Project description:In fungal species, differentiation to the filamentous/hyphal cell type is critical for entry into host cells and virulence. Comparative RNA sequencing was used to explore the pathways that regulate differentiation to the filamentous cell type in yeast. This approach uncovered a role for the stress-response MAPK pathway, HOG, during the increased metabolic respiration that induces filamentous growth. In this context, the AMPK Snf1p and ER stress kinase Ire1p regulated the HOG pathway. Cross-modulation between the HOG and filamentous growth (ERK-type) MAPK pathways optimized the differentiation response. The regulatory circuit described here may extend to behaviors in metazoans. Comparison of expression patterns of wild-type and mutant yeast cells grown in salt, tunicamycin or galactose by comparative RNA sequencing analysis.
Project description:In fungal species, differentiation to the filamentous/hyphal cell type is critical for entry into host cells and virulence. Comparative RNA sequencing was used to explore the pathways that regulate differentiation to the filamentous cell type in yeast. This approach uncovered a role for the stress-response MAPK pathway, HOG, during the increased metabolic respiration that induces filamentous growth. In this context, the AMPK Snf1p and ER stress kinase Ire1p regulated the HOG pathway. Cross-modulation between the HOG and filamentous growth (ERK-type) MAPK pathways optimized the differentiation response. The regulatory circuit described here may extend to behaviors in metazoans.
Project description:Glucocorticoids play central roles in the regulation of energy metabolism by shifting it toward catabolism, while AMPK is the master regulator of energy homeostasis, sensing energy depletion and stimulating pathways of increasing fuel uptake and saving on peripheral supplies. We showed here that AMPK regulates glucocorticoid actions on carbohydrate metabolism by targeting the glucocorticoid receptor (GR) and modifying transcription of glucocorticoid-responsive genes in a tissue- and promoter-specific fashion. Activation of AMPK in rats reversed glucocorticoid-induced hepatic steatosis and suppressed glucocorticoid-mediated stimulation of glucose metabolism. Transcriptomic analysis in the liver suggested marked overlaps between the AMPK and glucocorticoid signaling pathways directed mostly from AMPK to glucocorticoid actions. AMPK accomplishes this by phosphorylating serine 211 of the human GR indirectly through phosphorylation and consequent activation of p38 MAPK and by altering attraction of transcriptional coregulators to DNA-bound GR. In human peripheral mononuclear cells, AMPK mRNA expression positively correlated with that of glucocorticoid-responsive GILZ, which correlated also positively with the body mass index of subjects. These results indicate that the AMPK-mediated energy control system modulates glucocorticoid action at target tissues. Since increased action of glucocorticoids is associated with development of metabolic disorders, activation of AMPK could be a promising target for developing pharmacologic interventions to these pathologies. We tested the hypothesis by treateing rats with the synthetic glucocorticoid dexamethasone and the AMPK activator 5-aminoimidazole-4-carboxamide-1-β-d-ribonucleoside (AICAR).
Project description:TFEB and TFE3 are transcriptional regulators of the innate immune response, but the mechanisms regulating their activation upon pathogen infection are poorly elucidated. Using C. elegans and mammalian models, we report that the master metabolic modulator 5'-AMP-activated protein kinase (AMPK) and its negative regulator Folliculin (FLCN) act upstream of TFEB/TFE3 in the innate immune response, independently of the mTORC1 signaling pathway. In nematodes, loss of FLCN or overexpression of AMPK confers pathogen resistance via activation of TFEB/TFE3- dependent antimicrobial genes, while ablation of total AMPK activity abolishes this phenotype. Similarly, in mammalian cells, loss of FLCN or pharmacological activation of AMPK induces TFEB/TFE3-dependent pro-inflammatory cytokine expression. Importantly, a rapid reduction in cellular ATP levels in murine macrophages is observed upon lipopolysaccharide (LPS) treatment accompanied by an acute AMPK activation and TFEB nuclear localization. These results uncover an ancient, highly conserved and pharmacologically actionable mechanism coupling energy status with innate immunity.
Project description:TFEB and TFE3 are transcriptional regulators of the innate immune response, but the mechanisms regulating their activation upon pathogen infection are poorly elucidated. Using C. elegans and mammalian models, we report that the master metabolic modulator 5'-AMP-activated protein kinase (AMPK) and its negative regulator Folliculin (FLCN) act upstream of TFEB/TFE3 in the innate immune response, independently of the mTORC1 signaling pathway. In nematodes, loss of FLCN or overexpression of AMPK confers pathogen resistance via activation of TFEB/TFE3- dependent antimicrobial genes, while ablation of total AMPK activity abolishes this phenotype. Similarly, in mammalian cells, loss of FLCN or pharmacological activation of AMPK induces TFEB/TFE3-dependent pro-inflammatory cytokine expression. Importantly, a rapid reduction in cellular ATP levels in murine macrophages is observed upon lipopolysaccharide (LPS) treatment accompanied by an acute AMPK activation and TFEB nuclear localization. These results uncover an ancient, highly conserved and pharmacologically actionable mechanism coupling energy status with innate immunity.
Project description:Glucocorticoids play central roles in the regulation of energy metabolism by shifting it toward catabolism, while AMPK is the master regulator of energy homeostasis, sensing energy depletion and stimulating pathways of increasing fuel uptake and saving on peripheral supplies. We showed here that AMPK regulates glucocorticoid actions on carbohydrate metabolism by targeting the glucocorticoid receptor (GR) and modifying transcription of glucocorticoid-responsive genes in a tissue- and promoter-specific fashion. Activation of AMPK in rats reversed glucocorticoid-induced hepatic steatosis and suppressed glucocorticoid-mediated stimulation of glucose metabolism. Transcriptomic analysis in the liver suggested marked overlaps between the AMPK and glucocorticoid signaling pathways directed mostly from AMPK to glucocorticoid actions. AMPK accomplishes this by phosphorylating serine 211 of the human GR indirectly through phosphorylation and consequent activation of p38 MAPK and by altering attraction of transcriptional coregulators to DNA-bound GR. In human peripheral mononuclear cells, AMPK mRNA expression positively correlated with that of glucocorticoid-responsive GILZ, which correlated also positively with the body mass index of subjects. These results indicate that the AMPK-mediated energy control system modulates glucocorticoid action at target tissues. Since increased action of glucocorticoids is associated with development of metabolic disorders, activation of AMPK could be a promising target for developing pharmacologic interventions to these pathologies.
Project description:SARS-CoV-2, the causative agent of the COVID-19 pandemic, drastically modifies infected cells in an effort to optimize virus replication. Included in this process is the activation of the host p38 mitogen-activated protein kinase (MAPK) pathway, which plays a major role in inflammation and is a central driver of COVID-19 clinical presentations. Inhibition of p38/MAPK activity in SARS-CoV-2-infected cells reduces both cytokine production and viral replication. Here, we combined genetic screening with quantitative phosphoproteomics to better understand interactions between the p38/MAPK pathway and SARS-CoV-2. We found several components of the p38/MAPK pathway impact SARS-CoV-2 replication and that p38β is a critical host factor that promotes viral replication and prevents activation of the interferon pathway. Quantitative phosphoproteomics uncovered several SARS-CoV-2 nucleocapsid (N) protein phosphorylation sites near the N-terminus that were sensitive to p38 inhibition. Similar to p38β depletion, mutation of these N residues was associated with reduced viral replication and increased activation of Type I interferon signaling. Taken together, this study reveals a unique proviral function for p38β that is not shared with p38α, and supports efforts to develop p38β inhibitors as a strategy towards developing a new class of COVID-19 therapies. methods
Project description:Type I interferons (IFNs) are key initiators and effectors of the immune response against malignant cells and can also directly inhibit tumor growth. IFN is highly effective in the treatment of myeloproliferative neoplasms (MPNs), but the mechanisms of action are unclear and it remains unknown why some patients respond to IFN therapy and others do not. We have identified and characterized a novel pathway involving PKC upstream of the kinase ULK1. Engagement of the Type I IFN receptor triggers PKC-dependent phosphorylation of ULK1 on serines 341 and 495, required for subsequent engagement of p38 MAPK that regulates transcription of IFN-stimulated genes and subsequent growth inhibitory responses. We show that this pathway is essential for IFN-suppressive effects on primary malignant erythroid precursors from patients with MPNs in vitro, while increased levels of ULK1 and p38 MAPK correlate with clinical response to IFN therapy in MPN patients. IFN treatment also induces cleavage/activation of the ULK1-interacting ROCK1/2 proteins in vivo, triggering a negative feedback loop that suppresses IFN responses. Both ROCK homologs are overexpressed in MPN patients and their genetic or pharmacological inhibition enhances IFN-anti-neoplastic responses in malignant erythroid progenitors from MPN patients. Together, our results identify activation of the PKC-ULK1-p38 MAPK cascade as a key and essential component for the IFN-response, regulated by a feedback loop involving ROCK1/2. These findings suggest the clinical potential of pharmacological inhibition of ROCK1/2 in combination with IFN-therapy for the treatment of MPN patients.
Project description:Reversion from primed to naïve pluripotent status has been achieved by various signaling manipulation, but it is still unclear what signaling is the actual driving force to get over the hurdle from primed to naïve pluripotency. We previously reported that activation of AMP kinase (AMPK) contributed to maintenance of naïve pluripotency. Here, we further show that AMPK activators, AICAR, A769662 or metformin, can induce the reversion of primed mouse epiblast stem cells (mEpiSCs) to naïve pluripotent state. Primed mEpiSCs in our naïve cell culture condition with leukemia inhibitory factor (LIF) and 2 kinase inhibitors (2i) (2iL) never gave rise to naïve state cells. Addition of AICAR alone even in the absence of 2iL or either of AMPK inhibitors with LIF induced appearance of naïve-like cells from primed mEpiSCs. Through maintenance and passages of these cells in 2iL condition, clear naïve-like morphology colonies were purely obtained. They showed core naïve protein expression, and global naïve gene expression profiles. These cells contributed to chimeric mice including germline transmission. Inhibition of p38 signaling abolished the AMPK-elicited reversion and forced activation of p38 in primed mEpiSCs partially reproduced the naïve cell induction, suggesting that p38 is one of the critical downstream in AMPK activation. AMPK pathway should be a novel critical driving force in reversion of primed to naïve pluripotency.
Project description:SARS-CoV-2, the causative agent of the COVID-19 pandemic, drastically modifies the cells that it infects. One such effect is the activation of the host p38 mitogen-activated protein kinase (MAPK) pathway, which plays a major role in inflammation pathways that are dysregulated in severe COVID-19 cases. Inhibition of p38/MAPK activity in SARS-CoV-2-infected cells reduces both cytokine production and viral replication. Here, we applied a systems biology approach to better understand interactions between the p38/MAPK pathway and SARS-CoV-2 in human lung epithelial cells. We found several components of the p38/MAPK pathway positively and negatively impact SARS-CoV-2 infection and that p38ß is a required host factor for SARS-CoV-2 that acts by promoting viral protein translation in a manner that prevents innate immune sensing. Furthermore, we combined chemical and genetic perturbations of p38ß with quantitative phosphoproteomics to identify novel, putative p38ß substrates in an unbiased manner, with broad relevance beyond SARS-CoV-2 biology.