Modifications of small RNAs and their associated proteins.

Small regulatory RNAs and their associated proteins are subject to diverse modifications that can impinge on their abundance and function. Some of the modifications are under the influence of cellular signaling, thus contributing to the dynamic regulation of RNA silencing.

TUT4 in concert with Lin28 suppresses microRNA biogenesis through pre-microRNA uridylation.

As key regulators in cellular functions, microRNAs (miRNAs) themselves need to be tightly controlled. Lin28, a pluripotency factor, was reported to downregulate let-7 miRNA by inducing uridylation of let-7 precursor (pre-let-7). But the enzyme responsible for the uridylation remained unknown. Here we identify a noncanonical poly (A) polymerase, TUTase4 (TUT4), as the uridylyl transferase for pre-let-7. Lin28 recruits TUT4 to pre-let-7 by recognizing a tetra-nucleotide sequence motif (GGAG) in the terminal loop. TUT4 in turn adds an oligouridine tail to the pre-let-7, which blocks Dicer processing. Other miRNAs with the same sequence motif (miR-107, -143, and -200c) are regulated through the same mechanism. Knockdown of TUT4 and Lin28 reduces the level of stem cell markers, suggesting that they are required for stem cell maintenance. This study uncovers the role of TUT4 and Lin28 as specific suppressors of miRNA biogenesis, which has implications for stem cell research and cancer biology.

Posttranscriptional crossregulation between Drosha and DGCR8.

The Drosha-DGCR8 complex, also known as Microprocessor, is essential for microRNA (miRNA) maturation. Drosha functions as the catalytic subunit, while DGCR8 (also known as Pasha) recognizes the RNA substrate. Although the action mechanism of this complex has been intensively studied, it remains unclear how Drosha and DGCR8 are regulated and if these proteins have any additional role(s) apart from miRNA processing. Here, we report that Drosha and DGCR8 regulate each other posttranscriptionally. The Drosha-DGCR8 complex cleaves the hairpin structures embedded in the DGCR8 mRNA and thereby destabilizes the mRNA. We further find that DGCR8 stabilizes the Drosha protein via protein-protein interaction. This crossregulation between Drosha and DGCR8 may contribute to the homeostatic control of miRNA biogenesis. Furthermore, microarray analyses suggest that a number of mRNAs may be downregulated in a Microprocessor-dependent, miRNA-independent manner. Our study reveals a previously unsuspected function of Microprocessor in mRNA stability control.

Investigating the link between antipsychotic use and post-stroke infections in older people: multi-centre propensity score analysis.

BACKGROUND: The risk of stroke increases with age, and although previous reports have suggested that infection risk may increase with antipsychotic use, relevant studies after stroke are scarce. We aimed to investigate whether antipsychotics increase post-stroke infection risk in the acute stroke period. METHODS: This propensity score matching study included adults diagnosed with first-ever stroke between 2011 and 2020 at five university hospitals. In-hospital antipsychotic exposure was defined as any administration during hospitalisation for stroke. The primary outcome was post-stroke infection after the first 2 days of hospitalisation, and the secondary outcome was the presence of pneumonia, bacteraemia and/or bacteriuria. RESULT: Among 23,885 first-ever stroke patients, 2,773 antipsychotic users (age 71.6 ± 12.4, male 54.6%) and 2,773 non-users (age 71.2 ± 13.2, male 54.6%) were selected as matched cohorts. After adjusting for propensity score, antipsychotics were not associated with an increased risk of post-stroke infection (odds ratio 0.99, 95% confidence interval 0.87-1.14). CONCLUSION: While our study did not find conclusive evidence linking antipsychotic medication to an increased risk of post-stroke infection, prescribing these medications should still be approached with prudence. Until further research can provide more definitive insights, clinicians should carefully weigh the potential infection risks when considering antipsychotic treatment during the acute stroke care period.

Identification of IGF-1 Effects on White Adipose Tissue and Hippocampus in Alzheimer's Disease Mice via Transcriptomic and Cellular Analysis.

Alzheimer's disease (AD) stands as the most prevalent neurodegenerative disorder, characterized by a multitude of pathological manifestations, prominently marked by the aggregation of amyloid beta. Recent investigations have revealed a compelling association between excessive adiposity and glial activation, further correlating with cognitive impairments. Additionally, alterations in levels of insulin-like growth factor 1 (IGF-1) have been reported in individuals with metabolic conditions accompanied by memory dysfunction. Hence, our research endeavors to comprehensively explore the impact of IGF-1 on the hippocampus and adipose tissue in the context of Alzheimer's disease. To address this, we have conducted an in-depth analysis utilizing APP/PS2 transgenic mice, recognized as a well-established mouse model for Alzheimer's disease. Upon administering IGF-1 injections to the APP/PS2 mice, we observed notable alterations in their behavioral patterns, prompting us to undertake a comprehensive transcriptomic analysis of both the hippocampal and adipose tissues. Our data unveiled significant modifications in the functional profiles of these tissues. Specifically, in the hippocampus, we identified changes associated with synaptic activity and neuroinflammation. Concurrently, the adipose tissue displayed shifts in processes related to fat browning and cell death signaling. In addition to these findings, our analysis enabled the identification of a collection of long non-coding RNAs and circular RNAs that exhibited significant changes in expression subsequent to the administration of IGF-1 injections. Furthermore, we endeavored to predict the potential roles of these identified RNA molecules within the context of our study. In summary, our study offers valuable transcriptome data for hippocampal and adipose tissues within an Alzheimer's disease model and posits a significant role for IGF-1 within both the hippocampus and adipose tissue.

Accuracy of Measurements of the Structural Reserve for Upper Limb Function in Patients With Moderate-to-Severe Stroke.

BACKGROUND: The structural integrity of the corticospinal tract (CST) is an important biomarker of poststroke upper limb recovery. Injured CST undergoes Wallerian degeneration rostrocaudally during the first few months. However, there is no standardized measurement of the structural integrity of the CST. This study aimed to determine the measurement accuracy of the structural integrity of the CST. METHODS: This cross-sectional study included 50 consecutive patients with middle cerebral artery stroke who underwent diffusion tensor imaging upon transfer from the acute stroke unit to the inpatient rehabilitation facility (2018-2022). We evaluated hemiplegic upper limb function using Shoulder Abduction and Finger Extension (SAFE) scores. Fractional anisotropy values representing the structural integrity of the CST were evaluated using 4 region of interest-based and 2 tract-based measurements, including the posterior limb of internal capsule, cerebral peduncle, pons, pontomedullary junction, entire CST, and CST in the brainstem. Multivariate linear regression models and the area under the curve (AUC) were used to determine measurement accuracy for hemiplegic upper limb function. RESULTS: The structural integrity of the CST at the pontomedullary junction showed the highest explanatory power, followed by the entire CST, in the multivariate linear regression models (adjusted R2=0.459 and 0.425, respectively). The structural integrity of the CST at the pontomedullary junction also showed the highest AUC, followed by the entire CST, in discriminating patients with a SAFE score of <8 or 5 from those with SAFE ≥8 or 5 (SAFE <8: AUC, 0.90 [95% CI, 0.80-1.00]; AUC, 0.83 [0.66-0.99]; SAFE <5: AUC, 0.87 [0.77-0.96]; AUC, 0.83, [0.72-0.95], respectively). CONCLUSIONS: The structural integrity of the CST measured at the pontomedullary junction or entire CST demonstrated the highest accuracy for hemiplegic upper limb function in the subacute phase of stroke.

Evidence of lateralised white matter plasticity: A longitudinal study of balance performance in nonexpert healthy adults.

Training-induced plasticity by practicing expert skills has been of particular interest; however, little is known about white matter plasticity for improving a fundamental element of body function, such as balance or postural control. This study explored white matter plasticity in nonexpert healthy adults, based on stepwise balance training. Seventeen participants were included and performed a home-based balance training program for 4 weeks (30 min/day, 3 days/week). Before commencing training, they underwent a baseline diffusion tensor imaging scan. A second scan was acquired at the end of the 4-week training. Lateralised balance load was applied on the right leg to contrast any lateralised effect on the white matter tracts. The balance function was assessed using the Community Balance & Mobility Scale. We examined changes in the fractional anisotropy values of the tracts of interest between pre- and post-training. After the 4-week training, the fractional anisotropy values were enhanced in the right superior cerebellar peduncle, transverse pontine fibre, body of the corpus callosum, left fornix and left uncinate fasciculus. The Community Balance & Mobility Scale score improved after 4-week training, but an association with changes in fractional anisotropy values cannot be evaluated due to the ceiling effect of the balance assessment tools. Balance training can strengthen the cerebro-cerebellar and interhemispheric structural connections and induce microstructural changes in the limbic structures, including the fornix and uncinate fasciculus. The effect of a lateralised balance load could be projected to the specific white matter tracts in a lateralised manner.

Circular RNA Tmcc1 improves astrocytic glutamate metabolism and spatial memory via NF-κB and CREB signaling in a bile duct ligation mouse model: transcriptional and cellular analyses.

BACKGROUND: Hepatic encephalopathy-induced hyperammonemia alters astrocytic glutamate metabolism in the brain, which is involved in cognitive decline. To identify specific therapeutic strategies for the treatment of hepatic encephalopathy, various molecular signaling studies, such as non-coding RNA functional study, have been conducted. However, despite several reports of circular RNAs (circRNAs) in the brain, few studies of circRNAs in hepatic encephalopathy-induced neuropathophysiological diseases have been conducted. METHODS: In this study, we performed RNA sequencing to identify whether the candidate circRNA cirTmcc1 is specifically expressed in the brain cortex in a bile duct ligation (BDL) mouse model of hepatic encephalopathy. RESULTS: Based on transcriptional and cellular analysis, we investigated the circTmcc1-dysregulation-induced changes in the expression of several genes that are associated with intracellular metabolism and astrocyte function. We found that the circTmcc1 binds with the NF-κB p65-CREB transcriptional complex and regulates the expression of the astrocyte transporter EAAT2. Furthermore, circTmcc1 contributed to the secretion of proinflammatory mediators and glutamate metabolism in astrocytes and subsequently modulated an improvement in spatial memory by mediating neuronal synaptic plasticity. CONCLUSIONS: Thus, circTmcc1 may be a promising circRNA candidate for targeted interventions to prevent and treat the neuropathophysiological complications that occur due to hepatic encephalopathy.

Human cytomegalovirus microRNA miR-US4-1 inhibits CD8(+) T cell responses by targeting the aminopeptidase ERAP1.

Major histocompatibility complex (MHC) class I molecules present peptides on the cell surface to CD8(+) T cells, which is critical for the killing of virus-infected or transformed cells. Precursors of MHC class I-presented peptides are trimmed to mature epitopes by the aminopeptidase ERAP1. The US2-US11 genomic region of human cytomegalovirus (HCMV) is dispensable for viral replication and encodes three microRNAs (miRNAs). We show here that HCMV miR-US4-1 specifically downregulated ERAP1 expression during viral infection. Accordingly, the trimming of HCMV-derived peptides was inhibited, which led to less susceptibility of infected cells to HCMV-specific cytotoxic T lymphocytes (CTLs). Our findings identify a previously unknown viral miRNA-based CTL-evasion mechanism that targets a key step in the MHC class I antigen-processing pathway.

Profiling and Cellular Analyses of Obesity-Related circRNAs in Neurons and Glia under Obesity-like In Vitro Conditions.

Recent evidence indicates that the pathogenesis of neurodegenerative diseases, including Alzheimer's disease, is associated with metabolic disorders such as diabetes and obesity. Various circular RNAs (circRNAs) have been found in brain tissues and recent studies have suggested that circRNAs are related to neuropathological mechanisms in the brain. However, there is a lack of interest in the involvement of circRNAs in metabolic imbalance-related neuropathological problems until now. Herein we profiled and analyzed diverse circRNAs in mouse brain cell lines (Neuro-2A neurons, BV-2 microglia, and C8-D1a astrocytes) exposed to obesity-related in vitro conditions (high glucose, high insulin, and high levels of tumor necrosis factor-alpha, interleukin 6, palmitic acid, linoleic acid, and cholesterol). We observed that various circRNAs were differentially expressed according to cell types with many of these circRNAs conserved in humans. After suppressing the expression of these circRNAs using siRNAs, we observed that these circRNAs regulate genes related to inflammatory responses, formation of synaptic vesicles, synaptic density, and fatty acid oxidation in neurons; scavenger receptors in microglia; and fatty acid signaling, inflammatory signaling cyto that may play important roles in metabolic disorders associated with neurodegenerative diseases.

Human lncRNA SUGCT-AS1 Regulates the Proinflammatory Response of Macrophage.

Macrophages are the major primary immune cells that mediate the inflammatory response. In this process, long non-coding RNAs (lncRNAs) play an important, yet largely unknown role. Therefore, utilizing several publicly available RNA sequencing datasets, we predicted and selected lncRNAs that are differentially expressed in M1 or M2 macrophages and involved in the inflammatory response. We identified SUGCT-AS1, which is a human macrophage-specific lncRNA whose expression is increased upon M1 macrophage stimulation. Conditioned media of SUGCT-AS1-depleted M1 macrophages induced an inflammatory phenotype of vascular smooth muscle cells, which included increased expression of inflammatory genes (IL1B and IL6), decreased contractile marker proteins (ACTA2 and SM22α), and increased cell migration. Depletion of SUGCT-AS1 promoted the expression and secretion of proinflammatory cytokines, such as TNF, IL1B, and IL6, in M1 macrophages, and transcriptomic analysis showed that SUGCT-AS1 has functions related to inflammatory responses and cytokines. Furthermore, we found that SUGCT-AS1 directly binds to hnRNPU and regulates its nuclear-cytoplasmic translocation. This translocation of hnRNPU altered the proportion of the MALT1 isoforms by regulating the alternative splicing of MALT1, a mediator of NF-κB signaling. Overall, our findings suggest that lncRNAs can be used for future studies on macrophage regulation. Moreover, they establish the SUGCT-AS1/hnRNPU/MALT1 axis, which is a novel inflammatory regulatory mechanism in macrophages.

Roles of non-coding RNAs in intercellular crosstalk in cardiovascular diseases.

Complex diseases including cardiovascular disease are caused by a combination of the alternation of many genes and the influence of environments. Recently, non-coding RNAs (ncRNAs) have been shown to be involved in diverse diseases, and the functions of various ncRNAs have been reported. Many researchers have elucidated the mechanisms of action of these ncRNAs at the cellular level prior to in vivo and clinical studies of the diseases. Due to the characteristics of complex diseases involving intercellular crosstalk, it is important to study communication between multiple cells. However, there is a lack of literature summarizing and discussing studies of ncRNAs involved in intercellular crosstalk in cardiovascular diseases. Therefore, this review summarizes recent discoveries in the functional mechanisms of intercellular crosstalk involving ncRNAs, including microRNAs, long non-coding RNAs, and circular RNAs. In addition, the pathophysiological role of ncRNAs in this communication is extensively discussed in various cardiovascular diseases.

Single Nucleotide Polymorphisms May Increase the Risk of Aspiration Pneumonia in Post-Stroke Patients with Dysphagia.

This study aimed to evaluate whether genetic polymorphism is associated with an increased risk of infection, specifically post-stroke aspiration pneumonia. Blood samples were obtained from a total of 206 post-stroke participants (males, n = 136; mean age, 63.8 years). Genotyping was performed for catechol-O-methyltransferase (rs4680, rs165599), dopamine receptors (DRD1; rs4532, DRD2; rs1800497, DRD3; rs6280), brain-derived neurotrophic factor (rs6265), apolipoprotein E (rs429358, rs7412), and the interleukin-1 receptor antagonist gene (rs4251961). The subjects were stratified into two groups, aged < 65 (young) and ≥ 65 (elderly). Functional parameters and swallowing outcomes were measured at enrollment and at 3 months post-onset. The primary outcome was the incidence of aspiration pneumonia. Analysis of the association between genetic polymorphisms and aspiration pneumonia history showed that a minor C rs429358 allele was associated with the occurrence of aspiration pneumonia in the young group, both in the additive and the dominant models (odds ratio: 4.53; 95% CI: 1.60−12.84, p = 0.004). In the multivariable analysis, the minor C rs429358 allele increased the risk of post-stroke aspiration pneumonia in young stroke patients by 5.35 (95% CI: 1.64−20.88). In contrast, no such association was observed in the elderly group. Apolipoprotein E polymorphism may affect the risk of post-stroke aspiration pneumonia.

Obesity-linked circular RNA circTshz2-2 regulates the neuronal cell cycle and spatial memory in the brain.

Metabolic syndromes, including obesity, cause neuropathophysiological changes in the brain, resulting in cognitive deficits. Only a few studies explored the contribution of non-coding genes in these pathophysiologies. Recently, we identified obesity-linked circular RNAs (circRNA) by analyzing the brain cortices of high-fat-fed obese mice. In this study, we scrutinized a conserved and neuron-specific circRNA, circTshz2-2, which affects neuronal cell cycle and spatial memory in the brain. Transcriptomic and cellular analysis indicated that circTshz2-2 dysregulation altered the expression of cell division-related genes and induced cell cycle arrest at the G2/M phase of the neuron. We found that circTshz2-2 bound to the YY1 transcriptional complex and suppressed Bdnf transcription. Suppression of circTshz2-2 increased BDNF expression and reduced G2/M checkpoint proteins such as Cyclin B2 and CDK1 through BDNF/TrkB signaling pathway, resulting in cell cycle arrest and neurite elongation. Inversely, overexpression of circTshz2-2 decreased BDNF expression, induced cell cycle proteins, and shortened the neurite length, indicating that circTshz2-2 regulates neuronal cell cycle and structure. Finally, we showed that circTshz2-2 affects spatial memory in wild-type and obese mice. Our data have revealed potential regulatory roles of obesity-related circTshz2-2 on the neuronal cell cycle and memory function providing a novel link between metabolic syndromes and cognitive deficits.

Transcriptome Profile in the Mouse Brain of Hepatic Encephalopathy and Alzheimer's Disease.

Hepatic encephalopathy (HE) is a chronic metabolic disease accompanied by neuropathological and neuropsychiatric features, including memory deficits, psychomotor dysfunction, depression, and anxiety. Alzheimer's disease (AD), the most common neurodegenerative disease, is characterized by tau hyperphosphorylation, excessive amyloid beta (Aß) accumulation, the formation of fibrillary tangles, hippocampus atrophy, and neuroinflammation. Recent studies have suggested a positive correlation between HE and AD. Some studies reported that an impaired cholesterol pathway, abnormal bile acid secretion, excessive ammonia level, impaired Aß clearance, astrocytic dysfunction, and abnormal γ-aminobutyric acid GABAergic neuronal signaling in HE may also be involved in AD pathology. However, the mechanisms and related genes involved in AD-like pathology in the HE brain are unclear. Thus, we compared the cortical transcriptome profile between an HE mouse model, bile duct ligation (BDL), and an AD mouse model, the 5×FAD. Our study showed that the expression of many genes implicated in HE is associated with neuronal dysfunction in AD mice. We found changes in various protein-coding RNAs, implicated in synapses, neurogenesis, neuron projection, neuron differentiation, and neurite outgrowth, and non-coding RNAs possibly associated with neuropathology. Our data provide an important resource for further studies to elucidate AD-like pathophysiology in HE patients.

Transcriptome Profile of Thyroid Glands in Bile Duct Ligation Mouse Model.

Thyroid hormone (TH) contributes to multiple cellular mechanisms in the liver, muscle cells, adipose tissue, and brain, etc. In particular, the liver is an important organ in TH metabolism for the conversion of thyronine (T4) into triiodothyronine (T3) by the deiodinase enzyme. TH levels were significantly decreased and thyroid-stimulating hormone (TSH) levels were significantly increased in patients with liver failure compared with normal subjects. Among liver failure diseases, hepatic encephalopathy (HE) deserves more attention because liver damage and neuropathologies occur simultaneously. Although there is numerous evidence of TH dysregulation in the HE model, specific mechanisms and genetic features of the thyroid glands in the HE model are not fully understood. Here, we investigated the significantly different genes in the thyroid glands of a bile duct ligation (BDL) mouse model as the HE model, compared to the thyroid glands of the control mouse using RNA sequencing. We also confirmed the alteration in mRNA levels of thyroid gland function-related genes in the BDL mouse model. Furthermore, we evaluated the increased level of free T4 and TSH in the BDL mouse blood. Thus, we emphasize the potential roles of TH in liver metabolism and suggest that thyroid dysfunction-related genes in the HE model should be highlighted for finding the appropriate solution for an impaired thyroid system in HE.

Novel Small Molecule Inhibitors Targeting the IL-6/STAT3 Pathway or IL-1ß.

Development of small molecules that inhibit inflammatory cytokines is a desirable strategy for the treatment of inflammatory diseases such as rheumatoid arthritis (RA). Following up a previous study, we synthesized 10 novel compounds with a 2,5-diaminobenzoxazole moiety and evaluated their biological activities. Among them, compound 3e showed potent inhibitory activity on Interleukin 6 (IL-6)/Signal Transducer and Activator of Transcription 3 (STAT3) signaling inhibition (71.5%), and 3a showed excellent inhibitory activity on Interleukin 1 (IL-1ß) (92.1%). To test in vivo anti-inflammatory activity, compounds 3a and 3e were administered by intraperitoneal (IP) injection after subcutaneous (SC) injection of zymosan A into the right footpad of mice. Inflammation on the footpad was reduced after administration of compounds 3a and 3e. Especially, compound 3a showed a significant ameliorative effect on zymosan-induced inflammation. From the in vivo and in vitro test results, we confirmed that our synthesized compounds are effective on the RA animal model through inhibition of the IL-6/STAT3 signaling pathway. Since drugs developed with small molecule inhibitors have several advantages over biological drugs, further study on these compounds is needed for the development of potent SMI drugs on RA.

Integrity of the Inferior Cerebellar Peduncle Correlates with Ambulatory Function after Hemorrhagic Stroke.

OBJECTIVES: Cerebro-cerebellar connectivity plays a critical role in motor recovery after stroke; however, the underlying mechanism of walking recovery is unclear. The dorsal spinocerebellar pathway has been suggested as a biomarker of poststroke ambulatory function. We aimed to explore the association between ambulatory function and the dorsal spinocerebellar pathway's integrity after intracerebral hemorrhage (ICH). MATERIALS AND METHODS: Twenty-seven patients with ICH who were admitted for inpatient rehabilitation during the subacute phase of stroke and 27 age-matched healthy controls were included retrospectively. Ambulatory function was assessed using the Berg Balance Scale and Mobility score. We measured the fractional anisotropy (FA) values of the corticospinal tract (CST) and inferior cerebellar peduncle (ICP) as the final route of the dorsal spinocerebellar pathway. The FA laterality indices, representing the degree of degeneration, were calculated. A Spearman correlation analysis and multivariate linear regression models were used to determine the associations between the FA laterality indices and ambulatory function. RESULTS: An FA reduction was found in both the ipsilesional CST and contralesional ICP of the patients. The ICP FA laterality index exhibited a moderate correlation with ambulatory function (Berg Balance Scale, ρBBS=0.589; Mobility score, ρMS=0.619). On dividing the patient group into the moderate (mRS 3, 4) and severe disability (mRS 5) groups, a stronger correlation was found (ρBBS=0.777, ρMS=0.856, moderate disability; ρBBS=0.732, ρMS=0.797, severe disability). The ICP FA laterality index and age were independently associated with the Mobility score (R2=0.525). CONCLUSIONS: ICP degeneration occurs after ICH, and its degree is associated with ambulatory function after ICH.

P300/CBP-Associated Factor Activates Cardiac Fibroblasts by SMAD2 Acetylation.

Various heart diseases cause cardiac remodeling, which in turn leads to ineffective contraction. Although it is an adaptive response to injury, cardiac fibrosis contributes to this remodeling, for which the reactivation of quiescent myofibroblasts is a key feature. In the present study, we investigated the role of the p300/CBP-associated factor (PCAF), a histone acetyltransferase, in the activation of cardiac fibroblasts. An intraperitoneal (i.p.) injection of a high dose (160 mg/kg) of isoproterenol (ISP) induced cardiac fibrosis and reduced the amount of the PCAF in cardiac fibroblasts in the mouse heart. However, the PCAF activity was significantly increased in cardiac fibroblasts, but not in cardiomyocytes, obtained from ISP-administered mice. An in vitro study using human cardiac fibroblast cells recapitulated the in vivo results; an treatment with transforming growth factor-ß1 (TGF-ß1) reduced the PCAF, whereas it activated the PCAF in the fibroblasts. PCAF siRNA attenuated the TGF-ß1-induced increase in and translocation of fibrosis marker proteins. PCAF siRNA blocked TGF-ß1-mediated gel contraction and cell migration. The PCAF directly interacted with and acetylated mothers against decapentaplegic homolog 2 (SMAD2). PCAF siRNA prevented TGF-ß1-induced phosphorylation and the nuclear localization of SMAD2. These results suggest that the increase in PCAF activity during cardiac fibrosis may participate in SMAD2 acetylation and thereby in its activation.

The microRNA miR-134-5p induces calcium deposition by inhibiting histone deacetylase 5 in vascular smooth muscle cells.

Calcium deposition in vascular smooth muscle cells (VSMCs) is a form of ectopic ossification in blood vessels. It can result in rigidity of the vasculature and an increase in cardiac events. Here, we report that the microRNA miR-134-5p potentiates inorganic phosphate (Pi)-induced calcium deposition in VSMCs by inhibiting histone deacetylase 5 (HDAC5). Using miRNA microarray analysis of Pi-treated rat VSMCs, we first selected miR-134-5p for further evaluation. Quantitative RT-PCR confirmed that miR-134-5p was increased in Pi-treated A10 cells, a rat VSMC line. Transfection of miR-134-5p mimic potentiated the Pi-induced increase in calcium contents. miR-134-5p increased the amounts of bone runt-related transcription factor 2 (RUNX2) protein and bone morphogenic protein 2 (BMP2) mRNA in the presence of Pi but decreased the expression of osteoprotegerin (OPG). Bioinformatic analysis showed that the HDAC5 3'untranslated region (3'UTR) was one of the targets of miR-134-5p. The luciferase construct containing the 3'UTR of HDAC5 was down-regulated by miR-134-5p mimic in a dose-dependent manner in VSMCs. Overexpression of HDAC5 mitigated the calcium deposition induced by miR-134-5p. Our results suggest that a Pi-induced increase of miR-134-5p may cause vascular calcification through repression of HDAC5.