AMP-activated protein kinase restricts IFN-γ signaling

Insights into the mechanism of action of pterostilbene against influenza A virus-induced acute lung injury

BACKGROUND

Severe respiratory system illness caused by influenza A virus infection is associated with excessive inflammation and abnormal apoptosis in alveolar epithelial cells (AEC). However, there are limited therapeutic options for influenza-associated lung inflammation and apoptosis. Pterostilbene (PTE, trans-3,5-dimethoxy-4-hydroxystilbene) is a dimethylated analog of resveratrol that has been reported to limit influenza A virus infection by promoting antiviral innate immunity, but has not been studied for its protective effects on virus-associated inflammation and injury in AEC.

PURPOSE

Our study aimed to investigate the protective effects and underlying mechanisms of PTE in modulating inflammation and apoptosis in AEC, as well as its effects on macrophage polarization during influenza virus infection.

STUDY DESIGN AND METHODS

A murine model of influenza A virus-mediated acute lung injury was established by intranasal inoculation with 5LD50 of mouse-adapted H1N1 viruses. Hematoxylin and eosin staining, immunofluorescence, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, western blotting, Luminex and flow cytometry were performed.

RESULTS

PTE effectively mitigated lung histopathological changes and injury induced by H1N1 viruses in vivo. These beneficial effects of PTE were attributed to the suppression of inflammation and apoptosis in AEC, as well as the modulation of M1 macrophage polarization. Mechanistic investigations revealed that PTE activated the phosphorylated AMP-activated protein kinase alpha (P-AMPKα)/sirtui1 (Sirt1)/PPARγ coactivator 1-alpha (PGC1α) signal axis, leading to the inhibition of nuclear factor kappa-B (NF-κB) and p38 mitogen-activated protein kinase (MAPK) signaling induced by H1N1 viruses, thereby attenuating inflammation and apoptosis in AEC. PTE also forced activation of the P-AMPKα/Sirt1/PGC1α signal axis in RAW264.7 cells, counteracting the activation of phosphorylated signal transducer and activator of transcription 1 (P-STAT1) induced by H1N1 viruses and the augment of P-STAT1 activation in RAW264.7 cells with interferon-gamma (IFN-γ) pretreatment before viral infection, thereby reducing H1N1 virus-mediated M1 macrophage polarization as well as the enhancement of macrophages into M1 phenotypes elicited by IFN-γ pretreatment. Additionally, the promotion of the transition of macrophages towards the M2 phenotype by PTE was also related to activation of the P-AMPKα/Sirt1/PGC1α signal axis. Moreover, co-culturing non-infected AEC with H1N1 virus-infected RAW264.7 cells in the presence of PTE inhibited apoptosis and tight junction disruption, which was attributed to the suppression of pro-inflammatory mediators and pro-apoptotic factors in an AMPKα-dependent manner.

CONCLUSION

In conclusion, our findings suggest that PTE may serve as a promising novel therapeutic option for treating influenza-associated lung injury. Its ability to suppress inflammation and apoptosis in AEC, modulate macrophage polarization, and preserve alveolar epithelial cell integrity highlights its potential as a therapeutic agent in influenza diseases.

PPARA ameliorates sepsis-induced myocardial injury via promoting macrophage M2 polarization by interacting with DUSP1

Background

The morbidity and mortality of sepsis are increasing year by year. Statistically, 40-50% of patients with sepsis have concomitant myocardial injury, and its mortality rate is higher than that of patients with sepsis only. Therefore, it is of great significance to elucidate the mechanism of sepsis-induced myocardial injury.

Methods and results

Human monocytes (THP-1) were used to induce M0 macrophages, followed by treated with lipopolysaccharide (LPS). Cardiomyocytes (AC16) were co-cultured with the conditioned medium of LPS-induced macrophages to induce injury. Quantitative real-time PCR was employed to detect the mRNA levels of peroxisome proliferator-activated receptor α (PPARA) and dual specificity phosphatase 1 (DUSP1). Protein levels of PPARA, macrophage polarization-related markers, apoptosis-related markers, mitochondria-related proteins, and DUSP1 were analyzed by Western blot. Flow cytometry was used to assess M1/M2 cell rates and apoptosis. Low PPARA expression could serve as a biomarker for patients with sepsis. PPARA overexpression enhanced M2 polarization and suppressed M1 polarization in LPS-induced macrophages, and it could alleviate cardiomyocyte injury in co-cultured system. PPARA bound to the DUSP1 promoter region and facilitated its expression. DUSP1 knockdown reversed the effect of PPARA overexpression on M2 polarization and cardiomyocyte injury.

Conclusion

PPARA attenuated cardiomyocyte injury by promoting macrophage M2 polarization through increasing DUSP1 expression, suggesting that PPARA might be a therapy target for sepsis-induced myocardial injury.

AMPK-a key factor in crosstalk between tumor cell energy metabolism and immune microenvironment?

Immunotherapy has now garnered significant attention as an essential component in cancer therapy during this new era. However, due to immune tolerance, immunosuppressive environment, tumor heterogeneity, immune escape, and other factors, the efficacy of tumor immunotherapy has been limited with its application to very small population size. Energy metabolism not only affects tumor progression but also plays a crucial role in immune escape. Tumor cells are more metabolically active and need more energy and nutrients to maintain their growth, which causes the surrounding immune cells to lack glucose, oxygen, and other nutrients, with the result of decreased immune cell activity and increased immunosuppressive cells. On the other hand, immune cells need to utilize multiple metabolic pathways, for instance, cellular respiration, and oxidative phosphorylation pathways to maintain their activity and normal function. Studies have shown that there is a significant difference in the energy expenditure of immune cells in the resting and activated states. Notably, competitive uptake of glucose is the main cause of impaired T cell function. Conversely, glutamine competition often affects the activation of most immune cells and the transformation of CD4+T cells into inflammatory subtypes. Excessive metabolite lactate often impairs the function of NK cells. Furthermore, the metabolite PGE2 also often inhibits the immune response by inhibiting Th1 differentiation, B cell function, and T cell activation. Additionally, the transformation of tumor-suppressive M1 macrophages into cancer-promoting M2 macrophages is influenced by energy metabolism. Therefore, energy metabolism is a vital factor and component involved in the reconstruction of the tumor immune microenvironment. Noteworthy and vital is that not only does the metabolic program of tumor cells affect the antigen presentation and recognition of immune cells, but also the metabolic program of immune cells affects their own functions, ultimately leading to changes in tumor immune function. Metabolic intervention can not only improve the response of immune cells to tumors, but also increase the immunogenicity of tumors, thereby expanding the population who benefit from immunotherapy. Consequently, identifying metabolic crosstalk molecules that link tumor energy metabolism and immune microenvironment would be a promising anti-tumor immune strategy. AMPK (AMP-activated protein kinase) is a ubiquitous serine/threonine kinase in eukaryotes, serving as the central regulator of metabolic pathways. The sequential activation of AMPK and its associated signaling cascades profoundly impacts the dynamic alterations in tumor cell bioenergetics. By modulating energy metabolism and inflammatory responses, AMPK exerts significant influence on tumor cell development, while also playing a pivotal role in tumor immunotherapy by regulating immune cell activity and function. Furthermore, AMPK-mediated inflammatory response facilitates the recruitment of immune cells to the tumor microenvironment (TIME), thereby impeding tumorigenesis, progression, and metastasis. AMPK, as the link between cell energy homeostasis, tumor bioenergetics, and anti-tumor immunity, will have a significant impact on the treatment and management of oncology patients. That being summarized, the main objective of this review is to pinpoint the efficacy of tumor immunotherapy by regulating the energy metabolism of the tumor immune microenvironment and to provide guidance for the development of new immunotherapy strategies.

AMP-activated protein kinase as a mediator of mitochondrial dysfunction of multiple sclerosis in animal models: A systematic review

Multiple sclerosis (MS) is a chronic central nervous system (CNS) disorder characterized by demyelination, neuronal damage, and oligodendrocyte depletion. Reliable biomarkers are essential for early diagnosis and disease management. Emerging research highlights the role of mitochondrial dysfunction and oxidative stress in CNS disorders, including MS, in which mitochondria are central to the degenerative process. Adenosine monophosphate-activated protein kinase (AMPK) regulates the mitochondrial energy balance and initiates responses in neurodegenerative conditions. This systematic review, following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, aimed to comprehensively assess the literature on AMPK pathways, mitochondrial dysfunction, and in vivo studies using MS animal models. The search strategy involved the use of AMPK syntaxes, MS syntaxes, and animal model syntaxes. The PubMed, Scopus, Web of Science, and Google Scholar databases were systematically searched on August 26, 2023 without publication year restrictions. The review identified and analyzed relevant papers to provide a comprehensive overview of the current state of related research. Eight studies utilizing various interventions and methodological approaches were included. Risk of bias assessment revealed some areas of low risk but lacked explicit reporting in others. These studies collectively revealed a complex relationship between AMPK, mitochondrial dysfunction, and MS pathogenesis, with both cuprizone and experimental autoimmune encephalomyelitis models demonstrating associations between AMPK and mitochondrial disorders, including oxidative stress and impaired expression of mitochondrial genes. These studies illuminate the multifaceted role of AMPK in MS animal models, involving energy metabolism, inflammatory processes, oxidative stress, and gene regulation leading to mitochondrial dysfunction. However, unanswered questions about its mechanisms and clinical applications underscore the need for further research to fully harness its potential in addressing MS-related mitochondrial dysfunction.

Th1 cells contribute to retinal ganglion cell loss in glaucoma in a VCAM-1-dependent manner

Glaucoma is a complex neurodegenerative disorder characterized by the progressive loss of retinal ganglion cells (RGC) and optic nerve axons, leading to irreversible visual impairment. Despite its clinical significance, the underlying mechanisms of glaucoma pathogenesis remain poorly understood. In this study, we aimed to unravel the multifaceted nature of glaucoma by investigating the interaction between T cells and retinas. By utilizing clinical samples, murine glaucoma models, and T cell transfer models, we made several key findings. Firstly, we observed that CD4+ T cells from glaucoma patients displayed enhanced activation and a bias towards T helper (Th) 1 responses, which correlated with visual impairment. Secondly, we identified the infiltration of Th1 cells into the retina, where they targeted RGC and integrated into the pro-inflammatory glial network, contributing to progressive RGC loss. Thirdly, we discovered that circulating Th1 cells upregulated vascular cell adhesion protein 1 (VCAM-1) on retinal microvessels, facilitating their entry into the neural retina. Lastly, we found that Th1 cells underwent functional reprogramming before reaching the retina, acquiring a phenotype associated with lymphocyte migration and neurodegenerative diseases. Our study provides novel insights into the role of peripheral CD4+ T cells in glaucoma pathogenesis, shedding light on the mechanisms underlying their infiltration into the retina and offering potential avenues for innovative therapeutic interventions in this sight-threatening disease.

AMPKα1 Deficiency in Astrocytes from a Rat Model of ALS Is Associated with an Altered Metabolic Resilience

Alterations in the activity of the regulator of cell metabolism AMP-activated protein kinase (AMPK) have been reported in motor neurons from patients and animal models of amyotrophic lateral sclerosis (ALS). Considering the key role played by astrocytes in modulating energy metabolism in the nervous system and their compromised support towards neurons in ALS, we examined whether a putative alteration in AMPK expression/activity impacted astrocytic functions such as their metabolic plasticity and glutamate handling capacity. We found a reduced expression of AMPK mRNA in primary cultures of astrocytes derived from transgenic rats carrying an ALS-associated mutated superoxide dismutase (hSOD1G93A). The activation of AMPK after glucose deprivation was reduced in hSOD1G93A astrocytes compared to non-transgenic. This was accompanied by a lower increase in ATP levels and increased vulnerability to this insult, although the ATP production rate did not differ between the two cell types. Furthermore, soliciting the activity of glutamate transporters was found to induce similar AMPK activity in these cells. However, manipulation of AMPK activity did not influence glutamate transport. Together, these results suggest that the altered AMPK responsiveness in ALS might be context dependent and may compromise the metabolic adaptation of astrocytes in response to specific cellular stress.

Cardiovascular Functions of Ena/VASP Proteins: Past, Present and Beyond

Actin binding proteins are of crucial importance for the spatiotemporal regulation of actin cytoskeletal dynamics, thereby mediating a tremendous range of cellular processes. Since their initial discovery more than 30 years ago, the enabled/vasodilator-stimulated phosphoprotein (Ena/VASP) family has evolved as one of the most fascinating and versatile family of actin regulating proteins. The proteins directly enhance actin filament assembly, but they also organize higher order actin networks and link kinase signaling pathways to actin filament assembly. Thereby, Ena/VASP proteins regulate dynamic cellular processes ranging from membrane protrusions and trafficking, and cell-cell and cell-matrix adhesions, to the generation of mechanical tension and contractile force. Important insights have been gained into the physiological functions of Ena/VASP proteins in platelets, leukocytes, endothelial cells, smooth muscle cells and cardiomyocytes. In this review, we summarize the unique and redundant functions of Ena/VASP proteins in cardiovascular cells and discuss the underlying molecular mechanisms.

NOD-like receptor NLRC5 promotes neuroinflammation and inhibits neuronal survival in Parkinson's disease models

Parkinson's disease (PD) is mainly characterized by the progressive degeneration of dopaminergic neurons in the substantia nigra pars compacta (SNpc) and neuroinflammation mediated by overactivated microglia and astrocytes. NLRC5 (nucleotide-binding oligomerization domain-like receptor family caspase recruitment domain containing 5) has been reported to participate in various immune disorders, but its role in neurodegenerative diseases remains unclear. In the current study, we found that the expression of NLRC5 was increased in the nigrostriatal axis of mice with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine hydrochloride (MPTP)-induced PD, as well as in primary astrocytes, microglia and neurons exposed to different neurotoxic stimuli. In an acute MPTP-induced PD model, NLRC5 deficiency significantly reduced dopaminergic system degeneration and ameliorated motor deficits and striatal inflammation. Furthermore, we found that NLRC5 deficiency decreased the expression of the proinflammatory genes IL-1β, IL-6, TNF-α and COX2 in primary microglia and primary astrocytes treated with neuroinflammatory stimuli and reduced the inflammatory response in mixed glial cells in response to LPS treatment. Moreover, NLRC5 deficiency suppressed activation of the NF-κB and MAPK signaling pathways and enhanced the activation of AKT-GSK-3β and AMPK signaling in mixed glial cells. Furthermore, NLRC5 deficiency increased the survival of primary neurons treated with MPP⁺ or conditioned medium from LPS-stimulated mixed glial cells and promoted activation of the NF-κB and AKT signaling pathways. Moreover, the mRNA expression of NLRC5 was decreased in the blood of PD patients compared to healthy subjects. Therefore, we suggest that NLRC5 promotes neuroinflammation and dopaminergic degeneration in PD and may serve as a marker of glial activation.

Interferon Gamma-Inducible NAMPT in Melanoma Cells Serves as a Mechanism of Resistance to Enhance Tumor Growth

(1) Background: Immune cells infiltrate the tumor microenvironment and secrete inflammatory cytokines, including interferons (IFNs), to drive antitumor responses and promote tumor clearance. However, recent evidence suggests that sometimes, tumor cells can also harness IFNs to enhance growth and survival. The essential NAD+ salvage pathway enzyme nicotinamide phosphoribosyltransferase (NAMPT) gene is constitutively expressed in cells during normal homeostasis. However, melanoma cells have higher energetic demands and elevated NAMPT expression. We hypothesized that interferon gamma (IFNγ) regulates NAMPT in tumor cells as a mechanism of resistance that impedes the normal anti-tumorigenic effects of IFNγ. (2) Methods: Utilizing a variety of melanoma cells, mouse models, Crispr-Cas9, and molecular biology techniques, we explored the importance of IFNγ-inducible NAMPT during melanoma growth. (3) Results: We demonstrated that IFNγ mediates the metabolic reprogramming of melanoma cells by inducing Nampt through a Stat1 binding site in the Nampt gene, increasing cell proliferation and survival. Further, IFN/STAT1-inducible Nampt promotes melanoma in vivo. (4) Conclusions: We provided evidence that melanoma cells directly respond to IFNγ by increasing NAMPT levels, improving their fitness and growth in vivo (control n = 36, SBS KO n = 46). This discovery unveils a possible therapeutic target that may improve the efficacy of immunotherapies involving IFN responses in the clinic.

Molecular Mechanisms of T Helper Cell Differentiation and Functional Specialization

Th cells, which orchestrate immune responses to various pathogens, differentiate from naïve CD4 T cells into several subsets that stimulate and regulate immune responses against various types of pathogens, as well as a variety of immune-related diseases. Decades of research have revealed that the fate decision processes are controlled by cytokines, cytokine receptor signaling, and master transcription factors that drive the differentiation programs. Since the Th1 and Th2 paradigm was proposed, many subsets have been added to the list. In this review, I will summarize these events, including the fate decision processes, subset functions, transcriptional regulation, metabolic regulation, and plasticity and heterogeneity. I will also introduce current topics of interest.

Narciclasine ameliorated T cell mediated acute liver injury through activating AMPK pathway

Hepatitis is closely related to cirrhosis and liver cancer, and it is vital that we develop new drugs and identify new drug targets. Traditional Chinese medicine has demonstrated excellent curative effects on liver diseases. The ingredients from Chinese herbals are important source for drug development in the treatment of hepatitis. Here, we found that narciclasine (NCS), a major component extracted from narcissus bulbs, showed hepatoprotective effect against concanavalin A (Con A) induced hepatitis. NCS treatment significantly reduced hepatocyte death, hepatic inflammatory cells infiltration, and serum cytokine levels in Con A challenged mice. We further observed that NCS directly inhibited Con A induced splenocytes proliferation and cytokine production in vitro. RNA-seq results showed that genes related to immune response were upregulated in Con A treated CD4⁺ T cells, which were down-regulated in the presence of NCS. Moreover, the AMPK pathway had been found activated in response to NCS treatment, suggesting a potential target for NCS targets. In conclusion, our results reveal that NCS is a powerful immunosuppressor against T cell activation, thus leading to protection against Con A induced liver injury in mice. These findings provide new insights into the use of natural products in the treatment of autoimmune hepatitis.

Microglia dynamics in aging-related neurobehavioral and neuroinflammatory diseases

Microglia represent the first line of immune feedback in the brain. Beyond immune surveillance, they are essential for maintaining brain homeostasis. Recent research has revealed the microglial cells' spatiotemporal heterogeneity based on their local and time-based functions in brain trauma or disease when homeostasis is disrupted. Distinct "microglial signatures" have been recorded in physiological states and brain injuries, with discrete or sometimes overlapping pro- and anti-inflammatory functions. Microglia are involved in the neurological repair processes, such as neurovascular unit restoration and synaptic plasticity, and manage the extent of the damage due to their phenotype switching. The versatility of cellular phenotypes beyond the classical M1/M2 classification, as well as the double-edge actions of microglia in neurodegeneration, indicate the need for further exploration of microglial cell dynamics and their contribution to neurodegenerative processes. This review discusses the homeostatic functions of different microglial subsets focusing on neuropathological conditions. Also, we address the feasibility of targeting microglia as a therapeutic strategy in neurodegenerative diseases.

Metformin and the risk of dementia based on an analysis of 396,332 participants

Background:

AMPK has attracted widespread interest as a potential therapeutic target for age-related diseases, given its key role in controlling energy homeostasis. Metformin (Met) has historically been used to treat Type 2 diabetes and has been shown to counteract age-related diseases. However, studies regarding the relationship between Met and a variety of age-related classifications of cognitive decline have reported mixed findings.

Objective:

To assess the potential effect of Met on the onset of dementia and discuss the possible biological mechanisms involved.

Methods:

This study was registered in the PROSPERO database (CRD420201251468). PubMed, Embase, and Cochrane Library were searched from inception to 25 May 2021, for population-based cohort studies. Effect estimates with 95% confidence intervals (CIs) were pooled using the random-effects model. Meta-regression and subgroup analyses were performed to explore sources of heterogeneity and the stability of the results.

Results:

Fourteen population-based cohort studies (17 individual comparisons) involving 396,332 participants were identified. Meta-analysis showed that Met exposure was significantly associated with reduced risk of all subtypes of dementias [relative risk (RR) = 0.79, 95% CI = 0.68–0.91; p < 0.001]. Conversely, no significant reduction in risk was observed for those who received Met monotherapy at the onset of vascular dementia (VD), Parkinson’s disease (PD), and Alzheimer’s disease (AD). The effect was more prominent in patients who had long-term Met exposure (⩾4 years) (RR = 0.38, 95% CI = 0.32–0.46; p < 0.001), while no such significant effect was found with short-term Met exposure (1–2 years) (RR = 1.20, 95% CI = 0.87–1.66; p < 0.001). Moreover, no association was observed for Met exposure in participants of European descent (RR = 1.01, 95% CI = 0.66–1.54; p = 0.003) compared with those from other countries.

Conclusion:

Based on the evidence from population-based cohort studies, our findings suggest that the AMPK activator, Met, is a potential geroprotective agent for dementias, particularly among long-term Met users. Due to the significant heterogeneity among the included studies, we should interpret the results with caution.

AMPK Modulates the Metabolic Adaptation of C6 Glioma Cells in Glucose-Deprived Conditions without Affecting Glutamate Transport

Energy homeostasis in the central nervous system largely depends on astrocytes, which provide metabolic support and protection to neurons. Astrocytes also ensure the clearance of extracellular glutamate through high-affinity transporters, which indirectly consume ATP. Considering the role of the AMP-activated protein kinase (AMPK) in the control of cell metabolism, we have examined its implication in the adaptation of astrocyte functions in response to a metabolic stress triggered by glucose deprivation. We genetically modified the astrocyte-like C6 cell line to silence AMPK activity by overexpressing a dominant negative mutant of its catalytic subunit. Upon glucose deprivation, we found that C6 cells maintain stable ATP levels and glutamate uptake capacity, highlighting their resilience during metabolic stress. In the same conditions, cells with silenced AMPK activity showed a reduction in motility, metabolic activity, and ATP levels, indicating that their adaptation to stress is compromised. The rate of ATP production remained, however, unchanged by AMPK silencing, suggesting that AMPK mostly influences energy consumption during stress conditions in these cells. Neither AMPK modulation nor prolonged glucose deprivation impaired glutamate uptake. Together, these results indicate that AMPK contributes to the adaptation of astrocyte metabolism triggered by metabolic stress, but not to the regulation of glutamate transport.

Puerarin protects against sepsis-induced myocardial injury through AMPK-mediated ferroptosis signaling

Objective: Research suggests that Puerarin may protect against sepsis-induced myocardial damage. However, the mechanisms responsible for Puerarin’s cardioprotective effect remain largely unclear. In this study, our objective is to investigate the role of Puerarin-induced AMPK-mediated ferroptosis signaling in protecting myocardial injury.

Methods: 48 male Sprague-Dawley rats were randomly divided into four groups: control group, LPS group, LPS + Pue group, LPS + Pue + Era (Erastin, ferroptosis activator) group, or LPS + Pue + CC (compound C, AMPK inhibitor) group. During the experiment, cardiac systolic function indexes and myocardial histopathological changes were monitored. The serum levels of myocardial injury marker enzyme, inflammatory response related marker enzyme, and oxidative stress related-marker enzyme were measured with ELISA. Apoptotic cardiomyocytes, the iron content in myocardial tissue, apoptosis-related proteins, AMPK, and ferroptosis-related proteins were determined.

Results: Puerarin inhibited the myocardial injury induced by LPS. The cardioprotective effects of Puerarin decreased after adding ferroptosis-activating compound Erastin. The protein expression levels of GPX4 and ferritin were down-regulated, whereas ACSL4, TFR, and heart iron content were up-regulated in LPS + Pue + Era group compared with LPS+Pue group. A significant difference was identified between LPS + Pue + Era group and LPS + Pue group in P-AMPK and T-AMPK levels. Meanwhile, after providing CC, P-AMPK/T-AMPK was significantly reduced, the protein expression levels of GPX4 and ferritin were down-regulated. ACSL4, TFR, and the heart iron content were up-regulated in LPS + Pue + CC group compared to LPS + Pue group.

Conclusions: Puerarin protected against sepsis-induced myocardial injury, and AMPK-mediated ferroptosis signaling played a crucial role in its cardioprotective effect.

Chitosan oligosaccharide regulates AMPK and STAT1 pathways synergistically to mediate PD-L1 expression for cancer chemoimmunotherapy

After regular chemotherapy, the expression of programmed cell death ligand 1 (PD-L1) in almost all kinds of cancers is significantly increased, leading to reduced efficacy of T cell mediated immune killing in tumors. To solve this, a lot of PD-L1 antibodies were produced and used, but their high cost and serious toxic side effects still limit its usage. Recently, small molecule compounds that could effectively regulate PD-L1 expression possess the edges to solve the problems of PD-L1 antibodies. Chitosan oligosaccharide (COS), a biomaterial derived from the N-deacetylation product of chitin, has a broad spectrum of biological activities in treating tumors. However, the mechanism of its anti-cancer effect is still not well understood. Here, for the first time, we clearly identified that COS could inhibit the upregulated PD-L1 expression induced by interferon γ (IFN-γ) in various tumors via the AMPK activation and STAT1 inhibition. Besides, COS itself significantly restricted the growth of CT26 tumors by enhancing the T cell infiltration in tumors. Furthermore, we observed that combining COS with Gemcitabine (GEM), one of the typical chemotherapeutic drugs, leaded to a more remarkable tumor remission. Therefore, it was demonstrated that COS could be used as a useful way to improve the efficacy of existing chemotherapies by effective PD-L1 downregulation.

Promise of metformin for preventing age-related cognitive dysfunction

The expanded lifespan of people, while a positive advance, has also amplified the prevalence of age-related disorders, which include mild cognitive impairment, dementia, and Alzheimer's disease. Therefore, competent therapies that could improve the healthspan of people have great significance. Some of the dietary and pharmacological approaches that augment the lifespan could also preserve improved cognitive function in old age. Metformin, a drug widely used for treating diabetes, is one such candidate that could alleviate age-related cognitive dysfunction. However, the possible use of metformin to alleviate age-related cognitive dysfunction has met with conflicting results in human and animal studies. While most clinical studies have suggested the promise of metformin to maintain better cognitive function and reduce the risk for developing dementia and Alzheimer's disease in aged diabetic people, its efficacy in the nondiabetic population is still unclear. Moreover, a previous animal model study implied that metformin could adversely affect cognitive function in the aged. However, a recent animal study using multiple behavioral tests has reported that metformin treatment in late middle age improved cognitive function in old age. The study also revealed that cognition-enhancing effects of metformin in aged animals were associated with the activation of the energy regulator adenosine monophosphate-activated protein kinase, diminished neuroinflammation, inhibition of the mammalian target of rapamycin signaling, and augmented autophagy in the hippocampus. The proficiency of metformin to facilitate these favorable modifications in the aged hippocampus likely underlies its positive effect on cognitive function. Nonetheless, additional studies probing the outcomes of different doses and durations of metformin treatment at specific windows in the middle and old age across sex in nondiabetic and non-obese prototypes are required to substantiate the promise of metformin to maintain better cognitive function in old age.

HuR-Targeted Inhibition Impairs Th2 Proinflammatory Responses in Asthmatic CD4+ T Cells

RNA-binding protein HuR (ELAVL1) is a master regulator of gene expression in human pathophysiology. Its dysregulation plays an important role in many diseases. We hypothesized that HuR plays an important role in Th2 inflammation in asthma in both mouse and human. To address this, we used a model of airway inflammation in a T cell-specific knockout mouse model, distal lck-Cre HuR^fl/fl, as well as small molecule inhibitors in human peripheral blood-derived CD4⁺ T cells. Peripheral CD4⁺ T cells were isolated from 26 healthy control subjects and 45 asthmatics (36 type 2 high and 9 non-type 2 high, determined by blood eosinophil levels and fraction of exhaled NO). Our mouse data showed conditional ablation of HuR in T cell-abrogated Th2 differentiation, cytokine production, and lung inflammation. Studies using human T cells showed that HuR protein levels in CD4⁺ T cells were significantly higher in asthmatics compared with healthy control subjects. The expression and secretion of Th2 cytokines were significantly higher in asthmatics compared with control subjects. AMP-activated protein kinase activator treatment reduced the expression of several cytokines in both type 2 high and non-type 2 high asthma groups. However, the effects of CMLD-2 (a HuR-specific inhibitor) were more specific to endotype-defining cytokines in type 2 high asthmatics. Taken together, these data suggest that HuR plays a permissive role in both allergen and non-allergen-driven airway inflammation by regulating key genes, and that interfering with its function may be a novel method of asthma treatment.

Autophagy and apoptosis cascade: which is more prominent in neuronal death?

Autophagy and apoptosis are two crucial self-destructive processes that maintain cellular homeostasis, which are characterized by their morphology and regulated through signal transduction mechanisms. These pathways determine the fate of cellular organelle and protein involved in human health and disease such as neurodegeneration, cancer, and cardiovascular disease. Cell death pathways share common molecular mechanisms, such as mitochondrial dysfunction, oxidative stress, calcium ion concentration, reactive oxygen species, and endoplasmic reticulum stress. Some key signaling molecules such as p53 and VEGF mediated angiogenic pathway exhibit cellular and molecular responses resulting in the triggering of apoptotic and autophagic pathways. Herein, based on previous studies, we describe the intricate relation between cell death pathways through their common genes and the role of various stress-causing agents. Further, extensive research on autophagy and apoptotic machinery excavates the implementation of selective biomarkers, for instance, mTOR, Bcl-2, BH3 family members, caspases, AMPK, PI3K/Akt/GSK3β, and p38/JNK/MAPK, in the pathogenesis and progression of neurodegenerative diseases. This molecular phenomenon will lead to the discovery of possible therapeutic biomolecules as a pharmacological intervention that are involved in the modulation of apoptosis and autophagy pathways. Moreover, we describe the potential role of micro-RNAs, long non-coding RNAs, and biomolecules as therapeutic agents that regulate cell death machinery to treat neurodegenerative diseases. Mounting evidence demonstrated that under stress conditions, such as calcium efflux, endoplasmic reticulum stress, the ubiquitin-proteasome system, and oxidative stress intermediate molecules, namely p53 and VEGF, activate and cause cell death. Further, activation of p53 and VEGF cause alteration in gene expression and dysregulated signaling pathways through the involvement of signaling molecules, namely mTOR, Bcl-2, BH3, AMPK, MAPK, JNK, and PI3K/Akt, and caspases. Alteration in gene expression and signaling cascades cause neurotoxicity and misfolded protein aggregates, which are characteristics features of neurodegenerative diseases. Excessive neurotoxicity and misfolded protein aggregates lead to neuronal cell death by activating death pathways like autophagy and apoptosis. However, autophagy has a dual role in the apoptosis pathways, i.e., activation and inhibition of the apoptosis signaling. Further, micro-RNAs and LncRNAs act as pharmacological regulators of autophagy and apoptosis cascade, whereas, natural compounds and chemical compounds act as pharmacological inhibitors that rescue neuronal cell death through inhibition of apoptosis and autophagic cell death.

The Signaling Pathways Regulating NLRP3 Inflammasome Activation

The NLRP3 inflammasome is a multi-molecular complex that acts as a molecular platform to mediate caspase-1 activation, leading to IL-1β/IL-18 maturation and release in cells stimulated by various pathogen-associated molecular patterns (PAMPs) or damage-associated molecular patterns (DAMPs). This inflammasome plays an important role in the innate immunity as its activation can further promote the occurrence of inflammation, enhance the ability of host to remove pathogens, and thus facilitate the repair of injured tissues. But if the inflammasome activation is dysregulated, it will cause the development of various inflammatory diseases and metabolic disorders. Therefore, under normal conditions, the activation of inflammasome is tightly regulated by various positive and negative signaling pathways to respond to the stimuli without damaging the host itself while maintaining homeostasis. In this review, we summarize recent advances in the major signaling pathways (including TLRs, MAPK, mTOR, autophagy, PKA, AMPK, and IFNR) that regulate NLRP3 inflammasome activation, providing a brief view of the molecular network that regulates this inflammasome as a theoretical basis for therapeutic intervention of NLRP3 dysregulation-related diseases.

Transcriptome and metabolome analysis of crGART, a novel cell model of de novo purine synthesis deficiency: Alterations in CD36 expression and activity

In humans, GART [phosphoribosylglycinamide formyltransferase (EC 2.1.2.2) / phosphoribosylglycinamide synthetase (EC 6.3.4.13) / phosphoribosylaminoimidazole synthetase (EC 6.3.3.1)] is a trifunctional protein which catalyzes the second, third, and fifth reactions of the ten step de novo purine synthesis (DNPS) pathway. The second step of DNPS is conversion of phosphoribosylamine (5-PRA) to glycineamide ribonucleotide (GAR). 5-PRA is extremely unstable under physiological conditions and is unlikely to accumulate in the absence of GART activity. Recently, a HeLa cell line null mutant for GART was constructed via CRISPR-Cas9 mutagenesis. This cell line, crGART, is an important cellular model of DNPS inactivation that does not accumulate DNPS pathway intermediates. In the current study, we characterized the crGART versus HeLa transcriptomes in purine-supplemented and purine-depleted growth conditions. We observed multiple transcriptome changes and discuss pathways and ontologies particularly relevant to Alzheimer disease and Down syndrome. We selected the Cluster of Differentiation (CD36) gene for initial analysis based on its elevated expression in crGART versus HeLa as well as its high basal expression, high log2 value, and minimal P-value.

Targeting Future Pandemics, a Case for De Novo Purine Synthesis and Basic Research

We are currently experiencing a deadly novel viral pandemic with no efficacious, readily available anti-viral therapies to SARS-CoV-2. Viruses will hijack host cellular machinery, including metabolic processes. Here, I provide theory and evidence for targeting the host de novo purine synthetic pathway for broad spectrum anti-viral drug development as well as the pursuit of basic science to mitigate the risks of future novel viral outbreaks.

The second phase of brain trauma can be controlled by nutraceuticals that suppress DAMP-mediated microglial activation

INTRODUCTION

A delayed second wave of brain trauma is mediated in large part by microglia that are activated to a pro-inflammatory M1 phenotype by DAMP proteins released by dying neurons. These microglia can promote apoptosis or necrosis in neighboring neurons by producing a range of pro-inflammatory cytokines and the deadly oxidant peroxynitrite. This second wave could therefore be mitigated with agents that blunt the post-traumatic M1 activation of microglia and that preferentially promote a pro-healing M2 phenotype.

AREAS COVERED

The literature on nutraceuticals that might have clinical potential in this regard.

EXPERT OPINION

The chief signaling pathway whereby DAMPs promote M1 microglial activation involves activation of toll-like receptor 4 (TLR4), NADPH oxidase, NF-kappaB, and the stress activated kinases JNK and p38. The green tea catechin EGCG can suppress TLR4 expression. Phycocyanobilin can inhibit NOX2-dependent NADPH oxidase, ferulate and melatonin can oppose pro-inflammatory signal modulation by NADPH oxidase-derived oxidants. Long-chain omega-3 fatty acids, the soy isoflavone genistein, the AMPK activator berberine, glucosamine, and ketone bodies can down-regulate NF-kappaB activation. Vitamin D activity can oppose JNK/p38 activation. A sophisticated program of nutraceutical supplementation may have important potential for mitigating the second phase of neuronal death and aiding subsequent healing.

NQO1 mediates the anti-inflammatory effects of nootkatone in lipopolysaccharide-induced neuroinflammation by modulating the AMPK signaling pathway

Neuroinflammation and oxidative stress play key roles in the progression of neurodegenerative diseases. Thus, the use of potent anti-inflammatory/antioxidant agents has been suggested as a promising therapeutic strategy for neurodegenerative diseases. In the present study, we investigated the anti-inflammatory and antioxidant effects of nootkatone (NKT), a sesquiterpenoid compound isolated from grapefruit, in in vitro and in vivo models of neuroinflammation. In lipopolysaccharide (LPS)-stimulated BV2 microglial cells, NKT inhibited the expression of iNOS, COX-2, and pro-inflammatory cytokines, and increased the expression of the anti-inflammatory cytokine, IL-10. In addition, NKT inhibited reactive oxygen species (ROS) production and upregulated the expression of antioxidant enzymes, such as NQO1 and HO-1. Molecular mechanistic studies showed that NKT inhibited Akt, p38 MAPK, and NF-κB activities, while increasing AMPK, PKA/CREB, and Nrf2/ARE signaling in LPS-stimulated BV2 cells. Since NKT dramatically increased NQO1 expression, we investigated the role of this enzyme using pharmacological inhibition or knockdown experiments. Treatment of BV2 cells with the NQO1-specific inhibitor, dicoumarol, or with NQO1 siRNA significantly blocked NKT-mediated inhibition of NO, ROS, TNF-α, IL-1β, and upregulation of IL-10. Furthermore, NQO1 inhibition reversed the effects of NKT on pro- and anti-inflammatory signaling molecules. Intriguingly, we found that the AMPK inhibitor, compound C, mimicked the effects of dicoumarol, suggesting the presence of a crosstalk between NQO1 and AMPK. Finally, we demonstrated that NKT inhibited microglial activation, lipid peroxidation, and the expression of pro-inflammatory markers in the brains of LPS-injected mice, which was also reversed by dicoumarol. These data collectively suggest that NQO1 plays a critical role in mediating the anti-inflammatory and antioxidant effects of NKT in LPS-induced neuroinflammation by modulating AMPK and its downstream signaling pathways.

Immunotherapy Targeting Myeloid-Derived Suppressor Cells (MDSCs) in Tumor Microenvironment

Myeloid-derived suppressor cells (MDSCs) are a heterogeneous population of immature myeloid cells that accumulate in tumor-bearing hosts to reduce T cells activity and promote tumor immune escape in the tumor microenvironment (TME). The immune system in the TME can be stimulated to elicit an anti-tumor immune response through immunotherapy. The main theory of immunotherapy resides on the plasticity of the immune system and its capacity to be re-educated into a potent anti-tumor response. Thus, MDSCs within the TME became one of the major targets to improve the efficacy of tumor immunotherapy, and therapeutic strategies for tumor MDSCs were developed in the last few years. In the article, we analyzed the function of tumor MDSCs and the regulatory mechanisms of agents targeting MDSCs in tumor immunotherapy, and reviewed their therapeutic effects in MDSCs within the TME. Those data focused on discussing how to promote the differentiation and maturation of MDSCs, reduce the accumulation and expansion of MDSCs, and inhibit the function, migration and recruitment of MDSCs, further preventing the growth, invasion and metastasis of tumor. Those investigations may provide new directions for cancer therapy.

Diosmetin Ameliorates Nonalcoholic Steatohepatitis through Modulating Lipogenesis and Inflammatory Response in a STAT1/CXCL10-Dependent Manner

Nonalcoholic steatohepatitis (NASH) is an inflammatory lipotoxic disorder characterized by lipid accumulation and inflammation. Diosmetin (Dios), a flavonoid, has an active effect against nonalcoholic fatty liver disease, whereas its effect on NASH remains elusive. To investigate the effects of Dios on lipogenesis and inflammatory response and explore the molecular mechanisms of Dios on NASH, mice induced by high-fat diet (HFD), HepG2 cells stimulated by palmitic acid (PA), transcriptome sequencing, and molecular biological experiments were used. We show, by pathological analysis (HE, Oli Red O, and Masson staining) and biochemical parameters (TC, TG, LDL-C, ALT, and AST), Dios alleviated liver lipid accumulation and inflammatory injury. According to liver RNA-Seq analysis, CXCL10 and STAT1 were assumed to be the key target genes of Dios on NASH. Significantly, Dios regulated STAT1/CXCL10 signal pathway and further attenuated NASH via regulating the expression of LXRα/β, SREBP-1c, CHREBP, and NF-κB. In conclusion, Dios is proposed to alleviate NASH through suppression of lipogenesis and inflammatory response via a STAT1/CXCL10-dependent pathway.

Tumor inhibition or tumor promotion? The duplicity of CXCR3 in cancer

Tumor tissue includes cancer cells and normal stromal cells such as vascular endothelial cells, connective tissue cells (cancer associated fibroblast, mesenchymal stem cell), and immune cells (tumor-infiltrating lymphocytes or TIL, dendritic cells, eosinophils, basophils, mast cells, tumor-associated macrophages or TAM, myeloid-derived suppressor cells or MDSC). Anti-tumor activity is mainly mediated by infiltration of NK cells, Th1 and CD8⁺ T cells, and correlates with expression of NK cell and T cell attracting chemokines. Nevertheless, cancer cells hijack tissue homeostasis through secretion of cytokines and chemokines that mediate not only the induction of an inflamed status that supports cancer cell survival and growth, but also the recruitment and/or activation of immune suppressive cells. CXCL9, CXCL10, and CXCL11 are known for their tumor-inhibiting properties, but their overexpression in several hematologic and solid tumors correlates with disease severity, suggesting a role in tumor promotion. The dichotomous nature of CXCR3 ligands activity mainly depends on several molecular mechanisms induced by cancer cells themselves able to divert immune responses and to alter the whole local environment. A deep understanding of the nature of such phenomenon may provide a rationale to build up a CXCR3/ligand axis targeting strategy. In this review, we will discuss the role of CXCR3 in cancer progression and in regulation of anti-tumor immune response and immunotherapy.

The CRISPR-Cas9 crATIC HeLa transcriptome: Characterization of a novel cellular model of ATIC deficiency and ZMP accumulation

In de novo purine biosynthesis (DNPS), 5-aminoimidazole-4-carboxamide ribonucleotide formyltransferase (EC 2.1.2.3)/inosine monophosphate cyclohydrolase (EC 3.5.4.10) (ATIC) catalyzes the last two reactions of the pathway: conversion of 5-aminoimidazole-4-carboxamide ribonucleotide [aka Z-nucleotide monophosphate (ZMP)] to 5-formamido-4-imidazolecarboxamide ribonucleotide (FAICAR) then to inosine monophosphate (IMP). Mutations in ATIC cause an untreatable and devastating inborn error of metabolism in humans. ZMP is an adenosine monophosphate (AMP) mimetic and a known activator of AMP-activated protein kinase (AMPK). Recently, a HeLa cell line null mutant for ATIC was constructed via CRISPR-Cas9 mutagenesis. This mutant, crATIC, accumulates ZMP during purine starvation. Given that the mutant can accumulate ZMP in the absence of treatment with exogenous compounds, crATIC is likely an important cellular model of DNPS inactivation and ZMP accumulation. In the current study, we characterize the crATIC transcriptome versus the HeLa transcriptome in purine-supplemented and purine-depleted growth conditions. We report and discuss transcriptome changes with particular relevance to Alzheimer's disease and in genes relevant to lipid and fatty acid synthesis, neurodevelopment, embryogenesis, cell cycle maintenance and progression, extracellular matrix, immune function, TGFβ and other cellular processes.

Mitigation of Microglia-mediated Acute Neuroinflammation and Tissue Damage by Heme Oxygenase 1 in a Rat Spinal Cord Injury Model

Acute neuroinflammation is the major detrimental factor that causes secondary tissue damage after spinal cord injury (SCI). Curbing neuroinflammation would reduce the neuronal death and benefit functional recovery. In the current study, we used a HO-1-encoding lentivirus to transduce microglia, and adoptively transferred these microglia into injured rat spinal cords. Lentivirus-induced overexpression of exogenous HO-1 significantly inhibited microglia-mediated inflammatory response after SCI, as demonstrated by lower expression of pro-inflammatory mediators in transferred microglia. In addition, the overall post-SCI neuroinflammation was also suppressed by HO-1-overexpressing microglia, as indicated by less leukocyte infiltration and lower pro-inflammatory cytokine production in the spinal cord. Consistently, the tissue damage and neuronal apoptosis were decreased in injured spinal cords, while the locomotor function was moderately improved. We further identified that adenosine 5'-monophosphate-activated protein kinase (AMPK) signaling was involved in the regulatory effect of HO-1 on microglia, because HO-1 overexpression increased the activating phosphorylation of AMPKα. Moreover, the AMPK inhibitor compound C diminished the anti-inflammatory effect of HO-1 in lipopolysaccharide-stimulated microglia in vitro. Taken together, we proved that microglial HO-1 reduced acute post-SCI neuroinflammation. Our study might provide a promising therapeutic approach to benefit SCI recovery.

Downregulation of Cancer-Associated lncRNAs in Peripheral Blood of Multiple Sclerosis Patients

Recent studies have shown contribution of long non-coding RNAs (lncRNAs) in the pathogenesis of immune-related disorders including multiple sclerosis (MS). Based on the role of these transcripts in the regulation of immune response, peripheral levels of lncRNAs can reflect the level of immune activation. In the present study, we quantified expression of four lncRNAs namely SPRY4-IT1, HOXA-AS2, LINC-ROR, and MEG3 in venous blood of MS patients and controls using quantitative real-time PCR method. Relative expressions of SPRY4-IT1, HOXA-AS2, LINC-ROR, and MEG3 were significantly lower in female MS patients compared with female healthy subjects. For MEG3, this pattern of expression was also observed in male subjects. However, for other lncRNAs, no significant difference was detected between male patients and male controls. Expression of HOXA-AS2 was correlated with progression index (r = 0.36, P < 0.001). Besides, there was a significant correlation between expression of this lncRNA and expression of LINC-ROR in MS patients (r = 0.44, P < 0.0001). There was no other correlation between expression of lncRNAs and clinical data in MS patients. In control group, expressions of none of lncRNAs were correlated with age of persons. Notably, significant correlations were demonstrated between expression levels of all lncRNAs in healthy subjects with r values ranging from 0.23 to 0.42. The current investigation shows dysregulation of lncRNAs in MS patients in a sex-specific manner and warrants further studies to unravel the clinical and therapeutic implications of such dysregulation.

The metabolic response to inflammation in astrocytes is regulated by nuclear factor-kappa B signaling

Inflammation and metabolism are intrinsically linked with inflammatory stimuli inducing metabolic changes in cells and, in turn, metabolic capacity determining cellular inflammatory responses. Although well characterized in peripheral immune cells there is comparatively less known about these "immunometabolic" responses in astrocytes. In this study, we tested the hypothesis that the astrocytic inflammatory response driven by nuclear factor-kappa B (NF-κB) signaling is dependent on glycolytic metabolism. Using mouse primary cortical astrocyte cultures, we assessed changes in cellular metabolism after exposure to lipopolysaccharide (LPS), with cytokine ELISAs and immunoblotting being used to measure inflammatory responses. Results indicate temporally distinct metabolic adaptations to pro-inflammatory stimulation in astrocytes: 3 hr LPS treatment increased glycolysis but did not alter mitochondrial metabolism, while following 24 hr of LPS treatment we observed increased oxidative phosphorylation, and decreased glycolytic capacity and glucose uptake, partly due to reduced glucose transporter 1 expression. Inhibition of NF-κB signaling with the IKK-beta inhibitor TPCA-1 prevented the LPS induced changes to glycolysis and oxidative phosphorylation. Furthermore, TPCA-1 treatment altered both glycolysis and oxidative phosphorylation independently from inflammatory stimulation, indicating a role for NF-κB signaling in regulation of basal metabolism in astrocytes. Inhibition of glycolysis with 2-deoxyglucose significantly attenuated LPS-induced cytokine release and NF-κB phosphorylation, indicating that intact glycolysis is required for the full inflammatory response to LPS. Together our data indicate that astrocytes display immunometabolic responses to acute LPS stimulation which may represent a potential therapeutic target for neuroinflammatory disorders.

SIRT1 Mediates Melatonin's Effects on Microglial Activation in Hypoxia: In Vitro and In Vivo Evidence

Melatonin exerts direct neuroprotection against cerebral hypoxic damage, but the mechanisms of its action on microglia have been less characterized. Using both in vitro and in vivo models of hypoxia, we here focused on the role played by silent mating type information regulation 2 homolog 1 (SIRT1) in melatonin's effects on microglia. Viability of rat primary microglia or microglial BV2 cells and SH-SY5Y neurons was significantly reduced after chemical hypoxia with CoCl₂ (250 μM for 24 h). Melatonin (1 μM) significantly attenuated CoCl₂ toxicity on microglia, an effect prevented by selective SIRT1 inhibitor EX527 (5 μM) and AMP-activated protein kinase (AMPK) inhibitor BML-275 (2 μM). CoCl₂ did not modify SIRT1 expression, but prevented nuclear localization, while melatonin appeared to restore it. CoCl₂ induced nuclear localization of hypoxia-inducible factor-1α (HIF-1α) and nuclear factor-kappa B (NF-kB), an effect contrasted by melatonin in an EX527-dependent fashion. Treatment of microglia with melatonin attenuated potentiation of neurotoxicity. Common carotid occlusion was performed in p7 rats, followed by intraperitoneal injection of melatonin (10 mg/kg). After 24 h, the number of Iba1+ microglia in the hippocampus of hypoxic rats was significantly increased, an effect not prevented by melatonin. At this time, SIRT1 was only detectable in the amoeboid, Iba1+ microglial population selectively localized in the corpus callosum. In these cells, nuclear localization of SIRT1 was significantly lower in hypoxic animals, an effect prevented by melatonin. NF-kB showed an opposite expression pattern, where nuclear localization in Iba1+ cells was significantly higher in hypoxic, but not in melatonin-treated animals. Our findings provide new evidence for a direct effect of melatonin on hypoxic microglia through SIRT1, which appears as a potential pharmacological target against hypoxic-derived neuronal damage.

Metformin accelerates myelin recovery and ameliorates behavioral deficits in the animal model of multiple sclerosis via adjustment of AMPK/Nrf2/mTOR signaling and maintenance of endogenous oligodendrogenesis during brain self-repairing period

BACKGROUND

Multiple sclerosis (MS) is a devastating autoimmune disorder characterized by oligodendrocytes (OLGs) loss and demyelination. In this study, we have examined the effects of metformin (MET) on the oligodendrogenesis, redox signaling, apoptosis, and glial responses during a self-repairing period (1-week) in the animal model of MS.

METHODS

For induction of demyelination, C57BL/6 J mice were fed a 0.2% cuprizone (CPZ) for 5 weeks. Thereafter, CPZ was removed for 1-week and molecular and behavioral changes were monitored in the presence or absence of MET (50 mg/kg body weight/day).

RESULTS

MET remarkably increased the localization of precursor OLGs (NG2⁺/O4⁺ cells) and subsequently the renewal of mature OLGs (MOG⁺ cells) in the corpus callosum via AMPK/mammalian target of rapamycin (mTOR) pathway. Moreover, we observed a significant elevation in the antioxidant responses, especially in mature OLGs (MOG⁺/nuclear factor erythroid 2-related factor 2 (Nrf2⁺) cells) after MET intervention. MET also reduced brain apoptosis markers and lessened motor dysfunction in the open-field test. While MET was unable to decrease active astrogliosis (GFAP mRNA), it reduced microgliosis by down-regulation of Mac-3 mRNA a marker of pro-inflammatory microglia/macrophages. Molecular modeling studies, likewise, confirmed that MET exerts its effects via direct interaction with AMPK.

CONCLUSIONS

Altogether, our study reveals that MET effectively induces lesion reduction and elevated molecular processes that support myelin recovery via direct activation of AMPK and indirect regulation of AMPK/Nrf2/mTOR pathway in OLGs. These findings facilitate the development of new therapeutic strategies based on AMPK activation for MS in the near future.

Janus Kinase 1 Is Required for Transcriptional Reprograming of Murine Astrocytes in Response to Endoplasmic Reticulum Stress

Neurodegenerative diseases are associated with the accumulation of misfolded proteins in the endoplasmic reticulum (ER), leading to ER stress. To adapt, cells initiate the unfolded protein response (UPR). However, severe or unresolved UPR activation leads to cell death and inflammation. The UPR is initiated, in part, by the trans-ER membrane kinase PKR-like ER kinase (PERK). Recent evidence indicates ER stress and inflammation are linked, and we have shown that this involves PERK-dependent signaling via Janus Kinase (JAK) 1. This signaling provokes the production of soluble inflammatory mediators such as interleukin-6 (IL-6) and chemokine C-C motif ligand 2 (CCL2). We, therefore, hypothesized that JAK1 may control widespread transcriptional changes in response to ER stress. Here, using RNA sequencing of primary murine astrocytes, we demonstrate that JAK1 regulates approximately 10% of ER stress-induced gene expression and is required for a subset of PERK-dependent genes. Additionally, ER stress synergizes with tumor necrosis factor-α (TNF-α) to drive inflammatory gene expression in a JAK1-dependent fashion. We identified that JAK1 contributes to activating transcription factor (ATF) 4-dependent gene expression, including expression of the genes growth arrest and DNA damage (GADD) 45α and tribbles (TRIB) 3 that have not previously been associated with JAK signaling. While these genes are JAK1 dependent in response to ER stress, expression of GADD45α and TRIB3 are not induced by the JAK1-activating cytokine, oncostatin M (OSM). Transcriptomic analysis revealed that JAK1 drives distinct transcriptional programs in response to OSM stimulation versus ER stress. Interestingly, JAK1-dependent genes induced by ER stress in an ATF4-dependent mechanism were unaffected by small molecule inhibition of JAK1, suggesting that, in response to UPR activation, JAK1 initiates gene expression using non-canonical mechanisms. Overall, we have identified that JAK1 is a major regulator of ER stress-induced gene expression.

IFNγ: signalling, epigenetics and roles in immunity, metabolism, disease and cancer immunotherapy

IFNγ is a cytokine with important roles in tissue homeostasis, immune and inflammatory responses and tumour immunosurveillance. Signalling by the IFNγ receptor activates the Janus kinase (JAK)-signal transducer and activator of transcription 1 (STAT1) pathway to induce the expression of classical interferon-stimulated genes that have key immune effector functions. This Review focuses on recent advances in our understanding of the transcriptional, chromatin-based and metabolic mechanisms that underlie IFNγ-mediated polarization of macrophages to an 'M1-like' state, which is characterized by increased pro-inflammatory activity and macrophage resistance to tolerogenic and anti-inflammatory factors. In addition, I describe the newly discovered effects of IFNγ on other leukocytes, vascular cells, adipose tissue cells, neurons and tumour cells that have important implications for autoimmunity, metabolic diseases, atherosclerosis, neurological diseases and immune checkpoint blockade cancer therapy.

Distinct Protein Expression Networks are Activated in Microglia Cells after Stimulation with IFN-γ and IL-4

Microglia cells are the primary immune population of the central nervous system with a role in the regulation of several physiological and pathological conditions. Upon appropriate stimulation, microglia cells can be polarized in a pro-inflammatory M1-like or anti-inflammatory M2-like status. Biological processes and pathways engaged in microglia polarization are starting to be elucidated. To help clarify this, we used a liquid chromatography-mass spectrometry (LC-MS/MS) label free approach to characterize the proteomic profile of human microglia cell line (CHME-5) stimulated with gamma-interferon (IFN-γ) and interleukin-4 (IL-4) to induce a M1 or M2 phenotype, respectively. Outside the classical M1/M2 polarization markers, the M1 status appears to center around the activation of a classical inflammatory response and through the activation of multiple signaling pathways. M2 polarization resulted in a different pattern of protein modulation related to RNA and cellular metabolic processes. Together, our findings provide information regarding the protein changes specific to M1 and M2 activation states, and potentially link the polarization of microglia cells to the acquisition of a specific proteomic profile.

AMPK activation inhibits the functions of myeloid-derived suppressor cells (MDSC): impact on cancer and aging

AMP-activated protein kinase (AMPK) has a crucial role not only in the regulation of tissue energy metabolism but it can also control immune responses through its cooperation with immune signaling pathways, thus affecting immunometabolism and the functions of immune cells. It is known that AMPK signaling inhibits the activity of the NF-κB system and thus suppresses pro-inflammatory responses. Interestingly, AMPK activation can inhibit several major immune signaling pathways, e.g., the JAK-STAT, NF-κB, C/EBPβ, CHOP, and HIF-1α pathways, which induce the expansion and activation of myeloid-derived suppressor cells (MDSC). MDSCs induce an immunosuppressive microenvironment in tumors and thus allow the escape of tumor cells from immune surveillance. Chronic inflammation has a key role in the expansion and activation of MDSCs in both tumors and inflammatory disorders. The numbers of MDSCs also significantly increase during the aging process concurrently with the immunosenescence associated with chronic low-grade inflammation. Increased fatty acid oxidation and lactate produced by aerobic glycolysis are important immunometabolic enhancers of MDSC functions. However, it seems that AMPK signaling regulates the functions of MDSCs in a context-dependent manner. Currently, the activators of AMPK signaling are promising drug candidates for cancer therapy and possibly for the extension of healthspan and lifespan. We will describe in detail the AMPK-mediated regulation of the signaling pathways controlling the expansion and activation of immunosuppressive MDSCs. We will propose that the beneficial effects mediated by AMPK activation, e.g., in cancers and the aging process, could be induced by the inhibition of MDSC functions.

Low-Dose Tacrolimus Prevents Dysregulated Peri-Conceptional Ovarian and Systemic Immune Cellular Homeostasis in Subjects with PCOS

Polycystic ovary syndrome (PCOS) is characterized by failure of ovulation and is associated with obesity and chronic inflammation. Recent evidence suggests that anomalous activation of ovarian macrophages and numerical and functional deficits in the Th17 (CD4+IL17A+) and the CD4+CD25+CD127^low Tregs plays crucial role in PCOS. We have shown that the pre-pregnancy use of tacrolimus prevents adverse reproductive outcomes in a mouse model of PCOS. Here we used the HFD-NONcNZO mice to test a hypothesized beneficial use of tacrolimus relative to metformin in favorably influencing the ovarian and systemic immune milieux conducive to gestational success in subjects with PCOS. Compared to normative controls, our data revealed an aberrant peri-conceptional suppression of the CD4⁺CD25⁺CD127^low Tregs together with an overexpression of the Th17 T cells and lack of coordinated activation of ovarian macrophages in untreated HFD-dNONcNZO mice. Significant variances in treatment outcomes favoured the use of tacrolimus over metformin in treated mice. Consistent with the human fertility studies, this investigation reveals a beneficial systemic use of tacrolimus (0.1 mg/kg) in promoting early pregnancy in individuals with PCOS and suggests the need for further research into the selective inhibition of IL17A as a plausibly alternative immunotherapeutic approach in the clinical management of infertile individuals with PCOS.

Effect of Shenfu injection on lipopolysaccharide (LPS)-induced septic shock in rabbits

ETHNOPHARMACOLOGICAL RELEVANCE

Shenfu injection is a popular Chinese herbal formula that has been widely used in the treatment of shock in China.

AIM OF THE STUDY

To investigate the effect of Shenfu injection on lipopolysaccharide (LPS)-induced septic shock in rabbits.

MATERIALS AND METHODS

We established a septic shock model in rabbits by administering an intravenous injection of 0.6 mg/kg LPS to anesthetized rabbit, and 15 min after LPS challenge, the rabbits were intravenously administered the Shenfu injection. In these in vivo experiments, the jugular vein of the rabbits was cannulated for LPS and drug administration, and the right common carotid artery was cannulated to record the mean arterial pressure (MAP) over a 6-h period. In addition, various serum biochemical parameters, including lactate dehydrogenase (LDH), aspartate aminotransferase (AST), glutamate transaminase (ALT), creatinine (Cre), and urea nitrogen (Urea), were measured at 0, 3, and 6 h. Serum LPS levels at 6 h were determined by the test kit. And histological changes in the heart, liver and kidney tissues were observed by HE staining. Furthermore, some related small molecules in the heart tissues were detected by MALDI-TOF-MSI.

RESULTS

We found that Shenfu injection can increase the MAP, decrease the serum LPS, LDH and AST levels, and improve the tissue morphology of the heart, liver and kidney in rabbits with LPS-induced septic shock. In addition, Shenfu injection can increase the contents of ATP and taurine while reducing the content of AMP in the heart tissue during septic shock.

CONCLUSIONS

These results indicate that Shenfu injection exerts a protective effect on LPS-induced septic shock in rabbits.

Anti-inflammatory and antioxidant mechanisms of urolithin B in activated microglia

BACKGROUND

Urolithin B is one of the gut microbial metabolites of ellagitannins and is found in diverse plant foods, including pomegranates, berries, walnuts, tropical fruits, and medicinal herbs. Although a number of biological activities of urolithin B have been reported, the anti-inflammatory and antioxidant effects of urolithin B in neuroinflammation have not been clearly demonstrated.

PURPOSE

The present study aimed to investigate the anti-inflammatory and antioxidant effects of urolithin B in activated microglia and define its underlying molecular mechanisms.

STUDY DESIGN

The effects of urolithin B on the expression of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), and cytokines were examined in BV2 microglial cells using enzyme-linked immunosorbent assay (ELISA), reverse transcription polymerase chain reaction (RT-PCR), and Western blot analysis. Microglial activation in the lipopolysaccharide (LPS)-injected mouse brain was assessed using immunohistochemistry. The detailed molecular mechanisms underlying the anti-inflammatory and antioxidant effects of urolithin B were analyzed using an electrophoretic mobility shift assay, reporter gene assay, Western blot, and RT-PCR.

RESULTS

Urolithin B inhibited the production of NO and pro-inflammatory cytokines, while increased anti-inflammatory cytokine IL-10 in LPS-stimulated BV2 microglial cells. In addition, urolithin B inhibited NO, TNF-α, and IL-6 production in lipoteichoic acid (LTA) or polyinosinic-polycytidylic acid (poly(I:C))-stimulated BV2 cells, suggesting that the anti-inflammatory effect of urolithin B is not confined to LPS stimulation. Urolithin B also showed an antioxidant effect by reducing intracellular reactive oxygen species (ROS) production and NADPH oxidase subunit expression, and by upregulating the antioxidant hemeoxygenase-1 expression via Nrf2/ARE signaling. More detailed mechanistic studies showed that urolithin B inhibited NF-κB activity by reducing the phosphorylation and degradation of IκBα. In addition, urolithin B suppressed the phosphorylation of JNK, ERK, and Akt, and enhanced the phosphorylation of AMPK, which is associated with anti-inflammatory and antioxidant processes. Finally, we demonstrated that urolithin B suppressed microglia activation in LPS-injected mouse brains.

CONCLUSIONS

The strong anti-inflammatory and antioxidant effects of urolithin B may provide therapeutic potential for neuroinflammatory disorders that are associated with oxidative stress and microglial activation.

Metabolic Checkpoints in Differentiation of Helper T Cells in Tissue Inflammation

Naïve CD4⁺ T cell differentiate into effector and regulatory subsets of helper T (Th) cells in various pathophysiological conditions and modulate tissue inflammation in autoimmune diseases. While cytokines play a key role in determining the fate of Th cells differentiation, metabolites, and metabolic pathways profoundly influence Th cells fate and their functions. Emerging literature suggests that interplay between metabolic pathways and cytokines potentiates T cell differentiation and functions in tissue inflammation in autoimmune diseases. Metabolic pathways, which are essential for the differentiation and functions of Th cell subsets, are regulated by cytokines, nutrients, growth factors, local oxygen levels, co-activation receptors, and metabolites. Dysregulation of metabolic pathways not only alters metabolic regulators in Th cells but also affect the outcome of tissue inflammation in autoimmune and allergic diseases. Understanding the modulation of metabolic pathways during T cells differentiation may potentially lead to a therapeutic strategy for immune-modulation of autoimmune and allergic diseases. In this review, we summarize the role of metabolic checkpoints and their crosstalk with different master transcription factors and signaling molecules in differentiation and function of Th subsets, which may potentially unravel novel therapeutic interventions for tissue inflammation and autoimmune disorders.

Dihydromyricetin Inhibits Lead-Induced Cognitive Impairments and Inflammation by the Adenosine 5'-Monophosphate-Activated Protein Kinase Pathway in Mice

Dihydromyricetin (DHM), a natural flavonoid derived from the medicinal and edible plant Ampelopsis grossedentata, exhibits antioxidant, antiapoptosis, antitumor, and anti-inflammatory bioactivities. This study evaluated the effects of DHM on Pb-induced neurotoxicity and explored the underlying mechanisms. DHM significantly ameliorated behavioral impairments of Pb-induced mice. It decreased the levels of lipid peroxidation and protein carbonyl and increased the activities of superoxide dismutase and catalase in the brains. DHM suppressed Pb-induced apoptosis, as indicated by the decreased levels of Bax and cleaved caspase-3. DHM also decreased inflammatory cytokines in the brains of Pb-treated mice. DHM decreased amyloid-beta (Aβ) level and nuclear factor-κB nuclear translocation. Moreover, DHM induced the adenosine 5'-monophosphate-activated protein kinase (AMPK) phosphorylation and inhibited the activation of p38, Toll-like receptor 4, myeloid differentiation factor 88, and glycogen synthase kinase-3. Collectively, this is the first report indicating that DHM could improve Pb-induced cognitive functional impairment by preventing oxidative stress, apoptosis, and inflammation and that the protective effect was mediated partly through the AMPK pathway.

The Therapeutic Potential of Metformin in Neurodegenerative Diseases

The search for treatments for neurodegenerative diseases is a major concern in light of today's aging population and an increasing burden on individuals, families, and society. Although great advances have been made in the last decades to understand the underlying genetic and biological cause of these diseases, only some symptomatic treatments are available. Metformin has long since been used to treat Type 2 Diabetes and has been shown to be beneficial in several other conditions. Metformin is well-tested in vitro and in vivo and an approved compound that targets diverse pathways including mitochondrial energy production and insulin signaling. There is growing evidence for the benefits of metformin to counteract age-related diseases such as cancer, cardiovascular disease, and neurodegenerative diseases. We will discuss evidence showing that certain neurodegenerative diseases and diabetes are explicitly linked and that metformin along with other diabetes drugs can reduce neurological symptoms in some patients and reduce disease phenotypes in animal and cell models. An interesting therapeutic factor might be how metformin is able to balance survival and death signaling in cells through pathways that are commonly associated with neurodegenerative diseases. In healthy neurons, these overarching signals keep energy metabolism, oxidative stress, and proteostasis in check, avoiding the dysfunction and neuronal death that defines neurodegenerative disease. We will discuss the biological mechanisms involved and the relevance of neuronal vulnerability and potential difficulties for future trials and development of therapies.

The Therapeutic Potential of Metformin in Neurodegenerative Diseases

The search for treatments for neurodegenerative diseases is a major concern in light of today's aging population and an increasing burden on individuals, families, and society. Although great advances have been made in the last decades to understand the underlying genetic and biological cause of these diseases, only some symptomatic treatments are available. Metformin has long since been used to treat Type 2 Diabetes and has been shown to be beneficial in several other conditions. Metformin is well-tested in vitro and in vivo and an approved compound that targets diverse pathways including mitochondrial energy production and insulin signaling. There is growing evidence for the benefits of metformin to counteract age-related diseases such as cancer, cardiovascular disease, and neurodegenerative diseases. We will discuss evidence showing that certain neurodegenerative diseases and diabetes are explicitly linked and that metformin along with other diabetes drugs can reduce neurological symptoms in some patients and reduce disease phenotypes in animal and cell models. An interesting therapeutic factor might be how metformin is able to balance survival and death signaling in cells through pathways that are commonly associated with neurodegenerative diseases. In healthy neurons, these overarching signals keep energy metabolism, oxidative stress, and proteostasis in check, avoiding the dysfunction and neuronal death that defines neurodegenerative disease. We will discuss the biological mechanisms involved and the relevance of neuronal vulnerability and potential difficulties for future trials and development of therapies.

The Role of Macrophages in Neuroinflammatory and Neurodegenerative Pathways of Alzheimer's Disease, Amyotrophic Lateral Sclerosis, and Multiple Sclerosis: Pathogenetic Cellular Effectors and Potential Therapeutic Targets

In physiological conditions, different types of macrophages can be found within the central nervous system (CNS), i.e., microglia, meningeal macrophages, and perivascular (blood-brain barrier) and choroid plexus (blood-cerebrospinal fluid barrier) macrophages. Microglia and tissue-resident macrophages, as well as blood-borne monocytes, have different origins, as the former derive from yolk sac erythromyeloid precursors and the latter from the fetal liver or bone marrow. Accordingly, specific phenotypic patterns characterize each population. These cells function to maintain homeostasis and are directly involved in the development and resolution of neuroinflammatory processes. Also, following inflammation, circulating monocytes can be recruited and enter the CNS, therefore contributing to brain pathology. These cell populations have now been identified as key players in CNS pathology, including autoimmune diseases, such as multiple sclerosis, and degenerative diseases, such as Amyotrophic Lateral Sclerosis and Alzheimer’s disease. Here, we review the evidence on the involvement of CNS macrophages in neuroinflammation and the advantages, pitfalls, and translational opportunities of pharmacological interventions targeting these heterogeneous cellular populations for the treatment of brain diseases.

Metformin treatment prevents amyloid plaque deposition and memory impairment in APP/PS1 mice

Alzheimer'sdisease(AD) is characterized by deposition of amyloid-β (Aβ)plaques, neurofibrillary tangles, andneuronal loss, accompaniedbyneuroinflammation. Neuroinflammatoryprocesses are thought to contribute toAD pathophysiology. Metformin has been reported to have anti-inflammatory efficacy. However, whether metformin is responsible for the anti-neuroinflammationand neuroprotection on APPswe/PS1ΔE9 (APP/PS1) mice remains unclear. Here we showed that metformin attenuated spatial memory deficit, neuron loss in the hippocampus and enhanced neurogenesis in APP/PS1 mice. In addition, metformin administration decreased amyloid-β (Aβ)plaque load and chronic inflammation (activated microglia and astrocytes as well as pro-inflammatory mediators) in the hippocampus and cortex. Further study demonstrated that treatment with metformin enhanced cerebral AMPK activation. Meanwhile, metformin notably suppressed the activation of P65 NF-κB, mTOR and S6K, reduced Bace1 protein expression. Our data suggest that metformin can exert functional recovery of memory deficits and neuroprotective effect on APP/PS1 mice via triggering neurogenesis and anti-inflammation mediated by regulating AMPK/mTOR/S6K/Bace1 and AMPK/P65 NF-κB signaling pathways in the hippocampus, which may contribute to improvement in neurological deficits.

MicroRNA-31 is required for astrocyte specification

Previously, we determined microRNA-31 (miR-31) is a noncoding tumor suppressive gene frequently deleted in glioblastoma (GBM); miR-31 suppresses tumor growth, in part, by limiting the activity of NF-κB. Herein, we expand our previous studies by characterizing the role of miR-31 during neural precursor cell (NPC) to astrocyte differentiation. We demonstrate that miR-31 expression and activity is suppressed in NPCs by stem cell factors such as Lin28, c-Myc, SOX2 and Oct4. However, during astrocytogenesis, miR-31 is induced by STAT3 and SMAD1/5/8, which mediate astrocyte differentiation. We determined miR-31 is required for terminal astrocyte differentiation, and that the loss of miR-31 impairs this process and/or prevents astrocyte maturation. We demonstrate that miR-31 promotes astrocyte development, in part, by reducing the levels of Lin28, a stem cell factor implicated in NPC renewal. These data suggest that miR-31 deletions may disrupt astrocyte development and/or homeostasis.

A systems medicine approach reveals disordered immune system and lipid metabolism in multiple sclerosis patients

Identification of autoimmune processes and introduction of new autoantigens involved in the pathogenesis of multiple sclerosis (MS) can be helpful in the design of new drugs to prevent unresponsiveness and side effects in patients. To find significant changes, we evaluated the autoantibody repertoires in newly diagnosed relapsing-remitting MS patients (NDP) and those receiving disease-modifying therapy (RP). Through a random peptide phage library, a panel of NDP- and RP-specific peptides was identified, producing two protein data sets visualized using Gephi, based on protein--protein interactions in the STRING database. The top modules of NDP and RP networks were assessed using Enrichr. Based on the findings, a set of proteins, including ATP binding cassette subfamily C member 1 (ABCC1), neurogenic locus notch homologue protein 1 (NOTCH1), hepatocyte growth factor receptor (MET), RAF proto-oncogene serine/threonine-protein kinase (RAF1) and proto-oncogene vav (VAV1) was found in NDP and was involved in over-represented terms correlated with cell-mediated immunity and cancer. In contrast, transcription factor RelB (RELB), histone acetyltransferase p300 (EP300), acetyl-CoA carboxylase 2 (ACACB), adiponectin (ADIPOQ) and phosphoenolpyruvate carboxykinase 2 mitochondrial (PCK2) had major contributions to viral infections and lipid metabolism as significant events in RP. According to these findings, further research is required to demonstrate the pathogenic roles of such proteins and autoantibodies targeting them in MS and to develop therapeutic agents which can ameliorate disease severity.

The Effects of Berberine on Concanavalin A-Induced Autoimmune Hepatitis (AIH) in Mice and the Adenosine 5'-Monophosphate (AMP)-Activated Protein Kinase (AMPK) Pathway

Background

Berberine, a herbal extract, has been reported to protect against inflammatory disorders. The adenosine 5′-monophosphate (AMP)-activated protein kinase (AMPK) signaling pathway can be activated by berberine and inhibited by the synthetic, reversible AMP-competitive inhibitor, Compound C. The aim of this study was to investigate the effects of berberine on concanavalin A (Con A)-induced autoimmune hepatitis (AIH) in mice via the AMPK pathway.

Material/Methods

BALB/c mice were treated with berberine, with or without Compound C, followed by treatment with Con A. Serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were measured. Liver tissue histology was performed to evaluate hepatic injury and AIH. Cytokine levels in serum and hepatic tissue were measured by enzyme-linked immunoassay (ELISA) and used quantitative polymerase chain reaction (qPCR). Levels of phosphorylated acetyl coenzyme-A carboxylase (ACC), representing AMPK activation, were detected by Western blotting.

Results

Serum ALT and AST levels were significantly reduced by berberine (100 and 200 mg/kg/day) in mice with Con A-induced hepatitis. Berberine also reduced Con A-induced hepatocyte swelling, cell death, and infiltration of leukocytes. Serum levels of tumor necrosis factor (TNF)-alpha, interferon (IF)-gamma, interleukin (IL)-2, and IL-1beta were reduced by berberine pre-treatment; levels of serum IL-10, an anti-inflammatory cytokine, was elevated. These protective effects of berberine on Con-A-induced AIH were reversed by treatment with Compound C.

Conclusions

In a murine model of Con A-induced AIH, berberine treatment reduced hepatic injury via activation of the AMPK pathway. Further studies are recommended to determine the potential therapeutic role for berberine in AIH.