ATF4-dependent and independent mitokine secretion from OPA1 deficient skeletal muscle in mice is sexually dimorphic.

Introduction: Reducing Optic Atrophy 1 (OPA1) expression in skeletal muscle in male mice induces Activation Transcription Factor 4 (ATF4) and the integrated stress response (ISR). Additionally, skeletal muscle secretion of Fibroblast Growth Factor 21 (FGF21) is increased, which mediates metabolic adaptations including resistance to diet-induced obesity (DIO) and glucose intolerance in these mice. Although FGF21 induction in this model can be reversed with pharmacological attenuation of ER stress, it remains to be determined if ATF4 is responsible for FGF21 induction and its metabolic benefits in this model. Methods: We generated mice with homozygous floxed Opa1 and Atf4 alleles and a tamoxifen-inducible Cre transgene controlled by the human skeletal actin promoter to enable simultaneous depletion of OPA1 and ATF4 in skeletal muscle (mAO DKO). Mice were fed high fat (HFD) or control diet and evaluated for ISR activation, body mass, fat mass, glucose tolerance, insulin tolerance and circulating concentrations of FGF21 and growth differentiation factor 15 (GDF15). Results: In mAO DKO mice, ATF4 induction is absent. Other indices of ISR activation, including XBP1s, ATF6, and CHOP were induced in mAO DKO males, but not in mOPA1 or mAO DKO females. Resistance to diet-induced obesity was not reversed in mAO DKO mice of both sexes. Circulating FGF21 and GDF15 illustrated sexually dimorphic patterns. Loss of OPA1 in skeletal muscle increases circulating FGF21 in mOPA1 males, but not in mOPA1 females. Additional loss of ATF4 decreased circulating FGF21 in mAO DKO male mice, but increased circulating FGF21 in female mAO DKO mice. Conversely, circulating GDF15 was increased in mAO DKO males and mOPA1 females, but not in mAO DKO females. Conclusion: Sex differences exist in the transcriptional outputs of the ISR following OPA deletion in skeletal muscle. Deletion of ATF4 in male and female OPA1 KO mice does not reverse the resistance to DIO. Induction of circulating FGF21 is ATF4 dependent in males, whereas induction of circulating GDF15 is ATF4 dependent in females. Elevated GDF15 in males and FGF21 in females could reflect activation by other transcriptional outputs of the ISR, that maintain mitokine-dependent metabolic protection in an ATF4-independent manner.

GDF-15 and mtDNA Deletions Are Useful Biomarkers of Mitochondrial Dysfunction in Insulin Resistance and PCOS.

There is no literature available about the growth differentiation factor-15 (GDF-15) biomarker in combination with mitochondrial DNA (mtDNA) deletions in insulin resistance (IR), and polycystic ovary syndrome (PCOS); however, it would be useful to achieve optimal metabolic status and improve pregnancy success. In this study, the role of GDF-15 and mtDNA deletions as biomarkers in the pathogenesis of IR and PCOS was investigated. In our study, 81 female patients who were treated for IR and/or PCOS and 41 healthy controls were included. GDF-15 levels in patients showed a marked increase compared to controls. Elevated GDF-15 levels were found in 12 patients; all of them had a BMI > 25 kg/m2, which is associated with reactive hyperinsulinemia. The presence of mitochondrial dysfunction was mainly observed in the IR-only subgroup. The increase in plasma levels of GDF-15 and the prevalence of mtDNA deletions is directly proportional to body mass index. The more marked metabolic abnormalities required more intensive drug therapy with a parallel increase in plasma GDF-15 levels. Elevated levels of GDF-15 and the presence of mitochondrial DNA deletions may be a consequence of carbohydrate metabolism disorders in patients and thus a predictor of the process of accelerated aging.

Soluble Urokinase-Type Plasminogen Activator Receptor (suPAR), Growth Differentiation Factor-15 (GDF-15), and Soluble C5b-9 (sC5b-9) Levels Are Significantly Associated with Endothelial Injury Indices in CAR-T Cell Recipients.

Endothelial injury indices, such as Endothelial Activation and Stress Index (EASIX), modified EASIX (m-EASIX), and simplified EASIX (s-EASIX) scores, have been previously associated with chimeric antigen receptor-T (CAR-T) cell immunotherapy complications. Soluble urokinase-type plasminogen activator receptor (suPAR), growth differentiation factor-15 (GDF-15), and soluble C5b-9 (sC5b-9) have been described as markers of endothelial injury post-hematopoietic stem cell transplantation. In the current study, we examined whether suPAR, GDF-15, and sC5b-9 levels were associated with endothelial injury indices in adult CAR-T cell recipients. The levels of these markers were measured in patients before CAR-T cell infusion and in healthy individuals with immunoenzymatic methods. We studied 45 CAR-T cell recipients and 20 healthy individuals as the control group. SuPAR, GDF-15, and sC5b-9 levels were significantly higher in the patients' group compared to the healthy control group (p < 0.001, in all comparisons). SuPAR levels at baseline were associated with the m-EASIX scores calculated at the same time point (p = 0.020), while suPAR and GDF-15 concentrations were correlated with EASIX scores at day 14 post-infusion (p < 0.001 in both comparisons). Moreover, sC5b-9 levels were correlated with the s-EASIX scores at infusion (p = 0.008) and the EASIX scores at day 14 (p = 0.005). In our study, sC5b9, suPAR, and GDF-15 levels were found to reflect endothelial injury in CAR-T cell recipients.

Withaferin A ameliorates ovarian cancer-induced renal damage through the regulation of expression of inflammatory cytokines.

BACKGROUND: Cachexia a multifactorial syndrome is a common sequala in patients with cancer. It varies from 42 to 80% depending upon the oncological stage and is directly responsible for 30% of deaths in these patients. Previous research from our laboratory demonstrated that peritoneal ovarian cancer generated in NSG mice resulted in skeletal and cardiac muscle atrophy - leading to loss of skeletal muscle mass and strength, and cardiac dysfunction (cachexia). Treatment of mice bearing i.p. tumors with withaferin A (WFA) showed reversal of skeletal muscle and cardiac cachexia. The present study is focused on determining effects of peritoneal ovarian tumors on kidney damage and effects of WFA treatment on ameliorating kidney damage. METHODS: We generated intraperitoneal ovarian cancer by injecting female NSG mice with ovarian cancer cell line (A2780). After one week of injecting cancer cells, mice were treated with WFA (4 mg/kg) every third day, for three weeks. After 4 weeks of injection of cancer cells, the mice were sacrificed and various tissues including kidney and blood were collected, snap-frozen in liquid nitrogen, and stored at -800C. The presence of kidney biomarker creatinine, was measured in the plasma by an ELISA. The mRNA was isolated from mouse kidneys and was used to examine the expression levels of signaling proteins, inflammatory cytokines, and genes responsible for inducing cachexia (IL-1ß, IL-6, TNF-α, TGF-ß, GDF-15, and MYD88). RESULTS: Our results showed a significant increase in levels of expression of inflammatory cytokine IL-1 ß (p < 0.01), IL-6 (p < 0.001), TNF-α (p < 0.001), and other related genes including TRAF6 (p < 0.01), MYD88 (p < 0.01), and GDF-15 (p = 0.005) in tumor-bearing mice compared to controls. Treatment of mice bearing tumors with WFA attenuated the increase in expression of each gene. In addition, our results showed a significant increase in creatinine levels in circulation in tumor-bearing mice compared to control mice. Treatment of tumor-bearing mice with WFA resulted in a significant decrease in plasma creatinine levels compared to tumor-bearing mice. CONCLUSIONS: Our results conclude that ovarian tumors in NSG mice caused kidney damage and renal dysfunction, which was effectively ameliorated by WFA treatment, suggesting a protective effect of WFA on kidney injury induced by ovarian cancer.

GDF-15 levels in patients with polycystic ovary syndrome treated with metformin: a combined clinical and in silico pathway analysis.

Objective: Polycystic ovary syndrome (PCOS) is an endocrine disease characterized by metabolic, reproductive, and psychological manifestations. Growth and differentiation factor 15 (GDF-15) is a cytokine associated with metabolic and inflammatory disorders. Metformin is commonly used for the treatment of PCOS. We investigated the relationship between GDF-15 levels and PCOS, the effect of metformin on GDF-15 levels, and potential biologic pathways related to GDF-15. Subjects and methods: The study included 35 women with PCOS and 32 women without PCOS (controls). Both groups were compared in terms of GDF-15 levels. Additional analysis was conducted on samples from 22 women with PCOS who were treated with either metformin (n = 7) or placebo (n = 15), retrieved from a previous randomized, controlled trial. Levels of GDF-15 were measured using MILLIPLEX. The biologic pathways related to GDF-15 were evaluated using the databases STRING, SIGNOR, and Pathway Commons. The statistical analysis was conducted using the software SPSS. Results: Levels of GDF-15 were higher in the PCOS group compared with the non-PCOS group (p = 0.039). Among women with PCOS, GDF-15 levels were higher in those treated with metformin compared with placebo (p = 0.007). The proteins related to GDF-15 overlapped between the databases, and a significant interaction was found between GDF-15 and proteins related to PCOS and its complications, including those related to estrogen response, oxidative stress, ovarian infertility, interleukin (IL)-18, IL-4, the ratio of advanced glycation end products to their receptor (AGE/RAGE), leptin, transforming growth factor beta (TGF-ß), adipogenesis, and insulin. Conclusion: The findings of the present study suggest a relationship between GDF-15 and PCOS and a potential increase in GDF-15 levels with metformin treatment. An additional finding was that GDF-15 could be involved in biologic pathways related to PCOS complications.

Elevated serum GDF15 level as an early indicator of proximal tubular cell injury in acute kidney injury.

Acute kidney injury (AKI) is a high-burden medical condition, and current diagnostic criteria can only assess AKI after full manifestation. Stress marker growth differentiation factor 15 (GDF15) was reported to have a role in kidney injury of critical patients. Herein, we evaluated dynamic changes in GDF15 across diverse AKI scenarios and explored the underlying mechanisms of its induction. Serum parameters and renal lesions were analyzed in mouse models of unilateral ischemia-reperfusion injury (uni-IRI) and unilateral ureteral obstruction (UUO). The human proximal tubular (HK-2) cell line was stimulated with various conditions, and induction of GDF15 expression was determined. Serum GDF15 levels were rapidly induced within hours after injury in both animal models and declined thereafter. Renal GDF15 expression exhibited a temporary and early increased induction and was mainly located in aquaporin 1-positive proximal tubules in both unilateral AKI model tissues. In cell experiments, rapid GDF15 production was highly induced by t-BHP and CoCl2. Treatment with either an antioxidant or mitogen-activated protein kinase inhibitors abolished t-BHP- and CoCl2-mediated GDF15 expression. In addition, silencing nuclear factor erythroid 2-related factor 2 expression also reduced the basal and t-BHP- or CoCl2-mediated GDF15 expression level in HK-2 cells. Our data showed that elevated serum GDF15 levels could be detected early in unilateral AKI models without notable alterations in kidney function parameters. GDF15 expression was associated with oxidative stress- and hypoxia-mediated proximal tubular cell injury. These data document that elevated serum GDF15 can possibly serve as an early biomarker for proximal tubular cell injury in AKI.

GB18-06, a nanobody targeting GDF15, effectively alleviates weight loss and restores physical function in cachexia models.

Cachexia is a complicated metabolic syndrome mainly associated with cancers, characterized by extreme weight loss and muscle wasting. It is a debilitating condition that negatively affects prognosis and survival. However, there is currently no effective pharmacological intervention that can reverse body weight loss and improve physical performance in patients with cachexia. Growth differentiation factor 15 (GDF15) can suppress appetite and regulate energy balance through binding to glial cell-derived neurotrophic factor receptor alpha-like (GFRAL). In order to develop a novel, effective treatment for cachexia, we generated a GDF15-targeting VHH nanobody, GB18-06, that was able to bind GDF15 with high affinity. In vitro, GB18-06 potently inhibited the GDF15-GFRAL signaling pathway, leading to a reduction of downstream ERK and AKT phosphorylation levels; in vivo, GB18-06 alleviated weight loss (>20%) in cancer and chemotherapy-induced cachexia models in mice. Compared with the control (phosphate-buffered saline) group, the ambulatory activity of mice in the GB18-06-treated group also increased 77%. Furthermore, GB18-06 exhibited desirable pharmacokinetic properties and an excellent developability profile. Our study has demonstrated a means of developing targeted treatment for cachexia with high efficacy, potentially leading to improved clinical outcomes and quality of life for patients with cachexia.

Hepatocyte-specific GDF15 overexpression improves high-fat diet-induced obesity and hepatic steatosis in mice via hepatic FGF21 induction.

GDF15 and FGF21, stress-responsive cytokines primarily secreted from the liver, are promising therapeutic targets for metabolic dysfunction-associated steatotic liver disease (MASLD). However, the interaction between GDF15 and FGF21 remains unclear. We examined the effects of hepatocyte-specific GDF15 or FGF21 overexpression in high-fat diet (HFD)-fed mice for 8 weeks. Hydrodynamic injection of GDF15 or FGF21 sustained high circulating levels of GDF15 or FGF21, respectively, resulting in marked reductions in body weight, epididymal fat mass, insulin resistance, and hepatic steatosis. In addition, GDF15 treatment led to early reduction in body weight despite no change in food intake, indicating the role of GDF15 other than appetite loss. GDF15 treatment increased liver-derived serum FGF21 levels, whereas FGF21 treatment did not affect GDF15 expression. GDF15 promoted eIF2α phosphorylation and XBP1 splicing, leading to FGF21 induction. In murine AML12 hepatocytes treated with free fatty acids (FFAs), GDF15 overexpression upregulated Fgf21 mRNA levels and promoted eIF2α phosphorylation and XBP1 splicing. Overall, continuous exposure to excess FFAs resulted in a gradual increase of ß-oxidation-derived reactive oxygen species and endoplasmic reticulum stress, suggesting that GDF15 enhanced this pathway and induced FGF21 expression. GDF15- and FGF21-related crosstalk is an important pathway for the treatment of MASLD.

Mechanism of luteolin induces ferroptosis in nasopharyngeal carcinoma cells.

Nasopharyngeal carcinoma (NPC) originates from the nasopharynx epithelium, and luteolin is recognized as an important anti-cancer agent. This study investigated the effects of luteolin on ferroptosis in NPC cells. NPC cells were cultured and exposed to varying concentrations of luteolin. Cell viability, malondialdehyde (MDA) levels, superoxide dismutase (SOD) activity, glutathione (GSH) levels, Fe2+ concentration, and glutathione peroxidase 4 (GPX4) protein level were assessed. Additionally, SRY-related high-mobility-group box 4 (SOX4) expression was measured. Subsequently, the binding of SOX4 to the growth differentiation factor-15 (GDF15) promoter and GDF15 mRNA levels were evaluated. The impact of the SOX4/GDF15 axis on luteolin-induced ferroptosis in NPC cells was assayed. Luteolin treatment induced cell ferroptosis, evidenced by decreased cell viability, increased MDA and Fe2+ levels, and reduced SOD, GSH, and GPX4 levels. Furthermore, luteolin downregulated SOX4 expression, while overexpression of SOX4 reversed luteolin's pro-ferroptotic effects in NPC cells. SOX4 was found to up-regulate GDF15 transcription by directly binding to its promoter. Conversely, overexpression of GDF15 mitigated the ferroptotic effects induced by luteolin in NPC cells. Therefore, luteolin induces ferroptosis in NPC cells via modulation of the SOX4/GDF15 axis. In conclusion, luteolin reduces the binding of SOX4 to the GDF15 promoter by suppressing SOX4 expression, thereby down-regulating GDF15 transcription levels and inducing ferroptosis in NPC cells.

Prognostic Value of Circulating Fibrosis Biomarkers in Dilated Cardiomyopathy (DCM): Insights into Clinical Outcomes.

BACKGROUND: Dilated cardiomyopathy (DCM) involves myocardial remodeling, characterized by significant fibrosis and extracellular matrix expansion. These changes impair heart function, increasing the risk of heart failure and sudden cardiac death. This study investigates the prognostic value of circulating fibrosis biomarkers as a less invasive method in DCM patients. METHODS: Plasma samples from 185 patients with confirmed DCM were analyzed to measure 13 circulating biomarkers using Luminex bead-based multiplex assays and ELISA. The prognostic value of these biomarkers was evaluated concerning heart failure-associated events and all-cause mortality. RESULTS: Elevated MMP-2 levels (>1519.3 ng/mL) were linked to older age, higher diabetes prevalence, lower HDL, increased NT-proBNP and hs-TnT levels, and severe systolic dysfunction. High TIMP-1 levels (>124.9 ng/mL) correlated with elevated NT-proBNP, more atrial fibrillation, reduced exercise capacity, and larger right ventricles. Increased GDF-15 levels (>1213.9 ng/mL) were associated with older age, systemic inflammation, renal impairment, and poor exercise performance. Elevated OPN levels (>81.7 ng/mL) were linked to higher serum creatinine and NT-proBNP levels. Over a median follow-up of 32.4 months, higher levels of these biomarkers predicted worse outcomes, including increased risks of heart failure-related events and mortality. CONCLUSIONS: Circulating fibrosis biomarkers, particularly MMP-2, TIMP-1, GDF-15, and OPN, are valuable prognostic tools in DCM. They reflect the severity of myocardial remodeling and systemic disease burden, aiding in risk stratification and therapeutic intervention. Integrating these biomarkers into clinical practice could improve DCM management and patient prognosis.

The role of GDF15 in attenuating noise-induced hidden hearing loss by alleviating oxidative stress.

Noise-induced hidden hearing loss (HHL) is a newly uncovered form of hearing impairment that causes hidden damage to the cochlea. Patients with HHL do not have significant abnormalities in their hearing thresholds, but they experience impaired speech recognition in noisy environments. However, the mechanisms underlying HHL remain unclear. In this study, we developed single-cell transcriptome profiles of the cochlea of mice with HHL, detailing changes in individual cell types. Our study revealed a transient threshold shift, reduced auditory brainstem response wave I amplitude, and decreased number of ribbon synapses in HHL mice. Our findings suggest elevated oxidative stress and GDF15 expression in cochlear hair cells of HHL mice. Notably, the upregulation of GDF15 attenuated oxidative stress and auditory impairment in the cochlea of HHL mice. This suggests that a therapeutic strategy targeting GDF15 may be efficacious against HHL.

DNAm scores for serum GDF15 and NT-proBNP levels associate with a range of traits affecting the body and brain.

BACKGROUND: Plasma growth differentiation factor 15 (GDF15) and N-terminal proB-type natriuretic peptide (NT-proBNP) are cardiovascular biomarkers that associate with a range of diseases. Epigenetic scores (EpiScores) for GDF15 and NT-proBNP may provide new routes for risk stratification. RESULTS: In the Generation Scotland cohort (N ≥ 16,963), GDF15 levels were associated with incident dementia, ischaemic stroke and type 2 diabetes, whereas NT-proBNP levels were associated with incident ischaemic heart disease, ischaemic stroke and type 2 diabetes (all PFDR < 0.05). Bayesian epigenome-wide association studies (EWAS) identified 12 and 4 DNA methylation (DNAm) CpG sites associated (Posterior Inclusion Probability [PIP] > 95%) with levels of GDF15 and NT-proBNP, respectively. EpiScores for GDF15 and NT-proBNP were trained in a subset of the population. The GDF15 EpiScore replicated protein associations with incident dementia, type 2 diabetes and ischaemic stroke in the Generation Scotland test set (hazard ratios (HR) range 1.36-1.41, PFDR < 0.05). The EpiScore for NT-proBNP replicated the protein association with type 2 diabetes, but failed to replicate an association with ischaemic stroke. EpiScores explained comparable variance in protein levels across both the Generation Scotland test set and the external LBC1936 test cohort (R2 range of 5.7-12.2%). In LBC1936, both EpiScores were associated with indicators of poorer brain health. Neither EpiScore was associated with incident dementia in the LBC1936 population. CONCLUSIONS: EpiScores for serum levels of GDF15 and Nt-proBNP associate with body and brain health traits. These EpiScores are provided as potential tools for disease risk stratification.

Transcription factor EGR2 alleviates autoimmune uveitis via activation of GDF15 to modulate the retinal microglial phenotype.

Uveitis is a vision-threatening disease primarily driven by a dysregulated immune response, with retinal microglia playing a pivotal role in its progression. Although the transcription factor EGR2 is known to be closely associated with uveitis, including Vogt-Koyanagi-Harada disease and Behcet's disease, and is essential for maintaining the dynamic homeostasis of autoimmunity, its exact role in uveitis remains unclear. In this study, diminished EGR2 expression was observed in both retinal microglia from experimental autoimmune uveitis (EAU) mice and inflammation-induced human microglia cell line (HMC3). We constructed a mice model with conditional knockout of EGR2 in microglia and found that EGR2 deficiency resulted in increased intraocular inflammation. Meanwhile, EGR2 overexpression downregulated the expression of inflammatory cytokines as well as cell migration and proliferation in HMC3 cells. Next, RNA sequencing and ChIP-PCR results indicated that EGR2 directly bound to its downstream target growth differentiation factor 15 (GDF15) and further regulated GDF15 transcription. Furthermore, intravitreal injection of GDF15 recombinant protein was shown to ameliorate EAU progression in vivo. Meanwhile, knockdown of GDF15 reversed the phenotype of EGR2 overexpression-induced microglial inflammation in vitro. In summary, this study highlighted the protective role of the transcription factor EGR2 in AU by modulating the microglial phenotype. GFD15 was identified as a downstream target of EGR2, providing a unique target for uveitis treatment.

Heart Failure Risk Assessment Using Biomarkers in Patients With Atrial Fibrillation: Analysis From COMBINE-AF.

BACKGROUND: Heart failure (HF) is common among patients with atrial fibrillation (AF), and accurate risk assessment is clinically important. OBJECTIVES: The goal of this study was to investigate the incremental prognostic performance of N-terminal pro-B-type natriuretic peptide (NT-proBNP), high-sensitivity cardiac troponin T (hs-cTnT), and growth differentiation factor (GDF)-15 for HF risk stratification in patients with AF. METHODS: Individual patient data from 3 large randomized trials comparing direct oral anticoagulants (DOACs) with warfarin (ARISTOTLE [Apixaban for Reduction in Stroke and Other Thromboembolic Events in Atrial Fibrillation], ENGAGE AF-TIMI 48 [Effective Anticoagulation With Factor Xa Next Generation in Atrial Fibrillation-Thrombolysis In Myocardial Infarction 48], and RE-LY [Randomized Evaluation of Long-Term Anticoagulation Therapy]) from the COMBINE-AF (A Collaboration Between Multiple Institutions to Better Investigate Non-Vitamin K Antagonist Oral Anticoagulant Use in Atrial Fibrillation) cohort were pooled; all patients with available biomarkers at baseline were included. The composite endpoint was hospitalization for HF (HHF) or cardiovascular death (CVD), and secondary endpoints were HHF and HF-related death. Cox regression was used, adjusting for clinical factors, and interbiomarker correlation was addressed using weighted quantile sum regression analysis. RESULTS: In 32,041 patients, higher biomarker values were associated with a graded increase in absolute risk for CVD/HHF, HHF, and HF-related death. Adjusting for clinical variables and all biomarkers, NT-proBNP (HR per 1 SD: 1.68; 95% CI: 1.59-1.77), hs-cTnT (HR: 1.39; 95% CI: 1.33-1.44), and GDF-15 (HR: 1.20; 95% CI: 1.15-1.25) were significantly associated with CVD/HHF. The discrimination of the clinical model improved significantly upon addition of the biomarkers (c-index: 0.70 [95% CI: 0.69-0.71] to 0.77 [95% CI: 0.76-0.78]; likelihood ratio test, P < 0.001). Using weighted quantile sum regression analysis, the contribution to risk assessment was similar for NT-proBNP and hs-cTnT for CVD/HHF (38% and 41%, respectively); GDF-15 provided a statistically significant but lesser contribution to risk assessment. Results were similar for HHF and HF-related death, individually, and across key subgroups of patients based on a history of HF, AF pattern, and reduced or preserved left ventricular ejection fraction. CONCLUSIONS: NT-proBNP, hs-cTnT, and GDF-15 contributed significantly and independently to the risk stratification for HF endpoints in patients with AF, with hs-cTnT being as important as NT-proBNP for HF risk stratification. Our findings support a possible future use of these biomarkers to distinguish patients with AF at low or high risk for HF.

Biomarker-enhanced cardiovascular risk prediction in patients with cancer: a prospective cohort study.

BACKGROUND: Continuously improving cancer-specific survival puts a growing proportion of cancer patients at risk of major adverse cardiovascular events (MACE), but tailored tools for cardiovascular risk prediction remain unavailable. OBJECTIVES: To assess a broad panel of cardiovascular biomarkers and risk factors for the prediction of MACE and cardiovascular death in cancer patients. METHODS: In total, 2192 patients with newly diagnosed or recurrent cancer were followed prospectively for the occurrence of 2-year MACE and 5-year cardiovascular death. Univariable and multivariable risk models were fit to assess independent associations of cardiovascular risk factors and biomarkers with adverse outcomes, and a risk score was developed. RESULTS: Traditional cardiovascular risk factors and selected cancer types were linked to higher MACE risk. While levels of Lp(a), CRP, and GDF-15 did not associate with MACE, levels of ICAM-1, P-/E-/L-selectins, and NT-proBNP were independently linked to 2-year MACE risk. A clinical risk score was derived, assigning +1 point for male sex, smoking, and age of ≥60 years and +2 points for atherosclerotic disease, yielding a bootstrapped C-statistic of 0.76 (95% CI: 0.71-0.81) for the prediction of 2-year MACE. Implementation of biomarker data conferred improved performance (0.83, 95% CI: 0.78-0.88), with a simplified model showing similar performance (0.80, 95% CI: 0.74-0.86). The biomarker-enhanced and simplified prediction models achieved a C-statistic of 0.82 (95% CI: 0.71-0.93) and 0.74 (95% CI: 0.64-0.83) for the prediction of 5-year cardiovascular death. CONCLUSION: Biomarker-enhanced risk prediction strategies allow the identification of cancer patients at high risk of MACE and cardiovascular death. While external validation studies are ongoing, this first-of-its-kind risk score may provide the basis for personalized cardiovascular risk assessment across cancer entities.

Identification and characterization of human GDF15 knockouts.

Growth differentiation factor 15 (GDF15) is a secreted protein that regulates food intake, body weight and stress responses in pre-clinical models1. The physiological function of GDF15 in humans remains unclear. Pharmacologically, GDF15 agonism in humans causes nausea without accompanying weight loss2, and GDF15 antagonism is being tested in clinical trials to treat cachexia and anorexia. Human genetics point to a role for GDF15 in hyperemesis gravidarum, but the safety or impact of complete GDF15 loss, particularly during pregnancy, is unknown3-7. Here we show the absence of an overt phenotype in human GDF15 loss-of-function carriers, including stop gains, frameshifts and the fully inactivating missense variant C211G3. These individuals were identified from 75,018 whole-exome/genome-sequenced participants in the Pakistan Genomic Resource8,9 and recall-by-genotype studies with family-based recruitment of variant carrier probands. We describe 8 homozygous ('knockouts') and 227 heterozygous carriers of loss-of-function alleles, including C211G. GDF15 knockouts range in age from 31 to 75 years, are fertile, have multiple children and show no consistent overt phenotypes, including metabolic dysfunction. Our data support the hypothesis that GDF15 is not required for fertility, healthy pregnancy, foetal development or survival into adulthood. These observations support the safety of therapeutics that block GDF15.

The MondoA-dependent TXNIP/GDF15 axis predicts oxaliplatin response in colorectal adenocarcinomas.

Chemotherapy, the standard of care treatment for cancer patients with advanced disease, has been increasingly recognized to activate host immune responses to produce durable outcomes. Here, in colorectal adenocarcinoma (CRC) we identify oxaliplatin-induced Thioredoxin-Interacting Protein (TXNIP), a MondoA-dependent tumor suppressor gene, as a negative regulator of Growth/Differentiation Factor 15 (GDF15). GDF15 is a negative prognostic factor in CRC and promotes the differentiation of regulatory T cells (Tregs), which inhibit CD8 T-cell activation. Intriguingly, multiple models including patient-derived tumor organoids demonstrate that the loss of TXNIP and GDF15 responsiveness to oxaliplatin is associated with advanced disease or chemotherapeutic resistance, with transcriptomic or proteomic GDF15/TXNIP ratios showing potential as a prognostic biomarker. These findings illustrate a potentially common pathway where chemotherapy-induced epithelial oxidative stress drives local immune remodeling for patient benefit, with disruption of this pathway seen in refractory or advanced cases.

METTL14-Mediated m6A Modification of TUG1 Represses Ferroptosis in Alzheimer's Disease via Inhibiting GDF15 Ubiquitination.

BACKGROUND: Alzheimer's disease (AD) is a neurodegenerative disease that remains a serious global health issue. Ferroptosis has been recognized as a vital driver of pathological progression of AD. However, the detailed regulatory mechanisms of ferroptosis during AD progression remain unclear. This study aimed to explore the regulatory role and mechanism of methyltransferase like 14 (METTL14) in ferroptosis in AD models. METHODS: Serum samples were collected from 18 AD patients and 18 healthy volunteers to evaluate clinical correlation. Scopolamine-treated mice and Aß1-42-stimulated SH-SY5Y cells were served as the in vivo and in vitro models of AD. Ferroptosis was detected by reactive oxygen species (ROS), Fe2+, total iron levels, and ferroptosis-related proteins glutathione peroxidase 4 (GPX4) and solute carrier family 7 member 11 (SLC7A11). Cell viability was analyzed by 3-(4,5-dimethylthiazol-2-yl)-2,5 diphenyltetrazolium bromide (MTT) assay. The N6-methyladenosine (m6A) modification was detected by RNA methylation quantification kit and methylated RNA immunoprecipitation sequencing-quantitative real-time polymerase chain reaction (MeRIP-qPCR). Molecular mechanisms were investigated by RNA pull-down, RNA immunoprecipitation (RIP), and co-immunoprecipitation (Co-IP) assays. Cognitive disorder of AD mice was measured by Morris water maze test. RESULTS: METTL14 was down-regulated, while lncRNA taurine upregulated gene 1 (TUG1) was up-regulated in clinical patients and experimental models of AD. Functional experiments demonstrated that METTL14 overexpression or TUG1 silencing effectively attenuated Aß1-42-induced ferroptosis and neurotoxicity in SH-SY5Y cells. Mechanistically, METTL14-mediated m6A modification reduced the stability of TUG1. Moreover, TUG1 promoted the ubiquitination and degradation of growth differentiation factor 15 (GDF15) by directly interacted with Smad ubiquitin regulatory factor 1 (SMURF1), which consequently inactivated nuclear factor erythroid 2-related factor 2 (NRF2). Rescue experiments indicated that GDF15 depletion reversed sh-TUG1-mediated protection against ferroptosis and neurotoxicity. Finally, Mettl14 overexpression repressed ferroptosis to ameliorate the cognitive disorder via modulating Tug1/Gdf15/Nrf2 pathway in vivo. CONCLUSION: METTL14 inhibited ferroptosis to ameliorate AD pathological development by m6A modification of TUG1 to activate GDF15/NRF2 axis, providing a novel therapeutic target for AD.

GDF11 (Protein of Juvenility) and GDF15 (Protein of Senility) in the Plasma of Patients with Sleep Apnea Syndrome: a Pilot Study.

We performed a matched-pair analysis of the content of GDF11 and GDF15 proteins in the plasma of patients (56 middle-aged men) with obstructive sleep apnea syndrome (OSAS) and healthy volunteers (27 men with no complaints of sleep disorders). The groups were comparable in terms of age and presence of chronic diseases. No statistically significant differences in GDF11 content in the studied groups were revealed, while the content of GDF15 in the OSAS group was 1.3 times higher. These results require further research from the viewpoint of geriatric somnology and molecular biology.

Bitter-tasting drugs tune GDF15 and GLP-1 expression via bitter taste or motilin receptors in the intestine of patients with obesity.

OBJECTIVE: Growth differentiation factor 15 (GDF15), a stress related cytokine, was recently identified as a novel satiety signal acting via the GFRAL receptor located in the hindbrain. Bitter compounds are known to induce satiety via the release of glucagon-like peptide 1 (GLP-1) through activation of bitter taste receptors (TAS2Rs, 25 subtypes) on enteroendocrine cells in the gut. This study aimed to investigate whether and how bitter compounds induce a stress response in intestinal epithelial cells to affect GDF15 expression in patients with obesity, thereby facilitating satiety signaling from the gut. METHODS: The acute effect of oral intake of the bitter-containing medication Plaquenil (hydroxychloroquine sulfate) on plasma GDF15 levels was evaluated in a placebo-controlled, double-blind, randomized, two-visit crossover study in healthy volunteers. Primary crypts isolated from the jejunal mucosa from patients with obesity were stimulated with vehicle or bitter compounds, and the effect on GDF15 expression was evaluated using RT-qPCR or ELISA. Immunofluorescence colocalization studies were performed between GDF15, epithelial cell type markers and TAS2Rs. The role of TAS2Rs was tested by 1) pretreatment with a TAS2R antagonist, GIV3727; 2) determining TAS2R4/43 polymorphisms that affect taste sensitivity to TAS2R4/43 agonists. RESULTS: Acute intake of hydroxychloroquine sulfate increased GDF15 plasma levels, which correlated with reduced hunger scores and plasma ghrelin levels in healthy volunteers. This effect was mimicked in primary jejunal cultures from patients with obesity. GDF15 was expressed in enteroendocrine and goblet cells with higher expression levels in patients with obesity. Various bitter-tasting compounds (medicinal, plant extracts, bacterial) either increased or decreased GDF15 expression, with some also affecting GLP-1. The effect was mediated by specific intestinal TAS2R subtypes and the unfolded protein response pathway. The bitter-induced effect on GDF15/GLP-1 expression was influenced by the existence of TAS2R4 amino acid polymorphisms and TAS2R43 deletion polymorphisms that may predict patient's therapeutic responsiveness. However, the effect of the bitter-tasting antibiotic azithromycin on GDF15 release was mediated via the motilin receptor, possibly explaining some of its aversive side effects. CONCLUSIONS: Bitter chemosensory and pharmacological receptors regulate the release of GDF15 from human gut epithelial cells and represent potential targets for modulating metabolic disorders or cachexia.