Cellular stress signaling activates type-I IFN response through FOXO3-regulated lamin posttranslational modification

Defective mitochondrial COX1 translation due to loss of COX14 function triggers ROS-induced inflammation in mouse liver

Mitochondrial oxidative phosphorylation (OXPHOS) fuels cellular ATP demands. OXPHOS defects lead to severe human disorders with unexplained tissue specific pathologies. Mitochondrial gene expression is essential for OXPHOS biogenesis since core subunits of the complexes are mitochondrial-encoded. COX14 is required for translation of COX1, the central mitochondrial-encoded subunit of complex IV. Here we describe a COX14 mutant mouse corresponding to a patient with complex IV deficiency. COX14M19I mice display broad tissue-specific pathologies. A hallmark phenotype is severe liver inflammation linked to release of mitochondrial RNA into the cytosol sensed by RIG-1 pathway. We find that mitochondrial RNA release is triggered by increased reactive oxygen species production in the deficiency of complex IV. Additionally, we describe a COA3Y72C mouse, affected in an assembly factor that cooperates with COX14 in early COX1 biogenesis, which displays a similar yet milder inflammatory phenotype. Our study provides insight into a link between defective mitochondrial gene expression and tissue-specific inflammation.

Neuregulin-1, a member of the epidermal growth factor family, mitigates STING-mediated pyroptosis and necroptosis in ischaemic flaps

Background

Ensuring the survival of the distal end of a random flap during hypoperfusion (ischaemia) is difficult in clinical practice. Effective prevention of programmed cell death is a potential strategy for inhibiting ischaemic flap necrosis. The activation of stimulator of interferon genes (STING) pathway promotes inflammation and leads to cell death. The epidermal growth factor family member neuregulin-1 (NRG1) reduces cell death by activating the protein kinase B (AKT) signalling pathway. Moreover, AKT signalling negatively regulates STING activity. We aimed to verify the efficacy of NRG1 injection in protecting against flap necrosis. Additionally, we investigated whether NRG1 effectively enhances ischemic flap survival by inhibiting pyroptosis and necroptosis through STING suppression.

Methods

A random-pattern skin flap model was generated on the backs of C57BL/6 mice. The skin flap survival area was determined. The blood supply and vascular network of the flap was assessed by laser Doppler blood flow analysis. Cluster of differentiation 34 immunohistochemistry (IHC) and haematoxylin and eosin (H&E) staining of the flap sections revealed microvessels. Transcriptome sequencing analysis revealed the mechanism by which NRG1 promotes the survival of ischaemic flaps. The levels of angiogenesis, oxidative stress, necroptosis, pyroptosis and indicators associated with signalling pathways in flaps were examined by IHC, immunofluorescence and Western blotting. Packaging adeno-associated virus (AAV) was used to activate STING in flaps.

Results

NRG1 promoted the survival of ischaemic flaps. An increased subcutaneous vascular network and neovascularization were found in ischaemic flaps after the application of NRG1. Transcriptomic gene ontology enrichment analysis and protein level detection indicated that necroptosis, pyroptosis and STING activity were reduced in the NRG1 group. The phosphorylation of AKT and forkhead box O3a (FOXO3a) were increased after NRG1 treatment. The increased expression of STING in flaps induced by AAV reversed the therapeutic effect of NRG1. The ability of NRG1 to phosphorylate AKT-FOXO3a, inhibit STING and promote flap survival was abolished after the application of the AKT inhibitor MK2206.

Conclusions

NRG1 inhibits pyroptosis and necroptosis by activating the AKT-FOXO3a signalling pathway to suppress STING activation and promote ischaemic flap survival.

Identification of a novel FOXO3 agonist that protects against alcohol induced liver injury

Alcohol-related liver disease (ALD) is a global healthcare concern which caused by excessive alcohol consumption with limited treatment options. The pathogenesis of ALD is complex and involves in hepatocyte damage, hepatic inflammation, increased gut permeability and microbiome dysbiosis. FOXO3 is a well-recognized transcription factor which associated with longevity via promoting antioxidant stress response, preventing senescence and cell death, and inhibiting inflammation. We and many others have reported that FOXO3-/- mice develop more severe liver injury in response to alcohol. In the present study, we aimed to develop compounds that activate FOXO3 and further investigate their effects in alcohol induced liver injury. Through virtual screening, we discovered series of small molecular compounds that showed high affinity to FOXO3. We confirmed effects of compounds on FOXO3 target gene expression, as well as antioxidant and anti-apoptotic effects in vitro. Subsequently we evaluated the protective efficacy of compounds in alcohol induced liver injury in vivo. As a result, the leading compound we identified, 214991, activated downstream target genes expression of FOXO3, inhibited intracellular ROS accumulation and cell apoptosis induced by H2O2 and sorafenib. By using Lieber-DeCarli alcohol feeding mouse model, 214991 showed protective effects against alcohol-induced liver inflammation, macrophage and neutrophil infiltration, and steatosis. These findings not only reinforce the potential of FOXO3 as a valuable target for therapeutic intervention of ALD, but also suggested that compound 214991 as a promising candidate for the development of innovative therapeutic strategies of ALD.

Bi-directional regulation of type I interferon signaling by heme oxygenase-1

Moderate activation of IFN-I contributes to the body's immune response, but its abnormal expression, stimulated by oxidative stress or other factors causes pathological damage. Heme oxygenase-1 (HO-1), induced by stress stimuli in the body, exerts a central role in cellular protection. Here we showed that HO-1 could promote IFN-1 under Spring Viremia of Carp virus (SVCV) infection and concomitantly attenuate the replication of SVCV. Further characterization of truncated mutants of HO-1 confirmed that intact HO-1 was essential for its antiviral function via IFN-I. Importantly, HO-1 inhibited the IFN-I signal by degrading the IRF3/7 through the autophagy pathway when it was triggered by H2O2 treatment. The iron ion-binding site (His28) was critical for HO-1 to degrade IRF3/7. HO-1 degradation of IRF3/7 is conserved in fish and mammals. Collectively, HO-1 regulates IFN-I positively under viral infection and negatively under oxidative stress, elucidating a mechanism by which HO-1 regulates IFN-I signaling in bi-directions.

Type I IFN in Glomerular Disease: Scarring beyond the STING

The field of nephrology has recently directed a considerable amount of attention towards the stimulator of interferon genes (STING) molecule since it appears to be a potent driver of chronic kidney disease (CKD). STING and its activator, the cyclic GMP-AMP synthase (cGAS), along with intracellular RIG-like receptors (RLRs) and toll-like receptors (TLRs), are potent inducers of type I interferon (IFN-I) expression. These cytokines have been long recognized as part of the mechanism used by the innate immune system to battle viral infections; however, their involvement in sterile inflammation remains unclear. Mounting evidence pointing to the involvement of the IFN-I pathway in sterile kidney inflammation provides potential insights into the complex interplay between the innate immune system and damage to the most sensitive segment of the nephron, the glomerulus. The STING pathway is often cited as one cause of renal disease not attributed to viral infections. Instead, this pathway can recognize and signal in response to host-derived nucleic acids, which are also recognized by RLRs and TLRs. It is still unclear, however, whether the development of renal diseases depends on subsequent IFN-I induction or other processes involved. This review aims to explore the main endogenous inducers of IFN-I in glomerular cells, to discuss what effects autocrine and paracrine signaling have on IFN-I induction, and to identify the pathways that are implicated in the development of glomerular damage.

PLGA nanoparticles enhanced cardio-protection of scutellarin and paeoniflorin against isoproterenol-induced myocardial ischemia in rats

This study aims to examine the impact of the microfluidic preparation process on the quality of poly (lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) co-delivered with scutellarin (SCU) and paeoniflorin (PAE) in comparison to a conventional emulsification method and to evaluatethe potential cardio-protective effect of SCU-PAE PLGA NPs produced through emulsification method. As compared with microfluidics, the nanoparticles prepared by emulsification method exhibited a smaller size, higher encapsulation efficiency, higher drug loading and lower viscosity for injection. Subsequently, a rat myocardial ischemia (MI) was established using male Sprague-Dawley (SD) rats (250 ± 20 g) subcutaneously injected with 85 mg/kg isoproterenol (ISO) for two consecutive days. The pharmacokinetic findings demonstrated that our SCU-PAE PLGA NPs exhibited prolonged blood circulation time in MI rats, leading to increased levels of SCU and PAE in the heart. This resulted in significant improvements in electrocardiogram and cardiac index, as well as reduced serum levels of CK, LDH, AST. Histopathological analysis using H&E and TUNEL staining provided further evidence of improved cardiac function and decreased apoptosis. Additionally, experiments measuring SOD, MDA, GSH, NO, TNF-α and IL-6 levels indicated that SCU-PAE PLGA NPs may effectively treat MI through oxidative stress and inflammatory pathways, thereby establishing it as a promising therapeutic intervention.

Calorie restriction modulates the transcription of genes related to stress response and longevity in human muscle: The CALERIE study

The lifespan extension induced by 40% caloric restriction (CR) in rodents is accompanied by postponement of disease, preservation of function, and increased stress resistance. Whether CR elicits the same physiological and molecular responses in humans remains mostly unexplored. In the CALERIE study, 12% CR for 2 years in healthy humans induced minor losses of muscle mass (leg lean mass) without changes of muscle strength, but mechanisms for muscle quality preservation remained unclear. We performed high-depth RNA-Seq (387-618 million paired reads) on human vastus lateralis muscle biopsies collected from the CALERIE participants at baseline, 12- and 24-month follow-up from the 90 CALERIE participants randomized to CR and "ad libitum" control. Using linear mixed effect model, we identified protein-coding genes and splicing variants whose expression was significantly changed in the CR group compared to controls, including genes related to proteostasis, circadian rhythm regulation, DNA repair, mitochondrial biogenesis, mRNA processing/splicing, FOXO3 metabolism, apoptosis, and inflammation. Changes in some of these biological pathways mediated part of the positive effect of CR on muscle quality. Differentially expressed splicing variants were associated with change in pathways shown to be affected by CR in model organisms. Two years of sustained CR in humans positively affected skeletal muscle quality, and impacted gene expression and splicing profiles of biological pathways affected by CR in model organisms, suggesting that attainable levels of CR in a lifestyle intervention can benefit muscle health in humans.

CEGA: a method for inferring natural selection by comparative population genomic analysis across species

We developed maximum likelihood method for detecting positive selection or balancing selection using multilocus or genomic polymorphism and divergence data from two species. The method is especially useful for investigating natural selection in noncoding regions. Simulations demonstrate that the method outperforms existing methods in detecting both positive and balancing selection. We apply the method to population genomic data from human and chimpanzee. The list of genes identified under selection in the noncoding regions is prominently enriched in pathways related to the brain and nervous system. Therefore, our method will serve as a useful tool for comparative population genomic analysis.

Methionine restriction promotes cGAS activation and chromatin untethering through demethylation to enhance antitumor immunity

Cyclic GMP-AMP synthase (cGAS) is the major sensor for cytosolic DNA and activates type I interferon signaling and plays an essential role in antitumor immunity. However, it remains unclear whether the cGAS-mediated antitumor activity is affected by nutrient status. Here, our study reports that methionine deprivation enhances cGAS activity by blocking its methylation, which is catalyzed by methyltransferase SUV39H1. We further show that methylation enhances the chromatin sequestration of cGAS in a UHRF1-dependent manner. Blocking cGAS methylation enhances cGAS-mediated antitumor immunity and suppresses colorectal tumorigenesis. Clinically, cGAS methylation in human cancers correlates with poor prognosis. Thus, our results indicate that nutrient stress promotes cGAS activation via reversible methylation, and suggest a potential therapeutic strategy for targeting cGAS methylation in cancer treatment.

Association between tissue stress reaction and ACE2/TMPRSS2 expression in endometria of reproductive aged women before and during Covid-19 pandemic

BACKGROUND

A potential concern has been raised regarding fertility and reproductive outcome during the Covid-19 pandemic with growing stress and anxiety. However, information on the association between tissue stress reaction and expression profiles of SARS-CoV-2 viral entry proteins, ACE2 and TMPRSS2, in endometria collected from women before (pre-pandemic) and during the Covid-19 pandemic (in-pandemic) is unknown. We aim to investigate the relationship between the expression of stress-reactive proteins and of ACE2 and TMPRSS2 in endometria collected from women during these two different time frames.

METHODS

We retrospectively retrieved tissue blocks of endometrial samples from 25 women in 2019 (pre-pandemic) and 25 women in 2020 (in-pandemic) who underwent hysterectomy for different gynecological indications. Immunohistochemical analysis was performed with endometrial tissue samples that were collected before and during the pandemic, using respective antibodies targeting ACE2/TMPRSS2, ADRB2 and NK1R (stress and anxiety receptor markers, respectively). The quantification of immunoreactive cells for each marker was calculated by the immunoreactive score (IRS) analysis. This retrospective cohort study was limited to small sample size.

RESULTS

No significant differences in the IRS of ACE2 and TMPRSS2 were found between the endometria that were collected before and during the pandemic with a lack of correlation between ACE2 and TMPRSS2 expression in respective endometria (r = 0.11, pre-pandemic; r = 0.04, in-pandemic). The immunostaining levels of stress marker, ADRB2 were significantly higher in the endometria of in-pandemic group (p = 0.015) comparing to that of pre-pandemic group. Pearson's correlation coefficient analysis showed a significant correlation in the expression between ADRB2 and TMPRSS2 (r = 0.41, p = 0.042) in the endometria of in-pandemic group but not in the pre-pandemic group.

CONCLUSION

The rise in stress and anxiety among women during current pandemic may elicit substantial amount of tissue stress reaction with consequent increase in the expression of SARS-CoV-2 viral entry proteins in their endometria. A lack of correlation between ACE2 and TMPRSS2 expression in endometria may reassure women in their reproductive age that they are not more susceptible to infection by SARS-CoV-2 and suggest that stressful women during this pandemic can safely decide to conceive naturally or by artificial reproductive technology.

Role of CD14+ monocyte-derived oxidised mitochondrial DNA in the inflammatory interferon type 1 signature in juvenile dermatomyositis

OBJECTIVES

To define the host mechanisms contributing to the pathological interferon (IFN) type 1 signature in Juvenile dermatomyositis (JDM).

METHODS

RNA-sequencing was performed on CD4+, CD8+, CD14+ and CD19+ cells sorted from pretreatment and on-treatment JDM (pretreatment n=10, on-treatment n=11) and age/sex-matched child healthy-control (CHC n=4) peripheral blood mononuclear cell (PBMC). Mitochondrial morphology and superoxide were assessed by fluorescence microscopy, cellular metabolism by 13C glucose uptake assays, and oxidised mitochondrial DNA (oxmtDNA) content by dot-blot. Healthy-control PBMC and JDM pretreatment PBMC were cultured with IFN-α, oxmtDNA, cGAS-inhibitor, TLR-9 antagonist and/or n-acetyl cysteine (NAC). IFN-stimulated gene (ISGs) expression was measured by qPCR. Total numbers of patient and controls for functional experiments, JDM n=82, total CHC n=35.

RESULTS

Dysregulated mitochondrial-associated gene expression correlated with increased ISG expression in JDM CD14+ monocytes. Altered mitochondrial-associated gene expression was paralleled by altered mitochondrial biology, including 'megamitochondria', cellular metabolism and a decrease in gene expression of superoxide dismutase (SOD)1. This was associated with enhanced production of oxidised mitochondrial (oxmt)DNA. OxmtDNA induced ISG expression in healthy PBMC, which was blocked by targeting oxidative stress and intracellular nucleic acid sensing pathways. Complementary experiments showed that, under in vitro experimental conditions, targeting these pathways via the antioxidant drug NAC, TLR9 antagonist and to a lesser extent cGAS-inhibitor, suppressed ISG expression in pretreatment JDM PBMC.

CONCLUSIONS

These results describe a novel pathway where altered mitochondrial biology in JDM CD14+ monocytes lead to oxmtDNA production and stimulates ISG expression. Targeting this pathway has therapeutical potential in JDM and other IFN type 1-driven autoimmune diseases.

Scutellarin ameliorates ischemia/reperfusion injury‑induced cardiomyocyte apoptosis and cardiac dysfunction via inhibition of the cGAS‑STING pathway

Ischemic heart disease is a common cardiovascular disease. Scutellarin (SCU) exhibits protective effects in ischemic cardiomyocytes; however, to the best of our knowledge, the protective mechanism of SCU remains unclear. The present study was performed to investigate the protective effect of SCU on cardiomyocytes after ischemia/reperfusion (I/R) injury and the underlying mechanism. Mice were intraperitoneally injected with SCU (20 mg/kg) for 7 days before establishing the heart I/R injury model. Cardiac function was detected using small animal echocardiography, apoptotic cells were visualized using TUNEL staining, the myocardial infarct area was assessed by 2,3,5-triphenyltetrazolium chloride staining, and the protein levels of cyclic GMP-AMP synthase (cGAS), stimulator of interferon genes (STING), Bcl-2, Bax and cleaved Caspase-3 were detected by western blotting. In in vitro experiments, H9c2 cells were pretreated with SCU, RU.521 (cGAS inhibitor) and H-151 (STING inhibitor), before cell hypoxia/reoxygenation (H/R) injury. The viability of H9c2 cells was detected using a Cell Counting Kit-8 assay, the rate of apoptosis was determined by flow cytometry, and the protein expression levels of cGAS, STING, Bcl-2, Bax and cleaved Caspase-3 were detected by western blotting. It was revealed that SCU ameliorated cardiac dysfunction and apoptosis, and inhibited the activation of the cGAS-STING and Bcl-2/Bax/Caspase-3 signaling pathways in I/R-injured mice. It was also observed that SCU significantly increased cell viability and decreased apoptosis in H/R-induced H9c2 cells. Furthermore, H/R increased the expression levels of cGAS, STING and cleaved Caspase-3, and decreased the ratio of Bcl-2/Bax, which could be reversed by treatment with SCU, RU.521 and H-151. The present study demonstrated that the cGAS-STING signaling pathway may be involved in the regulation of the activation of the Bcl-2/Bax/Caspase-3 signaling pathway to mediate I/R-induced cardiomyocyte apoptosis and cardiac dysfunction, which could be ameliorated by SCU treatment.

Single cell transcriptomics reveals reduced stress response in stem cells manipulated using localized electric fields

Membrane disruption using Bulk Electroporation (BEP) is a widely used non-viral method for delivering biomolecules into cells. Recently, its microfluidic counterpart, Localized Electroporation (LEP), has been successfully used for several applications ranging from reprogramming and engineering cells for therapeutic purposes to non-destructive sampling from live cells for temporal analysis. However, the side effects of these processes on gene expression, that can affect the physiology of sensitive stem cells are not well understood. Here, we use single cell RNA sequencing (scRNA-seq) to investigate the effects of BEP and LEP on murine neural stem cell (NSC) gene expression. Our results indicate that unlike BEP, LEP does not lead to extensive cell death or activation of cell stress response pathways that may affect their long-term physiology. Additionally, our demonstrations show that LEP is suitable for multi-day delivery protocols as it enables better preservation of cell viability and integrity as compared to BEP.

Ageing and rejuvenation of tissue stem cells and their niches

Most adult organs contain regenerative stem cells, often organized in specific niches. Stem cell function is critical for tissue homeostasis and repair upon injury, and it is dependent on interactions with the niche. During ageing, stem cells decline in their regenerative potential and ability to give rise to differentiated cells in the tissue, which is associated with a deterioration of tissue integrity and health. Ageing-associated changes in regenerative tissue regions include defects in maintenance of stem cell quiescence, differentiation ability and bias, clonal expansion and infiltration of immune cells in the niche. In this Review, we discuss cellular and molecular mechanisms underlying ageing in the regenerative regions of different tissues as well as potential rejuvenation strategies. We focus primarily on brain, muscle and blood tissues, but also provide examples from other tissues, such as skin and intestine. We describe the complex interactions between different cell types, non-cell-autonomous mechanisms between ageing niches and stem cells, and the influence of systemic factors. We also compare different interventions for the rejuvenation of old regenerative regions. Future outlooks in the field of stem cell ageing are discussed, including strategies to counter ageing and age-dependent disease.

FoxO3 Regulates the Progress and Development of Aging and Aging-Related Diseases

Aging is an inevitable risk factor for many diseases, including cardiovascular diseases, neurodegenerative diseases, cancer, and diabetes. Investigation into the molecular mechanisms involved in aging and longevity will benefit the treatment of age-dependent diseases and the development of preventative medicine for agingrelated diseases. Current evidence has revealed that FoxO3, encoding the transcription factor (FoxO)3, a key transcription factor that integrates different stimuli in the intrinsic and extrinsic pathways and is involved in cell differentiation, protein homeostasis, stress resistance and stem cell status, plays a regulatory role in longevity and in age-related diseases. However, the precise mechanisms by which the FoxO3 transcription factor modulates aging and promotes longevity have been unclear until now. Here, we provide a brief overview of the mechanisms by which FoxO3 mediates signaling in pathways involved in aging and aging-related diseases, as well as the current knowledge on the role of the FoxO3 transcription factor in the human lifespan and its clinical prospects. Ultimately, we conclude that FoxO3 signaling pathways, including upstream and downstream molecules, may be underlying therapeutic targets in aging and age-related diseases.

A FOXO1-dependent transcription network is a targetable vulnerability of mantle cell lymphomas

Targeting lineage-defined transcriptional dependencies has emerged as an effective therapeutic strategy in cancer treatment. Through screening for molecular vulnerabilities of mantle cell lymphoma (MCL), we identified a set of transcription factors (TFs) including FOXO1, EBF1, PAX5, and IRF4 that are essential for MCL propagation. Integrated chromatin immunoprecipitation and sequencing (ChIP-Seq) with transcriptional network reconstruction analysis revealed FOXO1 as a master regulator that acts upstream in the regulatory TF hierarchy. FOXO1 is both necessary and sufficient to drive MCL lineage commitment through supporting the lineage-specific transcription programs. We further show that FOXO1, but not its close paralog FOXO3, can reprogram myeloid leukemia cells and induce B-lineage gene expression. Finally, we demonstrate that cpd10, a small molecule identified from an enriched FOXO1 inhibitor library, induces a robust cytotoxic response in MCL cells in vitro and suppresses MCL progression in vivo. Our findings establish FOXO1 inhibition as a therapeutic strategy targeting lineage-driven transcriptional addiction in MCL.

FOXO transcription factors as therapeutic targets in human diseases

Forkhead box (FOX)O proteins are transcription factors (TFs) with four members in mammals designated FOXO1, FOXO3, FOXO4, and FOXO6. FOXO TFs play a pivotal role in the cellular adaptation to diverse stress conditions. FOXO proteins act as context-dependent tumor suppressors and their dysregulation has been implicated in several age-related diseases. FOXO3 has been established as a major gene for human longevity. Accordingly, FOXO proteins have emerged as potential targets for the therapeutic development of drugs and geroprotectors. In this review, we provide an overview of the most recent advances in our understanding of FOXO regulation and function in various pathological conditions. We discuss strategies targeting FOXOs directly or by the modulation of upstream regulators, shedding light on the most promising intervention points. We also reveal the most relevant clinical indications and discuss the potential, trends, and challenges of modulating FOXO activity for therapeutic purposes.

Post-Translational Modification of Lamins: Mechanisms and Functions

Lamins are the ancient type V intermediate filament proteins contributing to diverse biological functions, such as the maintenance of nuclear morphology, stabilization of chromatin architecture, regulation of cell cycle progression, regulation of spatial-temporal gene expressions, and transduction of mechano-signaling. Deregulation of lamins is associated with abnormal nuclear morphology and chromatin disorganization, leading to a variety of diseases such as laminopathy and premature aging, and might also play a role in cancer. Accumulating evidence indicates that lamins are functionally regulated by post-translational modifications (PTMs) including farnesylation, phosphorylation, acetylation, SUMOylation, methylation, ubiquitination, and O-GlcNAcylation that affect protein stabilization and the association with chromatin or associated proteins. The mechanisms by which these PTMs are modified and the relevant functionality become increasingly appreciated as understanding of these changes provides new insights into the molecular mechanisms underlying the laminopathies concerned and novel strategies for the management. In this review, we discussed a range of lamin PTMs and their roles in both physiological and pathological processes, as well as potential therapeutic strategies by targeting lamin PTMs.

PI3K-regulated Glycine N-methyltransferase is required for the development of prostate cancer

Glycine N-Methyltransferase (GNMT) is a metabolic enzyme that integrates metabolism and epigenetic regulation. The product of GNMT, sarcosine, has been proposed as a prostate cancer biomarker. This enzyme is predominantly expressed in the liver, brain, pancreas, and prostate tissue, where it exhibits distinct regulation. Whereas genetic alterations in GNMT have been associated to prostate cancer risk, its causal contribution to the development of this disease is limited to cell line-based studies and correlative human analyses. Here we integrate human studies, genetic mouse modeling, and cellular systems to characterize the regulation and function of GNMT in prostate cancer. We report that this enzyme is repressed upon activation of the oncogenic Phosphoinositide-3-kinase (PI3K) pathway, which adds complexity to its reported dependency on androgen signaling. Importantly, we demonstrate that expression of GNMT is required for the onset of invasive prostate cancer in a genetic mouse model. Altogether, our results provide further support of the heavy oncogenic signal-dependent regulation of GNMT in prostate cancer.

ER stress promotes mitochondrial DNA mediated type-1 interferon response in beta-cells and interleukin-8 driven neutrophil chemotaxis

Beta-cell destruction in type 1 diabetes (T1D) results from the combined effect of inflammation and recurrent autoimmunity. Accumulating evidence suggests the engagement of cellular stress during the initial stage of the disease, preceding destruction and triggering immune cell infiltration. While the role of the endoplasmic reticulum (ER) in this process has been largely described, the participation of the other cellular organelles, particularly the mitochondria which are central mediator for beta-cell survival and function, remains poorly investigated. Here, we have explored the contribution of ER stress, in activating type-I interferon signaling and innate immune cell recruitment. Using human beta-cell line EndoC-βH1 exposed to thapsigargin, we demonstrate that induction of cellular stress correlates with mitochondria dysfunction and a significant accumulation of cytosolic mitochondrial DNA (mtDNA) that triggers neutrophils migration by an IL8-dependent mechanism. These results provide a novel mechanistic insight on how ER stress can cause insulitis and may ultimately facilitate the identification of potential targets to protect beta-cells against immune infiltration.

FOXO transcription factors in antioxidant defense

Forkhead box, class O (FOXO) family proteins are widely expressed and highly conserved transcriptional regulators that modulate cellular fuel metabolism, stress resistance and cell death. FOXO target genes include genes encoding antioxidant proteins, thus likely contributing to the key role FOXOs play in the cellular response to oxidative stress and supporting the cellular strategies of antioxidant defense, that is, prevention (of the formation of reactive oxygen species), interception (of reactive species prior to their reaction with cellular components), repair (of damaged biomolecules), and adaptation (i.e., the stimulation of signaling pathways allowing for the expression of protective proteins). FOXOs themselves are regulated by redox processes at several levels, including expression of FOXO genes and enzymatic as well as nonenzymatic posttranslational modifications of FOXO proteins. The latter include modifications of FOXO cysteine residues. Here, an overview is provided on (i) the contribution of FOXO target genes to cellular antioxidative strategies, and (ii) on the impact of thiol homeostasis and thiol modification on FOXO activity.

Oxidative stress sensing and response in neural stem cell fate

Neural stem/progenitor cells (NSPCs) contribute to the physiological cellular turnover of the adult brain and make up its regenerative potential. It is thus essential to understand how different factors influence their proliferation and differentiation to gain better insight into potential therapeutic targets in neurodegenerative diseases and traumatic brain injuries. Recent evidences indicate the roles of redox stress sensing and coping mechanisms in mediating the balance between NSPC self-renewal and differentiation. Such mechanisms involve direct cysteine modification, signaling and metabolic reprogramming, epigenetic alterations and transcription changes leading to adaptive responses like autophagy. Here, we discuss emerging findings on the involvement of redox sensors and effectors and their mechanisms in influencing changes in cellular redox potential and NSPC fate.