Biology subjects

Bundo, M.

Publications and source records attributed to Bundo, M..

6 recordsLinked to original sources

bioRxiv2026

Hepatic Ketogenesis Attenuates Cardiac Hypertrophy via Metabolic Reprogramming

BackgroundHeart failure with preserved ejection fraction (HfpEF) is increasingly recognized as a multisystem disorder linked to the cardiovascular-kidney-metabolic (CKM) syndrome. While the falling heart undergoes metabolic reprogramming, the interorgan crosstalk regulating myocardial substrate preference in HFpEF remains elusive. We aimed to clarify the role of systemic and local ketogenesis in the pathogenesis of cardiac hypertrophy and HFpEF. MethodsA mouse model of HFpEF was employed using a high-fat diet combined with NG-Nitro-L-arginine methyl ester hydrochloride (L-NAME). Cardiac hypertrophy and systemic metabolic profiling including ketogenesis were evaluated. To dissect the role of site-specific ketogenesis, we generated inducible cardiomyocyte-specific (Hmgcs2{Delta}iCM) and hepatocyte-specific (Hmgcs2{Delta}Hep) knockout mice of HMG-CoA synthase 2 (Hmgcs2), deficient in the rate-limiting enzyme for ketogenesis. Cardiomyocyte -specific nuclei were isolated for transcriptomic (RNA-seq) and in vitro assays in H9C2 cells were used to elucidate molecular mechanisms. ResultsThe HFpEF model successfully exhibited diastolic dysfunction, impaired exercise capacity and cardiac hypertrophy with elevated circulating ketone body concentration. Myocardial metabolomics and snRNA-seq identified a profound metabolic shift characterized by the accumulation of long-chain fatty acids and Krebs cycle intermediates, coupled with the transcriptional downregulation of insulin signaling and fatty acid degradation pathways. Although circulating ketone body level was upregulated, Hmgcs2{Delta}iCM mice showed no exacerbation of the HFpEF phenotype. In contrast, Hmgcs2{Delta}Hep mice exhibited significantly aggravated cardiac hypertrophy (HW/TL; Hmgcs2flox: 7.41 {+/-} 0.87: Hmgcs2{Delta}Hep: 8.29 {+/-} 0.73; p = 0.0154). Mechanistically, hepatic ketogenesis was required to maintain circulating beta-hydroxybutyrate (BHB) levels, which directly modulated cardiomyocyte metabolism. BHB acted as a metabolic signal to dampen fatty acid overload and facilitate glucose utilization. ConclusionsOur study identifies a critical "liver-heart axis" where hepatic ketogenesis serves as an essential regulator of myocardial metabolic resilience. Impaired hepatic ketogenesis creates a metabolic mismatch that drives pathological cardiac remodeling. These findings highlight the liver as a therapeutic target within the CKM syndrome framework, suggesting that restoring the hepato-cardiac metabolic bridge may ameliorate HFpEF progression. What is New?O_LIThis study identifies a novel liver-adipose-heart axis that governs myocardial metabolic resilience during the development of heart failure with preserved ejection fraction (HFpEF). C_LIO_LIWe demonstrate that while both the liver and heart upregulate ketogenesis under metabolic stress, only hepatic ketogenesis--and not cardiac-intrinsic ketogenesis--is essential for mitigating pathological cardiac remodeling. C_LIO_LIMechanistically, liver-derived {beta} -hydroxybutyrate acts as a critical C_LIO_LIendocrine signal that dampens fatty acid oxidation and facilitates myocardial glucose utilization. C_LI What Are the Clinical Implications?O_LIOur findings highlight the liver as a central therapeutic target within the cardiovascular-kidney-metabolic (CKM) syndrome framework, where hepatic metabolic failure directly drives cardiac dysfunction. C_LIO_LIRestoring the hepato-cardiac metabolic bridge, through either hepatic-targeted therapies or ketone body supplementation, represents a promising strategy to enhance myocardial metabolic flexibility and ameliorate HfpEF in patients with multi-organ metabolic disorders. C_LI

biochemistry↗

bioRxiv2026

Molecular basis of delayed leaf senescence induced by short-term treatment with low phosphate in rice

Leaf senescence is a programmed plant developmental process that can also be regulated by environmental factors, like nutrient availability. Although phosphorus is an essential element determining plants growth and productivity, mechanisms underlying adaptation to phosphorus availability in plants are not well understood. In this study, we combined physiological, biochemical and molecular approaches to investigate the effect of phosphate supply on leaf senescence in rice. We show that short-term treatment of rice seedlings with low phosphate increases photosynthetic pigments content, confers tolerance to methyl viologen-induced oxidative stress in chloroplasts, and increases antioxidant enzyme activities. Leaves from low-Pi-treated plants also showed a reduction in membrane lipid peroxidation and electrolyte leakage. Opposite trends were observed in seedlings under high Pi supply, in which accelerated leaf senescence occurs. Further analyses indicated that CRISPR/Cas9-mediated editing of MIR827, and subsequent reduction in Pi content, promotes delayed leaf senescence, while Pi accumulation in MIR827 or MIR399 overexpressing plants accelerates senescence. These findings strongly support that short treatment with low phosphate delays rice leaf senescence. Transcriptomic analysis demonstrated multiple biological processes underlying adaptation of rice plants to low phosphate, including senescence-associated and metabolic processes. These findings provide novel insights into leaf senescence potentially contributing to sustainable rice production.

plant biology↗

bioRxiv2025

Genome-wide mapping of sex-associated autosomal DNA methylation in major blood cell types

Sex differences shape human physiology and disease risk, yet their autosomal epigenetic basis remains incompletely understood. Using whole genome bisulfite sequencing data from iMETHYL database ([~]100 adults) across three purified blood cell types (CD4 T cells, monocytes, neutrophils), we performed comprehensive mapping of cell-type specific sex-associated DNA methylation. Using genome-wide Z-test and confidence-interval method, we identified thousands of autosomal differentially methylated sites (DMSs), the majority of which were cell type-specific. We found that neutrophils exhibited pronounced female-biased hypermethylation, whereas CD4 T cells and monocytes showed more balanced patterns. DMSs were enriched within gene bodies and annotated to neuronal and adhesion functions, with T-cell activation uniquely associated in CD4 T cells. Transcription factor binding site enrichment indicated hematopoietic regulators, suggesting that sex-associated methylation is tightly linked to early developmental processes within blood lineages. Differentially methylated regions overlapped genome-wide association study loci for lifetime smoking, multiple sclerosis, and psoriasis, indicating convergence between sex-associated epigenetic states and genetic susceptibility. Evolutionary analysis revealed limited conservation but identified a conserved intronic CpG within FIGN. This study provides the first genome-wide, cell type-resolved map of autosomal sex-associated DNA methylation in human blood and establishes a foundation for mechanistic and translational studies in sex-informed biology and medicine. GRAPHICAL ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=79 SRC="FIGDIR/small/682299v1_ufig1.gif" ALT="Figure 1"> View larger version (30K): org.highwire.dtl.DTLVardef@18524c0org.highwire.dtl.DTLVardef@2fd8cdorg.highwire.dtl.DTLVardef@142b445org.highwire.dtl.DTLVardef@4949be_HPS_FORMAT_FIGEXP M_FIG C_FIG

genetics↗

bioRxiv2021

NITROGEN LIMITATION ADAPTATION functions as a negative regulator of Arabidopsis immunity

BackgroundPhosphorus is an important macronutrient required for plant growth and development. It is absorbed through the roots in the form of inorganic phosphate (Pi). To cope with Pi limitation, plants have evolved an array of adaptive mechanisms to facilitate Pi acquisition and protect them from stress caused by Pi starvation. The NITROGEN LIMITATION ADAPTION (NLA) gene plays a key role in the regulation of phosphate starvation responses (PSR), its expression being regulated by the microRNA miR827. Stress caused by Pi limiting conditions might also affect the plants response to pathogen infection. However, cross-talk between phosphate signaling pathways and immune responses remains unclear. ResultsIn this study, we investigated whether NLA plays a role in Arabidopsis immunity. We show that loss-of-function of NLA and MIR827 overexpression causes an increase in phosphate (Pi) content which results in resistance to infection by the fungal pathogen Plectosphaerella cucumerina. The nla mutant plants accumulated callose in their leaves, a response that is also observed in wild-type plants that have been treated with high Pi. We also show that pathogen infection and treatment with fungal elicitors is accompanied by transcriptional activation of MIR827 and down-regulation of NLA. Upon pathogen challenge, nla plants exhibited higher levels of the phytoalexin camalexin compared to wild type plants. Camalexin level also increases in wild type plants treated with high Pi. Furthermore, the nla mutant plants accumulated salicylic acid (SA) and jasmonic acid (JA) in the absence of pathogen infection whose levels further increased upon pathogen. ConclusionsThis study shows that NLA acts as a negative regulator of Arabidopsis immunity. Overaccumulation of Pi in nla plants positively affects resistance to infection by fungal pathogens. This piece of information reinforces the idea of signaling convergence between Pi and immune responses for the regulation of disease resistance in Arabidopsis.

plant biology↗

bioRxiv2021

Phosphate-induced resistance to pathogen infection in Arabidopsis

In nature, plants are concurrently exposed to a number of abiotic and biotic stresses. Our understanding of convergence points between responses to combined biotic/abiotic stress pathways remains, however, rudimentary. Here we show that MIR399 overexpression, loss-of-function of PHO2 (PHOSPHATE2), or treatment with high Pi, is accompanied by an increase in phosphate (Pi) content and accumulation of reactive oxygen species (ROS) in Arabidopsis thaliana. High Pi plants (e.g. miR399 overexpressor, pho2 mutant, and plants grown under high Pi supply) exhibited resistance to infection by necrotrophic and hemibiotrophic fungal pathogens. In the absence of pathogen infection, the expression level of genes in the salicylic acid (SA)- and jasmonic acid (JA)-dependent signaling pathways was higher in high Pi plants compared to wild type plants, which is consistent with increased levels of SA and JA in non-infected high Pi plants. During infection, an opposite regulation in the two branches of the JA pathway (ERF1/PDF1.2 and MYC2/VSP2) occurs in high Pi plants. Thus, while the ERF1-PDF1 branch positively responds to fungal infection, the MYC2/VSP2 branch is negatively regulated during pathogen infection in high Pi plants. This study supports that Pi accumulation promotes resistance to infection by fungal pathogens in Arabidopsis, while providing a basis to better understand crosstalk between Pi signaling and hormonal signalling pathways for modulation of plant immune responses. Significance statementThis study highlights the importance of phosphate (Pi) in regulating immune responses, hence, disease resistance in Arabidopsis thaliana. Increasing Pi content either by MIR399 overexpression (or loss-of-function of PHOSPHATE2), as well as by Pi treatment enhances resistance to infection by necrotrophic and hemibiotrophic fungal pathogens through modulation of SA- and JA-dependent signaling pathways. These results also support that miR399 functions as a regulator of Arabidopsis immunity.

plant biology↗

bioRxiv2020

Promoter activity-based case-control association study on SLC6A4 highlighting hypermethylation and altered amygdala volume in male patients with schizophrenia

Associations between altered DNA methylation of the serotonin transporter (5-HTT)-encoding gene SLC6A4 and early life adversity, mood and anxiety disorders, and amygdala reactivity have been reported. However, few studies have examined epigenetic alterations of SLC6A4 in schizophrenia (SZ). We examined CpG sites of SLC6A4, whose DNA methylation levels have been reported to be altered in bipolar disorder, using three independent cohorts of patients with SZ and age-matched controls. We found significant hypermethylation of a CpG site in SLC6A4 in male patients with SZ in all three cohorts. We showed that chronic administration of risperidone did not affect the DNA methylation status at this CpG site using common marmosets, and that in vitro DNA methylation at this CpG site diminished the promoter activity of SLC6A4. We then genotyped the 5-HTT-linked polymorphic region (5-HTTLPR) and investigated the relationship among 5-HTTLPR, DNA methylation, and amygdala volume using brain imaging data. We found that patients harboring low-activity 5-HTTLPR alleles showed hypermethylation and they showed a negative correlation between DNA methylation levels and left amygdala volumes. These results suggest that hypermethylation of the CpG site in SLC6A4 is involved in the pathophysiology of SZ, especially in male patients harboring low-activity 5-HTTLPR alleles.

genetics↗