, STAT3, Go! Bacteria in the race for M2 macrophage polarisation

Despite macrophages representing professional immune cells that are integral to the host defences against microbial threats, several intracellular bacteria not only infect, but survive, replicate and often persist in these cells. This is perhaps possible because not all macrophages are the same. Instead, macrophages are loosely divided into two classes: the M1 'classically activated' pro-inflammatory subset and the M2 'alternatively activated' cells that are generally anti-inflammatory and infection-permissive. In this review, we summarise recent findings explaining how several intracellular pathogens, often using secreted effectors, rewire host circuitry in favour of an anti-inflammatory niche. A common theme is the phosphorylation and activation of the signal transducer and activator of transcription-3 (STAT3) transcription factor. We describe and compare the diverse mechanisms employed and reflect how such non-canonical processes may have evolved to circumvent regulation by the host, providing a potent means by which different pathogens manipulate the cells they infect.

Traditional Chinese medicine for transformation of gastric precancerous lesions to gastric cancer: A critical review

Gastric cancer (GC) is a common gastrointestinal tumor. Gastric precancerous lesions (GPL) are the last pathological stage before normal gastric mucosa transforms into GC. However, preventing the transformation from GPL to GC remains a challenge. Traditional Chinese medicine (TCM) has been used to treat gastric disease for millennia. A series of TCM formulas and active compounds have shown therapeutic effects in both GC and GPL. This article reviews recent progress on the herbal drugs and pharmacological mechanisms of TCM in preventing the transformation from GPL to GC, especially focusing on anti-inflammatory, anti-angiogenesis, proliferation, and apoptosis. This review may provide a meaningful reference for the prevention of the transformation from GPL to GC using TCM.

Activation of PINK1-mediated mitophagy protects bovine mammary epithelial cells against lipopolysaccharide-induced mitochondrial and inflammatory damage in vitro

Increased metabolic stress during early lactation results in damage of mitochondria and inflammatory responses in bovine mammary epithelial cells, both of which could be aggravated by inhibition of mitophagy. PTEN-induced putative kinase 1 (PINK1)-mediated mitophagy is essential in the removal of damaged mitochondria and the regulation of inflammatory responses. The aim of the present study was to elucidate the role of PINK1-mediated mitophagy on mitochondrial damage and inflammatory responses in bovine mammary epithelial cells challenged with lipopolysaccharide (LPS). Exogenous LPS activated mitophagy and led to lower protein abundance of oxidative phosphorylation (OXPHOS) complexes (COI-V) and lower oxygen consumption rate (OCR) along with increased mitochondrial reactive oxygen species (Mito-ROS) content. These effects were also associated with increased protein abundance of Nucleotide-binding oligomerization domain-like receptor containing pyrin domain 3 (NLRP3) in a time-dependent manner. Pretreatment with 3-Methyladenine (3-MA) or knockdown of PINK1 aggravated the downregulation of COI-V protein abundance, the increase in Mito-ROS content, and the protein abundance of NLRP3, Cleaved-Caspase-1 and IL-1β induced by LPS. Overexpression of PINK1 activated mitophagy and alleviated LPS-induced NLRP3 inflammasome activation by reducing Mito-ROS production. Overall, the data suggested that PINK1-mediated mitophagy is a crucial anti-inflammatory mechanism that removes damaged mitochondria in bovine mammary epithelial cells experiencing an increased inflammatory load.

Ciclopirox drives growth arrest and autophagic cell death through STAT3 in gastric cancer cells

Ciclopirox (CPX), an antifungal drug, has recently been identified as a promising agent for cancer treatment. However, the effects and underlying mechanism of CPX as an antitumor agent of gastric cancer (GC) remain largely unknown. Here, we found that CPX dramatically suppresses GC xenograft growth in vitro via inhibiting proliferation and stimulating autophagic cell death rather than apoptosis. Moreover, CPX (20 mg/kg, intraperitoneally) substantially inhibits GC xenograft tumor growth in vivo. Mechanistically, CPX promotes growth arrest and autophagic cell death through suppressing the phosphorylation of signal transducers and activators of transcription 3 (STAT3) at tyrosine 705 (Tyr705) and serine 727 (Ser727) sites, respectively. Additionally, CPX induces STAT3 ubiquitination, which subsequently leads to a decrease in the p-STAT3 (Ser727) level. On the other hand, CPX represses the p-STAT3 (Tyr705) level via p-Src (Tyr416) inhibition. Collectively, our findings unmask a novel mechanism by which CPX regulates growth and autophagic cell death in GC cells via regulating the phosphorylation of STAT3 both at Tyr705 and Ser727 residues, and suggest that CPX may be a potential treatment for GC.

Anxiolytic and antidepressive potentials of rosmarinic acid: A review with a focus on antioxidant and anti-inflammatory effects

Depression and anxiety are the most prevalent neuropsychiatric disorders that have emerged as global health concerns. Anxiolytic and antidepressant drugs, such as benzodiazepines, selective serotonin reuptake inhibitors, monoamine oxidase inhibitors, and tricyclics, are the first line used in treating anxiety and depression. Although these drugs lack efficacy and have a delayed response time and numerous side effects, their widespread abuse and market continue to grow. Over time, traditional practices using natural and phytochemicals as alternative therapies to chemical drugs have emerged to treat many pathological conditions, including anxiety and depression. Recent preclinical studies have demonstrated that the phenolic compound, rosmarinic acid, is effective against several neuropsychiatric disorders, including anxiety and depression. In addition, rosmarinic acid showed various pharmacological effects, such as cardioprotective, hepatoprotective, lung protective, antioxidant, anti-inflammatory, and neuroprotective effects. However, the potentialities of the use of rosmarinic acid in the treatment of nervous system-related disorders, such as anxiety and depression, are less or not yet reviewed. Therefore, the purpose of this review was to present several preclinical and clinical studies, when available, from different databases investigating the effects of rosmarinic acid on anxiety and depression. These studies showed that rosmarinic acid produces advantageous effects on anxiety and depression through its powerful antioxidant and anti-inflammatory properties. This review will examine and discuss the possibility that the anxiolytic and anti-depressive effects of rosmarinic acid could be associated with its potent antioxidant and anti-inflammatory activities.

Vacuolating Cytotoxin A Triggers Mitophagy in Helicobacter pylori-Infected Human Gastric Epithelium Cells

Helicobacter pylori (H. pylori)-derived vacuolating cytotoxin A (VacA) causes damage to various organelles, including mitochondria, and induces autophagy and cell death. However, it is unknown whether VacA-induced mitochondrial damage can develop into mitophagy. In this study, we found that H. pylori, H. pylori culture filtrate (HPCF), and VacA could activate autophagy in a gastric epithelial cell line (GES-1). VacA-caused mitochondrial depolarization retards the import of PINK1 into the damaged mitochondria and evokes mitophagy. And, among mass spectrometry (LC-MS/MS) identified 25 mitochondrial proteins bound with VacA, Tom20, Tom40, and Tom70, TOM complexes responsible for PINK1 import, were further identified as having the ability to bind VacA in vitro using pull-down assay, co-immunoprecipitation, and protein–protein docking. Additionally, we found that the cell membrane protein STOM and the mitochondrial inner membrane protein PGAM5 also interacted with VacA. These findings suggest that VacA captured by STOM forms endosomes to enter cells and target mitochondria. Then, VacA is transported into the mitochondrial membrane space through the TOM complexes, and PGAM5 aids in inserting VacA into the inner mitochondrial membrane to destroy the membrane potential, which promotes PINK1 accumulation and Parkin recruitment to induce mitophagy. This study helps us understand VacA entering mitochondria to induce the mitophagy process.

Downregulation of STK25 promotes autophagy via the Janus kinase 2/signal transducer and activator of transcription 3 pathway in colorectal cancer

Autophagy plays a crucial role in colorectal cancer (CRC) development. Our previous study suggested that serine/threonine protein kinase 25 (STK25) regulates aerobic glycolysis in CRC cells. Glycolysis modulates cellular autophagy during tumor growth; however, the role of STK25 in autophagy remains unclear. In this study, we found that STK25 expression was decreased in CRC tissues and CRC patients with high STK25 expression had a favorable prognosis. Functional assays suggested that STK25 inhibition promoted autophagy in CRC cells. Overexpression of STK25 exhibited the opposite effects. Moreover, the results of western blot demonstrated that silencing STK25 induced autophagy by activating the JAK2/STAT3 pathway. Therefore, STK25 could be a potential indicator for therapies targeting the JAK2/STAT3 pathway in CRC.

Helicobacter pylori Infection of Primary Human Monocytes Boosts Subsequent Immune Responses to LPS

Infection with Helicobacter pylori (H. pylori) affects almost half of the world's population and is a major cause of stomach cancer. Although immune cells react strongly to this gastric bacterium, H. pylori is still one of the rare pathogens that can evade elimination by the host and cause chronic inflammation. In the present study, we characterized the inflammatory response of primary human monocytes to repeated H. pylori infection and their responsiveness to an ensuing bacterial stimulus. We show that, although repeated stimulations with H. pylori do not result in an enhanced response, H. pylori-primed monocytes are hyper-responsive to an Escherichia coli-lipopolysaccharide (LPS) stimulation that takes place shortly after infection. This hyper-responsiveness to bacterial stimuli is observed upon infection with viable H. pylori only, while heat-killed H. pylori fails to boost both cytokine secretion and STAT activation in response to LPS. When the secondary challenge occurs several days after the primary infection with live bacteria, H. pylori-infected monocytes lose their hyper-responsiveness. The observation that H. pylori makes primary human monocytes more susceptible to subsequent/overlapping stimuli provides an important basis to better understand how H. pylori can maintain chronic inflammation and thus contribute to gastric cancer progression.

Integrative Analysis of Deregulated miRNAs Reveals Candidate Molecular Mechanisms Linking H. pylori Infected Peptic Ulcer Disease with Periodontitis

Objective

Periodontitis is a highly prevalent oral infectious disease and has been increasingly associated with H. pylori infection, gastric inflammation, and gastric cancer but little is known about epigenetic machinery underlying this potentially bidirectional association. The present study is aimed at identifying key deregulated miRNA, their associated genes, signaling pathways, and compounds linking periodontitis with H. pylori-associated peptic ulcer disease.

Methods

miRNA expression datasets for periodontitis-affected and H. pylori-associated peptic ulcer disease-affected tissues were sought from the GEO database. Differentially expressed miRNA (DEmiRNAs) were identified and the overlapping, shared-DEmiRNA between both datasets were determined. Shared-DEmiRNA-target networks construction and functional analyses were constructed using miRNet 2.0, including shared-DEmiRNA-gene, shared-DEmiRNA-transcription factor (TF), and shared-DEmiRNA-compound networks. Functional enrichment analysis for shared DEmiRNA-gene and shared DEmiRNA-TF networks was performed using the KEGG, Reactome, and Geno Ontology (GO) pathways.

Results

11 shared-DEmiRNAs were identified, among which 9 showed similar expression patterns in both diseases, and 7 were overexpressed. miRNA hsa-hsa-mir-155-5p and hsa-mir-29a-3p were top miRNA nodes in both gene and TF networks. The topmost candidate miRNA-deregulated genes were PTEN, CCND1, MDM2, TNRC6A, and SCD while topmost deregulated TFs included STAT3, HIF1A, EZH2, CEBPA, and RUNX1. Curcumin, 5-fluorouracil, and the gallotanin 1,2,6-Tri-O-galloyl-beta-D-glucopyranose emerged as the most relevant linkage compound targets. Functional analyses revealed multiple cancer-associated pathways, PI3K pathways, kinase binding, and transcription factor binding among as enriched by the network-associated genes and TFs.

Conclusion

Integrative analysis of deregulated miRNAs revealed candidate molecular mechanisms comprising of top miRNA, their gene, and TF targets linking H. pylori-infected peptic ulcer disease with periodontitis and highlighted compounds targeting both diseases. These findings provide basis for directing future experimental research.

Chk1 inhibition potently blocks STAT3 tyrosine705 phosphorylation, DNA binding activity, and activation of downstream targets in human multiple myeloma cells

The relationship between the checkpoint kinase Chk1 and the STAT3 pathway was examined in multiple myeloma (MM) cells. Gene expression profiling of U266 cells exposed to low (nM) Chk1 inhibitor (PF-477736) concentrations revealed STAT3 pathway-related gene down-regulation (e.g., BCL-XL, MCL-1, c-Myc), findings confirmed by RT-PCR. This was associated with marked inhibition of STAT3 Tyr705 (but not Ser727) phosphorylation, dimerization, nuclear localization, DNA binding, STAT3 promoter activity by ChIP assay, and down-regulation of STAT-3-dependent proteins. Similar findings were obtained in other MM cells and with alternative Chk1 inhibitors (e.g., prexasertib, CEP3891). While PF did not reduce GP130 expression or modify SOCS or PRL-3 phosphorylation, the phosphatase inhibitor pervanadate antagonized PF-mediated Tyr705 dephosphorylation. Significantly, PF attenuated Chk1-mediated STAT3 phosphorylation in in vitro assays. SPR analysis suggested Chk1/STAT3 interactions and PF reduced Chk1/STAT3 co-immunoprecipitation. Chk1 CRISPR knockout or shRNA knockdown cells also displayed STAT3 inactivation and STAT-3-dependent protein down-regulation. Constitutively active STAT3 diminished PF-mediated STAT3 inactivation and down-regulate STAT3-dependent proteins while significantly reducing PF-induced DNA damage (rH2A.X formation) and apoptosis. Exposure of cells with low basal phospho-STAT3 expression to IL-6 or human stromal cell conditioned medium activated STAT3, an event attenuated by Chk1 inhibitors. PF also inactivated STAT3 in primary human CD138+ MM cells and tumors extracted from an NSG MM xenograft model while inhibiting tumor growth. Implications: These findings identify a heretofore unrecognized link between the Chk1 and STAT3 pathways and suggest that Chk1 pathway inhibitors warrant attention as novel and potent candidate STAT3 antagonists in myeloma.

Role of autophagy in gastric carcinogenesis

Gastric cancer represents a common and highly fatal malignancy, and thus a pathophysiology-based reconsideration is necessary, given the absence of efficient therapeutic regimens. In this regard, emerging data reveal a significant role of autophagy in gastric oncogenesis, progression, metastasis and chemoresistance. Although autophagy comprises a normal primordial process, ensuring cellular homeostasis under energy depletion and stress conditions, alterations at any stage of the complex regulatory system could stimulate a tumorigenic and promoting cascade. Among others, Helicobacter pylori infection induces a variety of signaling molecules modifying autophagy, during acute infection or after chronic autophagy degeneration. Subsequently, defective autophagy allows malignant transformation and upon cancer establishment, an overactive autophagy is stimulated. This overexpressed autophagy provides energy supplies and resistance mechanisms to gastric cancer cells against hosts defenses and anticancer treatment. This review interprets the implicated autophagic pathways in normal cells and in gastric cancer to illuminate the potential preventive, therapeutic and prognostic benefits of understanding and intervening autophagy.

Autophagy in Gastric Mucosa: The Dual Role and Potential Therapeutic Target

The incidence of stomach diseases is very high, which has a significant impact on human health. Damaged gastric mucosa is more vulnerable to injury, leading to bleeding and perforation, which eventually aggravates the primary disease. Therefore, the protection of gastric mucosa is crucial. However, existing drugs that protect gastric mucosa can cause nonnegligible side effects, such as hepatic inflammation, nephritis, hypoacidity, impotence, osteoporotic bone fracture, and hypergastrinemia. Autophagy, as a major intracellular lysosome-dependent degradation process, plays a key role in maintaining intracellular homeostasis and resisting environmental pressure, which may be a potential therapeutic target for protecting gastric mucosa. Recent studies have demonstrated that autophagy played a dual role when gastric mucosa exposed to biological and chemical factors. More indepth studies are needed on the protective effect of autophagy in gastric mucosa. In this review, we focus on the mechanisms and the dual role of various biological and chemical factors regulating autophagy, such as Helicobacter pylori, virus, and nonsteroidal anti-inflammatory drugs. And we summarize the pathophysiological properties and pharmacological strategies for the protection of gastric mucosa through autophagy.

Helicobacter pylori-induced protein tyrosine phosphatase receptor type C as a prognostic biomarker for gastric cancer

Background

Helicobacter pylori (H. pylori) infection is closely associated with the tumorigenesis of gastric cancer. The aim of the present study was to identify the key regulator in H. pylori-related gastric cancer and to study the expression level and clinical value of the indicated key regulator in gastric cancer.

Methods

The GSE6143 dataset was used to identify differentially expressed genes (DEGs) with limma R package, and enrichment analysis was done using the Metascape web-based portal. The protein-protein interaction analysis was done using Search Tool for the Retrieval of Interacting Genes/Proteins. Gastric adenocarcinoma AGS and BGC-823 cells were treated with H. pylori strain 26695 to construct the in vitro H. pylori infection model, and quantitative reverse transcription polymerase chain reaction was used to analyze the mRNA levels of indicated genes. The correlation analysis between two genes in gastric cancer was done by GEPIA. Furthermore, the PTPRC expression by pathological features analysis was conducted in UALCAN, an easy to use, interactive web-portal (http://ualcan.path.uab.edu). The survival analysis for gastric cancer, based on PTPRC expression levels, was done using the Kaplan-Meier plotter.

Results

DEGs in gastric mucosa with or without H. pylori infection were identified and enriched in immune-related pathways and cancer pathways. The protein-protein interaction analysis confirmed the enrichment analysis of gene ontology. H. pylori strain 26695 exposure also confirmed the alteration of gene expression levels in AGS and BGC-823 cells. PTPRC was co-expressed with CSF2RB and TNFRSF7, indicating a significant positive correlation in gastric cancer. PTPRC was overexpressed in gastric cancer, and the overexpression of PTPRC was positively correlated with the progression of gastric cancer. Furthermore, the high expression of PTPRC could act as a poor prognostic factor for gastric cancer patients, especially for those at advanced stage.

Conclusions

H. pylori-induced PTPRC is overexpressed in gastric cancer, and the overexpression of PTPRC is positively associated with the development of gastric cancer. The high expression of PTPRC could serve as poor prognostic biomarker for gastric cancer patients, especially for those at advanced stage. H. pylori-induced PTPRC is a prognostic biomarker for gastric cancer.

MiR-29a Alleviates High Glucose-induced Inflammation and Mitochondrial Dysfunction via Modulation of IL-6/STAT3 in Diabetic Cataracts

Background: This in vitro study was designed to reveal the role of miR-29a in high glucose-induced cellular injury through the modulation of IL-6/STAT3 in diabetic cataracts.Methods: The expression of miR-29a and STAT3 in the lens capsules of patients with or without diabetes was determined by RT-PCR. The levels of the IL-6 proinflammatory cytokine in the aqueous humor were detected by ELISA. HLE B-3 cells were cultured in normal glucose (NG; 5 mM) or high glucose (HG; 40 mM). After transfection with miR-29a, si-STAT3, or a negative control vector, the levels of IL-6 and STAT3 were detected. A CCK-8 assay was used to determine cell viability. We used flow cytometry to assess changes in reactive oxygen species (ROS) production, mitochondrial membrane potential (MMP), and apoptosis induced by oxidative stress. Western blotting was used to determine the expression of the oxidative injury markers superoxide dismutase (SOD) and malondialdehyde (MDA) and the apoptosis markers Bcl-2 and Bax.Results: Reduced miR-29a, increased STAT3 expression, and IL-6 release were demonstrated in the lens capsules and aqueous humor of patients with diabetes. The stimulation of apoptosis and the loss of MMP induced by HG were attenuated by transfection with a miR-29a mimic and si-STAT3. ROS production, increased MDA content, decreased SOD activity, and upregulation of the apoptotic proteins Bcl-2/Bax were also partially alleviated by miR-29a overexpression, which shows their roles in oxidative injury. Furthermore, transfection with a STAT3 overexpression vector reversed the effects of miR-29a.Conclusions: In conclusion, miR-29a mitigated HG-induced oxidative injury and exerted protective effects via IL-6/STAT3 signaling. Thus, miR-29a may be a potential therapeutic agent for diabetic cataracts.

Bridging the gap - a new role for STAT3 in TLR4-mediated metabolic reprogramming

Balic et al. describe a new role for STAT3 in TLR4 signalling in macrophages, linking LPS mediated activation of this innate immune receptor to phosphorylation of mitochondrial STAT3, resulting in distinct metabolic reprogramming.