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Biology subjects

Oeing, C. U.

Publications and source records attributed to Oeing, C. U..

5 recordsLinked to original sources

Selective class IIa HDAC inhibition reverses diastolic dysfunction in cardiometabolic HFpEF

Heart failure with preserved ejection fraction (HFpEF) is a highly prevalent cardiometabolic syndrome with yet no effective therapies. Here, we report that selectively class IIa histone deacetylases (HDACs) but no other classes of HDACs are enzymatically activated in hearts from HFpEF patients and cardiometabolic HFpEF animal models. Cell type-specific and enzymatic activity-specific genetic loss-of-function models of the cardiomyocyte-enriched class IIa HDAC family member HDAC4 and the pharmacological class IIa HDAC-selective inhibitor TMP195 prevent and reverse diastolic dysfunction and exercise intolerance in cardiometabolic HFpEF in vivo. In contrast to pan-HDAC inhibition no adverse effects are observed. Despite its well-known non-enzymatic role as transcriptional repressor, we found that specifically enzymatic activation of HDAC4 has little direct effects on cardiomyocyte-intrinsic gene expression. Instead, non-epigenetic actions lead to endothelial activation via altered cardiocrine signaling. We discovered that selective enzymatic class IIa HDAC inhibition is a new therapeutic concept to combat cardiac HFpEF.

molecular biology↗

Genomic G quadruplexes regulate mRNA splicing

Genomic G quadruplexes (G4) are non-canonical DNA structures that regulate gene expression primarily through transcriptional control. Here, we uncover that DNA G quadruplexes are critical determinants of pre-mRNA splicing. G4s on the DNA template strand serve as recruiting elements for the RNA-binding proteins SRSF9 and WBP11 in order to facilitate productive splicing of adjacent pre-mRNAs. This process is controlled by protein arginine methyltransferase 5 (PRMT5) that releases SRSF9 and WBP11 from G4s through arginine methylation. Acyl-CoA dehydrogenase very long-chain specific (ACADVL) is a gene highly regulated by this mechanism since targeting G4 stability prevents mis-splicing and restores ACADVL protein levels. In the heart, deletion of Prmt5 recapitulates defective splicing and results in progressive cardiac failure along with loss of ACADVL in mice. Importantly, we find that Acadvl regulation plays a critical role for cardiomyopathy as restoring Acadvl expression in Prmt5 knockout mice prevents cardiac dysfunction. This study establishes an unanticipated fundamental principle by which genomic G quadruplexes act as splicing enhancers of associated pre-mRNAs, and reveals an essential role in cardiac homeostasis.

cell biology↗

Male violence disrupts estrogen receptor β signaling in the female hippocampus

Women are the main target of intimate partner violence (IPV), which is escalating worldwide. Mechanisms subtending IPV-related disorders, such as anxiety, depression and PTSD, remain unclear. We employed a mouse model molded on an IPV scenario (male vs. female prolonged violent interaction) to unearth the neuroendocrine alterations triggered by an aggressive male mouse on the female murine brain. Experimental IPV (EIPV) prompted marked anxiety-like behavior in young female mice, coincident with high circulating/cerebral corticosterone levels. The hippocampus of EIPV-inflicted female animals displayed neuronal loss, reduced BrdU-DCX-positive nuclei, decreased mature DCX-positive cells, and diminished dendritic arborization level in the dentate gyrus (DG), features denoting impaired neurogenesis and neuronal differentiation. These hallmarks were associated with marked down-regulation of estrogen receptor {beta} (ER{beta}) density in the hippocampus, especially in the DG and dependent prosurvival ERK signaling. Conversely, ER expression was unchanged. After EIPV, the DG harbored lowered local BDNF pools, diminished TrkB phosphorylation, and elevated glucocorticoid receptor phosphorylation. In unison, ER{beta} KO mice had heightened anxiety-like behavior and curtailed BDNF levels at baseline, despite enhanced circulating estradiol levels, while dying prematurely during EIPV. Thus, reiterated male-to-female violence jeopardizes hippocampal homeostasis in the female brain, perturbing ER{beta}/BDNF signaling, thus instigating anxiety and chronic stress.

neuroscience↗

Single Serine on TSC2 Exerts Biased Control over mTORC1 Activation by ERK1/2 but Not Akt

The mammalian target of rapamycin complex 1 (mTORC1) is tightly controlled by tuberous sclerosis complex-2 (TSC2) that is regulated by phosphorylation from kinases responding to environmental cues. Protein kinase G specifically modifies serine-1365 (S1364, human), and its phosphorylation (or phosphomimetic SE mutant) potently blocks mTORC1 co-activation by pathological stress, while a phospho-silenced (SA) mutation does the opposite. Neither alter basal mTORC1 activity. Here we show S1365 exerts biased control over mTORC1 activity (S6K phosphorylation) modifying ERK1/2 but not Akt-dependent stimulation. Whereas mTORC1 activation by endothelin-1 is potently modified by S1365 status, insulin or PDGF stimulation are unaltered. TSC2-S1365 is also phosphorylated upon ET-1 but not insulin stimulation in a PKG-dependent manner, revealing intrinsic bias. Neither energy or nutrient modulation of mTORC1 are impacted by S1365. Consistent with these results, knock-in mice with either TSC2 SA or SE mutations develop identical obesity, glucose intolerance, and fatty liver disease from a high fat diet. Thus, S1365 provides an ERK1/2-selective mTORC1 control mechanism and a genetic means to modify pathological versus physiological mTOR stimuli.

cell biology↗

PDE9 Inhibition Activates PPARa to Stimulate Mitochondrial Fat Metabolism and Reduce Cardiometabolic Syndrome

Central obesity with cardiometabolic syndrome (CMS) is a major global contributor to human disease, and effective therapies are needed. Here, we show inhibiting cyclic-GMP selective phosphodiesterase-9A (PDE9-I) suppresses established diet-induced obesity and CMS in ovariectomized female and male mice. PDE9-I reduces abdominal, hepatic, and myocardial fat accumulation, stimulates mitochondrial activity in brown and white fat, and improves CMS, without altering activity or food intake. PDE9 localizes to mitochondria, and its inhibition stimulates lipolysis and mitochondrial respiration coupled to PPAR-dependent gene regulation. PPAR upregulation is required for PDE9-I metabolic efficacy and is absent in non-ovariectomized females that also display no metabolic benefits from PDE9-I. The latter is compatible with estrogen receptor- altering PPAR chromatin binding identified by ChIPSeq. In humans with heart failure and preserved ejection fraction, myocardial expression of PPARA and its regulated genes is reduced versus control. These findings support testing PDE9-I to treat obesity/CMS in men and postmenopausal women. SummaryOral inhibition of phosphodiesterase type 9 stimulates mitochondrial fat metabolism and lipolysis, reducing central obesity without changing appetite

physiology↗