mTOR and STAT3 Pathway Hyper-Activation is Associated with Elevated Interleukin-6 Levels in Patients with Shwachman-Diamond Syndrome: Further Evidence of Lymphoid Lineage Impairment

Distinct peripheral pro-inflammatory profile associated with tuberous sclerosis complex and epilepsy

OBJECTIVE

Tuberous sclerosis complex (TSC) is a monogenetic disorder associated with sustained mechanistic target of rapamycin (mTOR) activation, leading to heterogeneous clinical manifestations. Epilepsy and renal angiomyolipoma are the most important causes of morbidity in adult people with TSC (pwTSC). mTOR is a key player in inflammation, which in turn could influence TSC-related clinical manifestations. Reliable biomarkers are lacking to monitor and predict evolution and response to treatment for epilepsy in pwTSC. Inflammation has been implicated in epileptogenesis in non-TSC-related epilepsy. We aimed to characterize the relation between markers of neuroglial activation/injury, markers of peripheral inflammation, and active epilepsy in pwTSC to identify accessible biomarkers and potential new therapeutic targets.

METHODS

We performed a cross-sectional study to investigate markers of central nervous system (CNS) (neurofilament light [NfL] and glial fibrillary acidic protein [GFAP]) and peripheral (45 cytokines) inflammation in the peripheral blood of pwTSC (n = 46) vs age- and sex-matched healthy controls (HCs) (n = 26). In pwTSC, markers associated with active epilepsy (n = 23/46) were compared to non-TSC epilepsy controls (n = 18). Observations on markers of neuroglial activation/injury (GFAP, NfL) were confirmed in an independent TSC cohort (n = 45; 69% with active epilepsy).

RESULTS

We report that TSC is characterized by elevated serum levels of marker of astrogliosis (GFAP), pro-inflammatory molecules (interleukin 1β [IL-1β], CXCL8) and trophic factor (epidermal growth factor [EGF]) compared to HCs and to non-TSC-related epilepsy controls. Among pwTSC, renal angiomyolipoma presence and size was associated with IL-15. It is notable that active epilepsy in pwTSC was associated with higher levels of GFAP compared to pwTSC without epilepsy, which was confirmed in an external validation cohort, and with elevated levels of pro-inflammatory cytokines (IL-17A, IL-17C, tumor necrosis factor α [TNF-α]), not significantly related to seizure activity or treatment with mTOR inhibitor. These associations remained significant after adjusting for age and sex.

SIGNIFICANCE

These results suggest that key inflammatory mediators could contribute to epileptogenesis and represent novel biomarkers and therapeutic targets in TSC.

CKMT1B regulates the proliferation, migration, invasion, and apoptosis of colorectal cancer cells through the AKT/mTOR/STAT3 pathway

This study aimed to investigate the role of CKMT1B in the growth, migration, invasion, and apoptosis of colorectal cancer (CRC) cells, focusing on its regulation of the AKT/mTOR/STAT3 signaling pathway. Bioinformatics analysis indicated that the CK family expression exhibited heterogeneity and correlation across various cancers, with CKMT1B significantly underexpressed in CRC, suggesting its potential role as a tumor suppressor gene. Additionally, reverse transcription quantitative real-time PCR (RT-qPCR) and Western blot were employed to evaluate CKMT1B expression in CRC cell lines. To assess the effects of CKMT1B knockdown and overexpression in LOVO cells, CCK-8, plate cloning, scratch, Transwell chamber, and Muse assays were used to measure cell proliferation, migration, invasion, and apoptosis. The regulatory mechanism of CKMT1B in CRC was further explored through the AKT/mTOR/STAT3 pathway and related proteins. Downregulation of CKMT1B enhanced the proliferation, migration, and invasion of LOVO cells while inhibiting apoptosis, while CKMT1B overexpression had the opposite effect. Moreover, CKMT1B overexpression led to a decrease in the anti-apoptotic protein BCL2 and an increase in the tumor suppressor protein p53, suggesting its role in modulating apoptotic pathways. The expression levels of the pathway-related proteins P-AKT, P-mTOR, and P-STAT3 were significantly reduced, suggesting that CKMT1B regulates the AKT/mTOR/STAT3 signaling pathway, thereby modulating CRC progression. Taken together, these findings suggest that CKMT1B could serve as a promising molecular target for CRC treatment.

Constitutive systemic inflammation in Shwachman-Diamond Syndrome

BACKGROUND AND PURPOSE

Shwachman-Diamond Syndrome (SDS) is an autosomal recessive disease belonging to the inherited bone marrow failure syndromes and characterized by hypocellular bone marrow, exocrine pancreatic insufficiency, and skeletal abnormalities. SDS is associated with increased risk of developing myelodysplastic syndrome (MDS) and/or acute myeloid leukemia (AML). Although SDS is not primarily considered an inflammatory disorder, some of the associated conditions (e.g., neutropenia, pancreatitis and bone marrow dysfunction) may involve inflammation or immune system dysfunctions. We have already demonstrated that signal transducer and activator of transcription (STAT)-3 and mammalian target of rapamycin (mTOR) were hyperactivated and associated with elevated IL-6 levels in SDS leukocytes. In this study, we analyzed the level of phosphoproteins involved in STAT3 and mTOR pathways in SDS lymphoblastoid cells (LCLs) and the secretomic profile of soluble pro-inflammatory mediators in SDS plasma and LCLs in order to investigate the systemic inflammation in these patients and relative pathways.

METHODS

Twenty-six SDS patients and seven healthy donors of comparable age were recruited during the programmed follow-up visits for clinical evaluation at the Verona Cystic Fibrosis Center Human. The obtained samples (plasma and/or LCLs) were analyzed for: phosphoproteins, cytokines, chemokines and growth factors levels by Bio-plex technology; microRNAs profiling by next generation sequencing (NGS) and microRNAs expression validation by Real Time-PCR (RT-PCR) and droplet digital PCR (ddPCR) .

RESULTS

We demonstrated dysregulation of ERK1/2 and AKT phosphoproteins in SDS, as their involvement in the hyperactivation of the STAT3 and mTOR pathways confirmed the interplay of these pathways in SDS pathophysiology. However, both these signaling pathways are strongly influenced by the inflammatory environment. Here, we reported that SDS is characterized by elevated plasma levels of several soluble proinflammatory mediators. In vitro experiments show that these pro-inflammatory genes are closely correlated with STAT3/mTOR pathway activation. In addition, we found that miR-181a-3p is down-regulated in SDS. Since this miRNA acts as a regulator of several pro-inflammatory pathways such as STAT3 and ERK1/2, its down-regulation may be a driver of the constitutive inflammation observed in SDS patients.

CONCLUSIONS

The results obtained in this study shed light on the complex pathogenetic mechanism underlying bone marrow failure and leukemogenesis in SDS, suggesting the need for anti-inflammatory therapies for SDS patients.

Inactivation of ATG13 stimulates chronic demyelinating pathologies in muscle-serving nerves and spinal cord

Chronic muscle fatigue is a condition characterized by debilitating muscle weakness and pain. Based on our recent finding to study the potential effect of mTOR on ATG13 inactivation in chronic muscle fatigue, we report that biweekly oral administration with MHY1485, a potent inducer of mTOR, develops chronic illness in mice resulting in severe muscle weakness. As a mechanism, we observed that MHY1485 feeding impaired ATG13-dependent autophagy, caused the infiltration of inflammatory M1 macrophages (Mφ), upregulated IL6 and RANTES by STAT3 activation, and augmented demyelination in muscle-serving nerve fibers. Interestingly, these mice displayed worsened muscle fatigue during 2-day post-treadmill exercise, suggesting the critical role of chronic mTOR activation in potential PEM pathogenesis. Interestingly, ATG13-repressor mice exhibited enhanced infiltration of M1Mφ cells, STAT3 activation, demyelination of nerve fibers, and PEM-like symptoms, suggesting the potential role of ATG13 impairment in post-exertional fatigue. HIGHLIGHTS: The potential role of mTOR activation in post-exertional fatigue is highlighted. As a molecular mechanism, mTOR activation augments autophagy impairment via ATG13 inactivation. Autophagy impairment induces IL-6 and RANTES via STAT3, demyelinates nerves in the muscle and spinal cord. ATG13 repressor mice (Tg-ATG13) displayed inflammatory demyelination and post-treadmill fatigue.

Salidroside treatment decreases the susceptibility of atrial fibrillation in diabetic mice by reducing mTOR-STAT3-MCP-1 signaling and atrial inflammation

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia in clinic, and type 2 diabetes mellitus (T2DM) is an independent risk factor for AF. Salidroside (Sal), the active ingredient of the Rhodiola rosea, has hypoglycemic, anti-inflammatory, anti-fibrotic and anti-arrhythmic effects. The aim of this study is to investigate the effects and underlying molecular mechanisms of Sal on T2DM associated atrial inflammation and the pathogenesis of AF. In the in vivo study, T2DM mice model was established by high-fat diet and intraperitoneal injection of streptozotocin (STZ). Sal (25 mg/kg/d, 50 mg/kg/d, and 100 mg/kg/d) was administered orally for 4 weeks. T2DM caused atrial electrical and structural remodeling and significantly increased the susceptibility of AF. Meanwhile, mTOR-STAT3-MCP-1 signaling and inflammatory markers were also significantly enhanced in diabetic atria. However, Sal dose-dependently ameliorated cardiac dysfunction, mitigated atrial structural and electrical remodeling, and reduced atrial inflammation. Moreover, Sal-treated group exhibited remarkably down-regulated activity of mTOR-STAT3-MCP-1 pathway, and decreased atrial monocyte/macrophage infiltration. In palmitic acid (PA)-challenged HL-1 cells, Sal attenuated cytotoxicity, downregulated the expressions of TNF-α, IL-6, MCP-1, and inhibited the activation of mTOR-STAT3 signaling. However, co-treatment with MHY1485 (a mTOR agonist) reversed these effects. Taken together, the present study demonstrates that Sal treatment decreases the susceptibility of AF in diabetic mice by reducing mTOR-STAT3-MCP-1 signaling and atrial monocyte/macrophage infiltration. Sal treatment may represent a novel preventive therapy for cardiac arrhythmia and atrial fibrillation in diabetic patients.

Expression of JAK/STAT Signaling Proteins at Diagnosis and Remission in Patients with Acute Myeloid Leukemia

Objectives

Acute myeloid leukemia (AML), among other malignancies, has been linked to the deregulation of the Janus kinase/signal transducer and activator of transcription (JAK/STAT) signalling pathway, which is essential for cell growth, proliferation, and differentiation. This study aimed to investigate the expression of JAK/STAT proteins at diagnosis and remission and how it affects overall survival (OS).

Methods

This is a prospective study conducted in the College of Medicine, Sultan Qaboos University. Using the enzyme-linked immunosorbent assay assay, we estimated the expression levels of JAK/STAT pathway proteins, including pJAK2, pJAK1, JAK1, pSTAT3, pSTAT5, and STAT5, in peripheral blood and bone marrow samples at diagnosis and remission and normalized to the total protein content. Twenty-three adult AML patients (median age = 47) and seven healthy volunteers, who were used as controls, were included in the study. A total of 68 cell lysates were extracted from samples using peripheral blood mononuclear cells isolation assay.

Results

OS was estimated using the Kaplan-Meier curve, and groups were compared with the COX regression model. The overexpression percent was calculated using the chi-square test (p > 0.050). The study revealed that the expression of JAK1, pJAK1, pJAK2, pSTAT3, STAT5, and pSTAT5 in peripheral blood was lower during the diagnosis phase compared to the remission phase (p > 0.050). All these proteins were overexpressed at diagnosis. These proteins did not impact the OS of AML.

Conclusions

The expression levels of these proteins at the time of diagnosis do not significantly influence the OS of patients with AML. The study is limited in sample size and needs to be confirmed in future studies with a larger sample size.

Endogenous blocking of TLR2 along with TNF-α and IL-1β ameliorates the severity of the S. aureus arthritis via modulating STAT3/SOCS3 expressions in tissue resident macrophages

In vivo studies identifying a role of TLR2 in septic arthritis models are lacking. TNF-α played as the most important proinflammatory cytokine, and connected directly to the pathogenesis of bacterial arthritis. IL-1β is another central mediator cytokine in arthritis. It is therefore reasonable to question the role of neutralization of endogenous TNF-α and IL-1β along with TLR2 and associated downstream signaling as crucial mediators in the S. aureus -induced inflammatory arthritis. In reaction to an injury or a pathogen encounter, innate immune cells serve as the initial line of defense. TLR2 mediated entry of S. aureus into macrophage cells initiates an array of inflammatory cascades. After macrophage cell gets activated at the site inflammation, they generate elevated number of cytokines which includes TNF-α, IL-1β. This cytokines signals through STAT1/STAT3 mediated pathways. Thus, aim of this study was to discover how This bone damage could be altered by altering the STAT/STAT3/SOCS3 ratio by blocking TLR2, a particular S. aureus binding site, in conjunction with the use of IL-1 and TNF- antibodies for neutralizing endogenous IL-1β and TNF-α. Additionally, the role of local macrophages in therapy of arthritis was investigated in synovial and Splenic tissue. To comprehend the inflammatory milieu within the system, ROS and other antioxidant enzymes, along with the expression of mTOR in macrophage cells, were also taken into consideration. The detrimental impact of bacterial burden on synovial joints was reduced by simultaneously inhibiting TLR2, TNF-α, and IL-1β. Lowered IFN-γ decreases its sensitivity to STAT1 and lowered IL-6 reduces STAT3 expressions. Whereas, elevated IL-10 enhances SOSC3 expression, which thereby able to limits STAT1/STAT3 inter-conversion. As a result, NF-κB activity was downregulated.

The metabolic basis of inherited neutropenias

Neutrophils are the shortest-lived blood cells, which requires a prodigious degree of proliferation and differentiation to sustain physiologically sufficient numbers and be poised to respond quickly to infectious emergencies. More than 107 neutrophils are produced every minute in an adult bone marrow-a process that is tightly regulated by a small group of cytokines and chemical mediators and dependent on nutrients and energy. Like granulocyte colony-stimulating factor, the primary growth factor for granulopoiesis, they stimulate signalling pathways, some affecting metabolism. Nutrient or energy deficiency stresses the survival, proliferation, and differentiation of neutrophils and their precursors. Thus, it is not surprising that monogenic disorders related to metabolism exist that result in neutropenia. Among these are pathogenic mutations in HAX1, G6PC3, SLC37A4, TAFAZZIN, SBDS, EFL1 and the mitochondrial disorders. These mutations perturb carbohydrate, lipid and/or protein metabolism. We hypothesize that metabolic disturbances may drive the pathogenesis of a subset of inherited neutropenias just as defects in DNA damage response do in Fanconi anaemia, telomere maintenance in dyskeratosis congenita and ribosome formation in Diamond-Blackfan anaemia. Greater understanding of metabolic pathways in granulopoiesis will identify points of vulnerability in production and may point to new strategies for the treatment of neutropenias.

Shwachman-Diamond syndromes: clinical, genetic, and biochemical insights from the rare variants

Shwachman-Diamond syndrome is a rare inherited bone marrow failure syndrome characterized by neutropenia, exocrine pancreatic insufficiency, and skeletal abnormalities. In 10-30% of cases, transformation to a myeloid neoplasm occurs. Approximately 90% of patients have biallelic pathogenic variants in the SBDS gene located on human chromosome 7q11. Over the past several years, pathogenic variants in three other genes have been identified to cause similar phenotypes; these are DNAJC21, EFL1, and SRP54. Clinical manifestations involve multiple organ systems and those classically associated with the Shwachman-Diamond syndrome (bone, blood, and pancreas). Neurocognitive, dermatologic, and retinal changes may also be found. There are specific gene-phenotype differences. To date, SBDS, DNAJC21, and SRP54 variants have been associated with myeloid neoplasia. Common to SBDS, EFL1, DNAJC21, and SRP54 is their involvement in ribosome biogenesis or early protein synthesis. These four genes constitute a common biochemical pathway conserved from yeast to humans that involve early stages of protein synthesis and demonstrate the importance of this synthetic pathway in myelopoiesis.

The Molecular and Genetic Mechanisms of Inherited Bone Marrow Failure Syndromes: The Role of Inflammatory Cytokines in Their Pathogenesis

Inherited bone marrow failure syndromes (IBMFSs) include Fanconi anemia, Diamond-Blackfan anemia, Shwachman-Diamond syndrome, dyskeratosis congenita, severe congenital neutropenia, and other rare entities such as GATA2 deficiency and SAMD9/9L mutations. The IBMFS monogenic disorders were first recognized by their phenotype. Exome sequencing has validated their classification, with clusters of gene mutations affecting DNA damage response (Fanconi anemia), ribosome structure (Diamond-Blackfan anemia), ribosome assembly (Shwachman-Diamond syndrome), or telomere maintenance/stability (dyskeratosis congenita). The pathogenetic mechanisms of IBMFSs remain to be characterized fully, but an overarching hypothesis states that different stresses elicit TP53-dependent growth arrest and apoptosis of hematopoietic stem, progenitor, and precursor cells. Here, we review the IBMFSs and propose a role for pro-inflammatory cytokines, such as TGF-β, IL-1β, and IFN-α, in mediating the cytopenias. We suggest a pathogenic role for cytokines in the transformation to myeloid neoplasia and hypothesize a role for anti-inflammatory therapies.

Antitumor Activity of Ferulic Acid Against Ehrlich Solid Carcinoma in Rats via Affecting Hypoxia, Oxidative Stress and Cell Proliferation

Background Ferulic acid is a natural compound commonly found in fruits and vegetables like tomatoes, sweet corn, rice bran, and dong quai. It has various beneficial effects on the body, such as anti-inflammatory, anti-apoptotic, hepatoprotective, cardioprotective, and neuroprotective properties. Aims We conducted a study to investigate the antitumor activity of ferulic acid against Ehrlich solid carcinoma (ESC), specifically by affecting hypoxia-inducible factor (HIF)-1α and its subsequent effects on other factors like nuclear factor erythroid 2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1), cellular Myc (cMyc), cyclin D1, mammalian target of rapamycin (mTOR), and signal transducer and activator of transcription 3 (STAT3). Materials and methods The study involved implanting rats with ESC cells and administering 50 mg/kg of ferulic acid orally daily for eight days. Sections of the muscles with ESC were stained with toluidine blue or immunostained with anti-HIF-1α antibodies. The tumor samples were used to evaluate the expression of HIF-1α, Nrf2, HO-1, cMyc, cyclin D1, mTOR, and STAT3. Results Ferulic acid increased mean survival time, reduced tumor volume and weight, and improved the appearance of the tumor tissue. Furthermore, ferulic acid significantly elevated the expression of Nrf2 and HO-1, while reducing the expression of HIF-1α, Nrf2, HO-1, cMyc, cyclin D1, mTOR, and STAT3. Conclusions Ferulic acid can reduce tumor size and weight while improving the structure of muscle cells, suggesting it may have antineoplastic activity against ESC. Further investigation revealed that ferulic acid downregulates HIF-1α, increasing the expression of antioxidant proteins Nrf2 and HO-1. Additionally, ferulic acid decreases the expression of proliferation markers cMyc and cyclin D1 and downregulates cellular regulators mTOR and STAT3.

Cytokine signaling pathway in cystic fibrosis: expression of SOCS and STATs genes in different clinical phenotypes of the disease

This was an observational cross-sectional study which was done to assess the expression profile of STATs and SOCS genes in cystic fibrosis. The mRNA was isolated from peripheral blood mononuclear cells of CF patients in exacerbation, colonization and post exacerbation phases of the disease. The relative gene expression level for SOCS 1, -3, -5 and STAT 1, -3,-4,-6 genes was quantified by Real-time PCR. The levels of IL-6 were also measured in the serum by ELISA. The expression of the Th1 pathway associated genes (SOCS1, SOCS5, STAT4 and STAT1) was downregulated while the expression of Th2/Th17 pathway genes (SOCS3, STAT3, STAT6) was upregulated in both exacerbation and colonization phases as compared to healthy controls. The serum levels of IL-6 were also elevated in both the disease groups. After antibiotic treatment, the expression of SOCS5 and STAT4 was increased while the expression of rest of the genes showed downregulation which shows a shift in immune response from Th2/Th17 to Th1. Our results suggest that infection alters the cytokine signaling pathway through modulation of STATs and SOCS genes which is not able to regulate the overstimulation of cytokine signaling further leading to chronic inflammation in CF.

Targeting STAT3 and STAT5 in Cancer

Insights into the mutational landscape of the human cancer genome coding regions defined about 140 distinct cancer driver genes in 2013, which approximately doubled to 300 in 2018 following advances in systems cancer biology studies [...].