Our data suggest a myocardial protective effect of ALDH2 against I/R injury possibly through detoxification of toxic aldehyde and a differential regulation of autophagy through AMPK- and Akt-mTOR signalling during ischaemia and reperfusion, respectively.

Intellectual and motor development of children at 25-30 months of age is separately associated with abnormalities of maternal thyroid at 16-20 weeks gestation. Maternal subclinical hypothyroidism, hypothyroxinaemia or euthyroidism with elevated TPOAb titres were all statistically significant predictors of lower motor and intellectual development at 25-30 months.

SUMMARY Histone methylation occurs on both lysine and arginine residues, and its dynamic regulation plays a critical role in chromatin biology. Here we identify the UHRF1 PHD finger (PHDUHRF1), an important regulator of DNA CpG methylation, as a histone H3 unmodified arginine 2 (H3R2) recognition modality. This conclusion is based on binding studies and cocrystal structures of PHDUHRF1 bound to histone H3 peptides, where the guanidinium group of unmodified R2 forms an extensive intermolecular hydrogen bond network, with methylation of H3R2, but not H3K4 or H3K9, disrupting complex formation. We have identified direct target genes of UHRF1 from microarray and ChIP studies. Importantly, we show that UHRF1's ability to repress its direct target gene expression is dependent on PHDUHRF1 binding to unmodified H3R2, thereby demonstrating the functional importance of this recognition event and supporting the potential for crosstalk between histone arginine methylation and UHRF1 function.

SUMMARY BS69 (aka ZMYND11) contains tandemly arranged PHD, BROMO and PWWP domains, which are chromatin recognition modalities. Here we show that BS69 selectively recognizes histone variant H3.3 lysine 36 trimethylation (H3.3K36me3) via its chromatin-binding domains. We further identify BS69 association with RNA splicing regulators including the U5 snRNP components of the spliceosome such as EFTUD2. Remarkably, RNA-seq shows that BS69 mainly regulates intron retention (IR), which is the least well-understood RNA alternative splicing event in mammalian cells. Biochemical and genetic experiments demonstrate that BS69 promotes IR by antagonizing EFTUD2 through physical interactions. We further show that regulation of IR by BS69 also depends on its binding to H3K36me3-decorated chromatin. Taken together, our study identifies an H3.3K36me3-specific reader and a regulator of IR, and reveals a novel and unexpected role of BS69 in connecting histone H3.3K36me3 to regulated RNA splicing, providing significant new insights into chromatin regulation of pre-mRNA processing.

Summary Regulation of enhancer activity is important for controlling gene expression programs. Here we report that a biochemical complex that contains a potential chromatin reader, RACK7 and the histone lysine 4 tri-methyl (H3K4me3)-specific demethylase KDM5C occupies many active enhancers, including almost all super-enhancers. Loss of RACK7 or KDM5C results in overactivation of enhancers, characterized by the deposition of H3K4me3 and H3K27Ac, together with increased transcription of eRNAs and nearby genes. Furthermore, loss of RACK7 or KDM5C leads to de-repression of S100A oncogenes and various cancer-related phenotypes. Our findings reveal a RACK7/KDM5C-regulated, dynamic interchange between histone H3K4me1 and H3K4me3 at active enhancers, representing an additional layer of regulation of enhancer activity. We propose that RACK7/KDM5C functions as an enhancer “brake” to ensure appropriate enhancer activity, which, when compromised, could contribute to tumorigenesis.

UHRF1 (Ubiquitin-like, with PHD and RING finger domains 1) plays an important role in DNA CpG methylation, heterochromatin function and gene expression. Overexpression of UHRF1 has been suggested to contribute to tumorigenesis. However, regulation of UHRF1 is largely unknown. Here we show that the deubiquitylase USP7 interacts with UHRF1. Using interaction-defective and catalytic mutants of USP7 for complementation experiments, we demonstrate that both physical interaction and catalytic activity of USP7 are necessary for UHRF1 ubiquitylation and stability regulation. Mass spectrometry analysis identified phosphorylation of serine (S) 652 within the USP7-interacting domain of UHRF1, which was further confirmed by a UHRF1 S652 phosphor (S652ph)-specific antibody. Importantly, the S652ph antibody identifies phosphorylated UHRF1 in mitotic cells and consistently S652 can be phosphorylated by the M phase-specific kinase CDK1-cyclin B in vitro. UHRF1 S652 phosphorylation significantly reduces UHRF1 interaction with USP7 in vitro and in vivo, which is correlated with a decreased UHRF1 stability in the M phase of the cell cycle. In contrast, UHRF1 carrying the S652A mutation, which renders UHRF1 resistant to phosphorylation at S652, is more stable. Importantly, cells carrying the S652A mutant grow more slowly suggesting that maintaining an appropriate level of UHRF1 is important for cell proliferation regulation. Taken together, our findings uncovered a cell cycle-specific signaling event that relieves UHRF1 from its interaction with USP7, thus exposing UHRF1 to proteasome-mediated degradation. These findings identify a molecular mechanism by which cellular UHRF1 level is regulated, which may impact cell proliferation.deubiquitination | phosphorylation UHRF1 S652 E pigenetic regulation has emerged as an important mechanism that regulates many chromatin template-based processes, including transcription, DNA replication, and repair. An important component of epigenetic regulation is DNA CpG methylation, which is mediated by DNA methyltransferases such as DMNT1 and DNMT3a/b and an accessory factor DNMT3L (1, 2). Recent studies demonstrate that maintenance of DNA methylation patterns requires UHRF1 (Ubiquitin-like, with PHD and RING finger domains 1) (also called Np95 and ICBP90). UHRF1 binds hemimethylated CpG and recruits DNMT1 to ensure faithful propagation of the DNA methylation patterns through DNA replication (3, 4). UHRF1 is also localized to euchromatic regions where it regulates transcription possibly by impacting DNA methylation and histone modifications (5, 6). UHRF1 has been shown to regulate cell proliferation, and its loss has been implicated in the mis-regulation of both G1 and G2/M phases of the cell cycle, respectively (7). However, very little is known how this important epigenetic regulator itself is regulated. To address this question, we have recently undertaken a proteomics approach and identified a cell cycle signaling-regulated physical interaction of UHRF1 with the deubiquitylase USP7 (HAUSP) (8,9) ...

Adiponectin (APN), an adipose-derived adipokine, offers cardioprotective effects although the precise mechanism of action remains unclear. This study was designed to examine the role of APN in high fat diet-induced obesity and cardiac pathology. Adult C57BL/6 wild-type and APN knockout mice were fed a low or high fat diet for 22 weeks. After 40 day feeding, mice were treated with 2 mg/kg rapamycin or vehicle every other day for 42 days on respective fat diet. Cardiomyocyte contractile and Ca2+ transient properties were evaluated. Myocardial function was evaluated using echocardiography. Dual energy X-ray absorptiometry was used to evaluate adiposity. Energy expenditure, metabolic rate and physical activity were monitored using a metabolic cage. Lipid deposition, serum triglyceride, glucose tolerance, markers of autophagy and fatty acid metabolism including LC3, p62, Beclin-1, AMPK, mTOR, fatty acid synthase (FAS) were evaluated. High fat diet intake induced obesity, systemic glucose intolerance, cardiac hypertrophy, dampened metabolic ability, cardiac and intracellular Ca2+ derangements, the effects of which were accentuated by APN knockout. Furthermore, APN deficiency augmented high fat diet-induced upregulation in the autophagy adaptor p62 and the decline in AMPK without affecting high fat diet-induced decrease in LC3II and LC3II-to-LC3I ratio. Neither high fat diet nor APN deficiency altered Beclin-1. Interestingly, rapamycin negated high fat diet-induced/APN-deficiency-accentuated obesity, cardiac hypertrophy and contractile dysfunction as well as AMPK dephosphorylation, mTOR phosphorylation and p62 buildup. Our results collectively revealed that APN deficiency may aggravate high fat diet-induced obesity, metabolic derangement, cardiac hypertrophy and contractile dysfunction possibly through decreased myocardial autophagy.

Breast cancer susceptibility gene II (BRCA2) is central in homologous recombination (HR). In meiosis, BRCA2 binds to MEILB2 to localize to DNA double-strand breaks (DSBs). Here, we identify BRCA2 and MEILB2-associating protein 1 (BRME1), which functions as a stabilizer of MEILB2 by binding to an α-helical N-terminus of MEILB2 and preventing MEILB2 selfassociation. BRCA2 binds to the C-terminus of MEILB2, resulting in the formation of the BRCA2-MEILB2-BRME1 ternary complex. In Brme1 knockout (Brme1 −/−) mice, the BRCA2-MEILB2 complex is destabilized, leading to defects in DSB repair, homolog synapsis, and crossover formation. Persistent DSBs in Brme1 −/− reactivate the somatic-like DNA-damage response, which repairs DSBs but cannot complement the crossover formation defects. Further, MEILB2-BRME1 is activated in many human cancers, and somatically expressed MEILB2-BRME1 impairs mitotic HR. Thus, the meiotic BRCA2 complex is central in meiotic HR, and its misregulation is implicated in cancer development.