Association of three single nucleotide polymorphisms in the LPIN1 gene with milk production traits in cows of the Yaroslavl breed.

Lipin-1 is a member of the evolutionarily conserved family of proteins and is expressed predominantly in adipose tissue and skeletal muscle. On the one hand, lipin-1 is an enzyme that catalyzes the dephosphorylation of phosphatidic acid to diacylglycerol (DAG) and thus participates in the metabolic pathways of biosynthesis of storage lipids in the cell, membrane phospholipids, and intracellular signaling molecules. On the other hand, lipin-1 is able to be transported from the cytoplasm to the nucleus and is a coactivator of lipid metabolism gene transcription. It was shown, using the analysis of single nucleotide polymorphism (SNP) associations, that the lipin-1 coding gene (LPIN1) is a promising candidate gene for milk production traits in Holstein and Brown Swiss cows. However, it is unclear how much of its effect depends on the breed. The Yaroslavl dairy cattle breed was created in the 18-19 centuries in Russia by breeding northern Great Russian cattle, which were short and poor productive, but well adapted to local climatic conditions and bad food base. It was shown by whole genome genotyping and sequencing that the Yaroslavl breed has unique genetics compared to Russian and other cattle breeds. The aim of the study was to assess the frequency of alleles and genotypes of three SNPs in the LPIN1 gene and to study the association of these SNPs with milk production traits in Yaroslavl cows. Blood samples from 142 cows of the Yaroslavl breed were obtained from two farms in the Yaroslavl region. Genotyping of SNPs was carried out by polymerase chain reaction-restriction fragment length polymorphism method. Associations of SNPs with 305-day milk yield, fat yield, fat percentages, protein yield, and protein percentages were studied from the first to the fourth lactation. Statistical tests were carried out using a mixed linear model, taking into account the relationship between individuals. We identified three SNPs - rs110871255, rs207681322 and rs109039955 with a frequency of a rare allele of 0.042-0.261 in Yaroslavl cows. SNP rs110871255 was associated with fat yield during the third and fourth lactations. SNP rs207681322 was associated with milk yield for the second, third and fourth lactations, as well as protein yield for the third lactation. Thus, we identified significant associations of SNPs rs207681322 and rs110871255 in the LPIN1 gene with a number of milk production traits during several lactations in Yaroslavl cows.

Proteasome-Associated Proteins, PA200 and ECPAS, Are Essential for Murine Spermatogenesis.

Proteasomes are highly sophisticated protease complexes that degrade non-lysosomal proteins, and their proper regulation ensures various biological functions such as spermatogenesis. The proteasome-associated proteins, PA200 and ECPAS, are predicted to function during spermatogenesis; however, male mice lacking each of these genes sustain fertility, raising the possibility that these proteins complement each other. To address this issue, we explored these possible roles during spermatogenesis by producing mice lacking these genes (double-knockout mice; dKO mice). Expression patterns and quantities were similar throughout spermatogenesis in the testes. In epididymal sperm, PA200 and ECPAS were expressed but were differentially localized to the midpiece and acrosome, respectively. Proteasome activity was considerably reduced in both the testes and epididymides of dKO male mice, resulting in infertility. Mass spectrometric analysis revealed LPIN1 as a target protein for PA200 and ECPAS, which was confirmed via immunoblotting and immunostaining. Furthermore, ultrastructural and microscopic analyses demonstrated that the dKO sperm displayed disorganization of the mitochondrial sheath. Our results indicate that PA200 and ECPAS work cooperatively during spermatogenesis and are essential for male fertility.

Hydroxychloroquine sulfate: A novel treatment for lipin-1 deficiency?

BACKGROUND: Lipin-1 deficiency is a life-threatening disease that causes severe rhabdomyolysis (RM) and chronic symptoms associated with oxidative stress. In the absence of treatment, Hydroxychloroquine sulfate (HCQ) was administered to patients off label use on a compassionate basis in order to improve their physical conditions. METHODS: Eleven patients with LPIN1 mutations were treated with HCQ. Clinical and biological efficacy and tolerance were assessed, including pain and quality of life, physical capacities, cardiopulmonary parameters, creatine kinase levels and plasma proinflammatory cytokines. To explore a dose-dependent effect of HCQ, primary myoblasts from 4 patients were incubated with various HCQ concentrations in growth medium (GM) or during starvation (EBSS medium) to investigate autophagy and oxidative stress. FINDINGS: Under HCQ treatment, patient physical capacities improved. Abnormal cardiac function and peripheral muscle adaptation to exercise were normalized. However, two patients who had the highest mean blood HCQ concentrations experienced RM. We hypothesized that HCQ exerts deleterious effects at high concentrations by blocking autophagy, and beneficial effects on oxidative stress at low concentrations. We confirmed in primary myoblasts from 4 patients that high in vitro HCQ concentration (10 µM) but not low concentration (1 µM and 0.1 µM) induced autophagy blockage by modifying endolysosomal pH. Low HCQ concentration (1 µM) prevented reactive oxygen species (ROS) and oxidized DNA accumulation in myoblasts during starvation. INTERPRETATION: HCQ improves the condition of patients with lipin-1 deficiency, but at low concentrations. In vitro, 1 µM HCQ decreases oxidative stress in myoblasts whereas higher concentrations have a deleterious effect by blocking autophagy.

Use of dexamethasone in acute rhabdomyolysis in LPIN1 deficiency.

Introduction: LPIN1 deficiency is an autosomal recessive form of early childhood recurrent severe rhabdomyolysis. Although not completely lucid yet, LPIN1 has been shown to modulate endosomal-related pro-inflammatory responses via peroxisome proliferator-activated receptor α (PPARα) and PPARγ coactivator 1α (PGC-1α). Treatment with anti-inflammatory agents such as dexamethasone has been proposed to improve the outcome. Case: We report a male toddler with recurrent episodes of complicated rhabdomyolysis, requiring prolonged intensive care unit admissions. Whole exome sequencing revealed a common homozygous 1.7 kb intragenic deletion in LPIN1. Despite optimal metabolic cares, the patient presented with an extremely high CK level where he benefited from intravenous dexamethasone (0.6 mg/Kg/day) for a period of 6 days. Results: Dexamethasone administration shortened the course of active rhabdomyolysis, intensive care admission and rehabilitation. It also prevented rhabdomyolysis-related complications such as kidney injury and compartment syndrome. Conclusion: Our patient showed a favorable response to parenteral dexamethasone, in addition to hyperhydration with IV fluids, sufficient calorie intake, and restricted dietary fat. The improvement with corticosteroids suggests an uncontrolled inflammatory response as the pathophysiology of LPIN1 deficiency.

Case report: Rhabdomyolysis in children in acute and chronic disease-a challenging condition in pediatric emergency medicine.

Rhabdomyolysis is a challenging condition in pediatric emergency departments (PED): It ranges from asymptomatic illness with isolated elevation of creatine kinase (CK) levels to a life-threatening condition associated with extreme elevations in CK, electrolyte imbalances, circulatory failure (CF), acute kidney injury (AKI), and multi-organ disease. Most common causes of rhabdomyolysis are viral myositis and trauma, hereditary metabolic myopathies must be considered when facing rhabdomyolysis in early childhood. We report two cases of severe rhabdomyolysis with CF in our PED, thereby summarizing first-line management of rhabdomyolysis.

Two tales of LPIN1 deficiency: from fatal rhabdomyolysis to favorable outcome of acute compartment syndrome.

LPIN1 deficiency is an autosomal recessive disease caused by biallelic mutations in LPIN1, where impaired fatty acid metabolism leads to stress in skeletal muscle, resulting in severe rhabdomyolysis, often triggered by fever, exercise, fasting, and anesthesia. It is the second most common cause of severe, recurrent episodes of rhabdomyolysis in early childhood which can result in serious morbidity and mortality. To date, 71 patients have been published in 20 clinical studies in the form of case series. We describe two previously unreported cases, one with a novel LPIN1 mutation that resulted in mortality, and another, to the best of our knowledge, with the first reported compartment syndrome managed with a favorable outcome in this disorder. Recognition of the complications including ventricular arrythmias, acute renal failure and compartment syndrome on the severe end of the spectrum may change the outcome and prognosis of this devastating condition.

LPIN1 Induces Gefitinib Resistance in EGFR Inhibitor-Resistant Non-Small Cell Lung Cancer Cells.

Drug resistance limits the efficacy of targeted therapies, including tyrosine kinase inhibitors (TKIs); however, a substantial portion of the drug resistance mechanisms remains unexplained. In this study, we identified LPIN1 as a key factor that regulates gefitinib resistance in epidermal growth factor receptor (EGFR)-mutant non-small cell lung cancer (NSCLC) cells. Unlike TKI-sensitive HCC827 cells, gefitinib treatment induced LPIN1 expression and increased diacylglycerol concentration in TKI-resistant H1650 cells, followed by the activation of protein kinase C delta and nuclear factor kappa B (NF-κB) in an LPIN1-dependent manner, resulting in cancer cell survival. Additionally, LPIN1 increased the production of lipid droplets, which play an important role in TKI drug resistance. All results were recapitulated in a patient-derived EGFR-mutant NSCLC cell line. In in vivo tumorigenesis assay, we identified that both shRNA-mediated depletion and pharmaceutical inhibition of LPIN1 clearly reduced tumor growth and confirmed that gefitinib treatment induced LPIN1 expression and LPIN1-dependent NF-κB activation (an increase in p-IκBα level) in tumor tissues. These results suggest an effective strategy of co-treating TKIs and LPIN1 inhibitors to prevent TKI resistance in NSCLC patients.

LPIN1 rhabdomyolysis: A single site cohort description and treatment recommendations.

Individuals with LPIN1 deficiency have early recurrent, life-threatening rhabdomyolysis but the full phenotypic spectrum and optimal treatment of the disorder remains unknown. Here we report the clinical details and treatment outcomes of 6 patients from our health system. The average age of presentation in our cohort was 23.8 months ±11.6 months (range 15-46 months). The average number of days for each hospitalization for this cohort is 11.7±13.2 days. Creatinine kinase (CK) levels peak during our care averaged 607,725 units/L (range 157,000-1,100,000 units/L). We observed that aspartate aminotransferase levels paralleled the CK levels in its elevation and resolution (Pearson's correlation R = 0.995); while alanine aminotransferase paralleled the elevation but lagged in the resolution of CK levels (R = 0.728). Unlike historical accounts, in our patient population, rhabdomyolysis was sometimes seen without inciting viral or traumatic events. We also cared for multiple individuals that had received treatment at other centers. This allowed us to compare multiple practice approaches and led to a standardized Care Recommendations.

LPIN1 Is a Regulatory Factor Associated With Immune Response and Inflammation in Sepsis.

Objectives: Sepsis is a clinical disease that is typically treated in the intensive care unit, and the complex pathophysiology under this disease has not been thoroughly understood. While ferroptosis is involved in inflammation and infection, its effect in sepsis is still unknown. The study aimed to identify ferroptosis-related genes in sepsis, providing translational potential therapeutic targets. Methods: The dataset GSE65682 was used to download the sample source from the Gene Expression Omnibus (GEO) database. Consensus weighted gene co-expression network analysis (WGCNA) was performed to find suspected modules of sepsis. The differentially expressed genes (DEGs) most significantly associated with mortality were intersected with those altered by lipopolysaccharide (LPS) treatment and were further analyzed for the identification of main pathways of Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis. The related pathway markers were further verified by qPCR. Results: A total of 802 blood samples with sepsis were included for WGCNA, which identified 21 modules. Intersected with ferroptosis databases and LPS treatment groups, we identified two ferroptosis-related genes: PEBP1 and LPIN1. Only LPIN1 contributes to a poor outcome. Then, 205 DEGs were further identified according to the high or low LPIN1 expression. Among them, we constructed a gene regulatory network with several transcriptional factors using the NetworkAnalyst online tool and identified that these genes mostly correlate with inflammation and immune response. The immune infiltration analysis showed that lower expression of LPIN1 was related to macrophage infiltration and could be an independent predictor factor of the survival status in sepsis patients. Meanwhile, the multivariate Cox analysis showed that LPIN1 had a significant correlation with survival that was further verified by in vitro and in vivo experiments. Conclusion: In conclusion, LPIN1 could become a reliable biomarker for patient survival in sepsis, which is associated with immune and inflammation status.

Raphani Semen (Raphanus sativus L.) Ameliorates Alcoholic Fatty Liver Disease by Regulating De Novo Lipogenesis.

In this study, we investigated the pharmacological effect of a water extract of Raphani Semen (RSWE) on alcoholic fatty liver disease (AFLD) using ethanol-induced AFLD mice (the NIAAA model) and palmitic acid (PA)-induced steatosis HepG2 cells. An RSWE supplement improved serum and hepatic triglyceride (TG) levels of AFLD mice, as well as their liver histological structure. To explore the molecular action of RSWE in the improvement of AFLD, we investigated the effect of RSWE on four major pathways for lipid homeostasis in the liver: free fatty acid transport, lipogenesis, lipolysis, and ß-oxidation. Importantly, RSWE decreased the mRNA expression of de novo lipogenesis-related genes, such as Srebf1, Cebpa, Pparg, and Lpin1, as well as the protein levels of these factors, in the liver of AFLD mice. That these actions of RSWE affect lipogenesis was confirmed using PA-induced steatosis HepG2 cells. Overall, our findings suggest that RSWE has the potential for improvement of AFLD by inhibiting de novo lipogenesis.

Sequence Variation in the Bovine Lipin-1 Gene (LPIN1) and Its Association with Milk Fat and Protein Contents in New Zealand Holstein-Friesian × Jersey (HF × J)-cross Dairy Cows.

Lipin-1 is known to play a regulatory role in tissues that function in lipid metabolism. In dairy cows, the lipin-1 gene (LPIN1) is highly expressed in the mammary gland, but its function in milk production is less understood. In this study, we used PCR-single strand conformation polymorphism analysis to investigate sequence variation in three regions of bovine LPIN1 in New Zealand Holstein-Friesian × Jersey (HF × J)-cross dairy cows, including part of the 5' non-coding region, the region containing the LPIN1ß-spliced exon, and the sixth coding exon that encodes the putative transcriptional activating domain of the protein. No variation was found in the LPIN1ß-spliced exon, but two sequence variants containing one single nucleotide polymorphism (SNP) were identified in the 5' non-coding region and four sequence variants containing four non-synonymous SNPs were identified in the sixth coding exon. Among the three common variants of the sixth coding exon, variant C was found to be associated with an increase in milk fat percentage (presence 4.96 ± 0.034% vs. absence 4.81 ± 0.050%; p = 0.006) and milk protein percentage (presence 4.09 ± 0.017% vs. absence 3.99 ± 0.025%; p = 0.001), but no associations (p > 0.01) were detected for milk yield. These results suggest that variation in LPIN1 affect the synthesis of fat and proteins in milk and has potential as a gene-marker to improve milk production traits.

3D disorganization and rearrangement of genome provide insights into pathogenesis of NAFLD by integrated Hi-C, Nanopore, and RNA sequencing.

The three-dimensional (3D) conformation of chromatin is integral to the precise regulation of gene expression. The 3D genome and genomic variations in non-alcoholic fatty liver disease (NAFLD) are largely unknown, despite their key roles in cellular function and physiological processes. High-throughput chromosome conformation capture (Hi-C), Nanopore sequencing, and RNA-sequencing (RNA-seq) assays were performed on the liver of normal and NAFLD mice. A high-resolution 3D chromatin interaction map was generated to examine different 3D genome hierarchies including A/B compartments, topologically associated domains (TADs), and chromatin loops by Hi-C, and whole genome sequencing identifying structural variations (SVs) and copy number variations (CNVs) by Nanopore sequencing. We identified variations in thousands of regions across the genome with respect to 3D chromatin organization and genomic rearrangements, between normal and NAFLD mice, and revealed gene dysregulation frequently accompanied by these variations. Candidate target genes were identified in NAFLD, impacted by genetic rearrangements and spatial organization disruption. Our data provide a high-resolution 3D genome interaction resource for NAFLD investigations, revealed the relationship among genetic rearrangements, spatial organization disruption, and gene regulation, and identified candidate genes associated with these variations implicated in the pathogenesis of NAFLD. The newly findings offer insights into novel mechanisms of NAFLD pathogenesis and can provide a new conceptual framework for NAFLD therapy.

miRNA-124-3p targeting of LPIN1 attenuates inflammation and apoptosis in aged male rats cardiopulmonary bypass model of perioperative neurocognitive disorders.

Perioperative neurocognitive disorder (PND) is recently recommended to define the cognitive decrease during the perioperative period. However, the disease's underlying mechanisms remain unclear. MicroRNAs (miRNAs) are noncoding RNAs that play a vital role in regulating neuroregeneration and neuronal apoptosis. In this study, miR-124-3p was significantly reduced in the PND rat model after a cardiopulmonary bypass (CPB) procedure. MicroRNA-124 (miR-124)-3p-overexpressed lentivirus was constructed and injected via the intracerebroventricular method before CPB. Morris Water Maze test (WMW) and the Open-Field test (OFT) were used to measure behavior changes, data shows decline of cognitive function of rats after CPB. PND rats expressed higher Aß and p-Tau Protein by using immunohistochemistry (IHC) analyses and Enzyme-Linked Immune Sorbent Assay (ELISA). Moreover, the results of IHC, ELISA, Western Blot analysis (WB) and Terminal-deoxynucleotidyl Transferase Mediated Nick End Labeling Assay (TUNEL) showed CPB procedure induced inflammation and apoptosis in rats with PND. The data also revealed the protective function of miR-124-3p overexpression against PND in relieving inflammation, cell apoptosis, and alleviating repaired cognitive function. Moreover, miR-124-3p was predicted by directly targeting LPIN1. This study gives a novel viewpoint that miR-124-3p could improve the state of PND via modulating LPIN1, therefore providing a new strategy for preventing and treating PND in a preclinical application.

IL-33-Induced Transcriptional Activation of LPIN1 Accelerates Breast Tumorigenesis.

Phospholipids are crucial materials that are not only required for cell membrane construction but also play significant roles as signaling molecules. LPIN1 is an enzyme that displays phosphatidate phosphatase activity in the triglyceride and phospholipid synthesis pathway. Recent studies have shown that overexpression of LPIN1 is involved in breast tumorigenesis, but the underlying mechanism regulating LPIN1 expression has not been elucidated yet. In the present study, we showed that the IL-33-induced COT-JNK1/2 signaling pathway regulates LPIN1 mRNA and protein expression by recruiting c-Jun to the LPIN1 promoter in breast cancer cells. IL-33 dose-dependently and time-dependently increased LPIN1 mRNA and protein expression. Moreover, IL-33 promoted colony formation and mammary tumorigenesis via induction of LPIN1 expression, while inhibition of LPIN1 disturbed IL-33-induced cell proliferation and mammary tumorigenesis. IL-33-driven LPIN1 expression was mediated by the COT-JNK1/2 signaling pathway, and inhibition of COT or JNK1/2 reduced LPIN1 expression. COT-JNK1/2-mediated IL-33 signaling activated c-Jun and promoted its binding to the promoter region of LPIN1 to induce LPIN1 expression. These findings demonstrated the regulatory mechanism of LPIN1 transcription by the IL-33-induced COT/JNK1/2 pathway for the first time, providing a potential mechanism underlying the upregulation of LPIN1 in cancer.

SRC promotes lipogenesis: implications for obesity and breast cancer.

Remodeling of lipid metabolism has been implicated in cancers; however, it remains obscure how the lipid metabolic pathways are altered by oncogenic signaling to affect tumor development. We have recently shown that proto-oncogene tyrosine-protein kinase Src interacts with and phosphorylates the lipogenesis enzyme phosphatidate phosphatase LPIN1 to promote breast cancer development.

MiR-99b-5p Attenuates Adipogenesis by Targeting SCD1 and Lpin1 in 3T3-L1 Cells.

The number and distribution of adipocytes directly affect the quality of livestock meat products. The analysis of the adipogenesis mechanism is the basis for improving meat quality. The formation of adipocytes is regulated by many factors, including a class of endogenous small RNAs, named microRNA (miRNA). Previous studies have shown that miRNAs could affect adipogenesis by post-transcriptional regulation of target genes. In our study, a decreased miR-99b-5p expression level was found in the adipose tissue of obese mice. Overexpression of miR-99b-5p could increase cell proliferation by promoting the cell cycle while inhibiting cell differentiation. In addition, interference with miR-99b-5p obtained the opposite result. Furthermore, the proteomics sequencing analysis screened 1154 differentially expressed proteins, which are closely related to adipocyte differentiation and fatty acid metabolism. In addition, the results of the dual-luciferase test showed that miR-99b-5p can directly target the proteins SCD1 and Lpin1 with significantly different expression levels in proteomic sequencing. Then, this result was verified at the level of mRNA and protein in a further study. Collectively, these results suggested that miR-99b-5p may be a target for improving meat quality.

Lipin 1 deficiency causes adult-onset myasthenia with motor neuron dysfunction in humans and neuromuscular junction defects in zebrafish.

Lipin 1 is an intracellular protein acting as a phosphatidic acid phosphohydrolase enzyme controlling lipid metabolism. Human recessive mutations in LPIN1 cause recurrent, early-onset myoglobinuria, a condition normally associated with muscle pain and weakness. Whether and how lipin 1 deficiency in humans leads to peripheral neuropathy is yet unclear. Herein, two novel compound heterozygous mutations in LPIN1 with neurological disorders, but no myoglobinuria were identified in an adult-onset syndromic myasthenia family. The present study sought to explore the pathogenic mechanism of LPIN1 in muscular and neural development. Methods: The clinical diagnosis of the proband was compared to the known 48 cases of LPIN1 recessive homozygous mutations. Whole-exome sequencing was carried out on the syndromic myasthenia family to identify the causative gene. The pathogenesis of lipin 1 deficiency during somitogenesis and neurogenesis was investigated using the zebrafish model. Whole-mount in situ hybridization, immunohistochemistry, birefringence analysis, touch-evoke escape response and locomotion assays were performed to observe in vivo the changes in muscles and neurons. The conservatism of the molecular pathways regulated by lipin 1 was evaluated in human primary glioblastoma and mouse myoblast cells by siRNA knockdown, drug treatment, qRT-PCR and Western blotting analysis. Results: The patient exhibited adult-onset myasthenia accompanied by muscle fiber atrophy and nerve demyelination without myoglobinuria. Two novel heterozygous mutations, c.2047A>C (p.I683L) and c.2201G>A (p.R734Q) in LPIN1, were identified in the family and predicted to alter the tertiary structure of LPIN1 protein. Lipin 1 deficiency in zebrafish embryos generated by lpin1 morpholino knockdown or human LPIN1 mutant mRNA injections reproduced the myotomes defects, a reduction both in primary motor neurons and secondary motor neurons projections, morphological changes of post-synaptic clusters of acetylcholine receptors, and myelination defects, which led to reduced touch-evoked response and abnormalities of swimming behaviors. Loss of lipin 1 function in zebrafish and mammalian cells also exhibited altered expression levels of muscle and neuron markers, as well as abnormally enhanced Notch signaling, which was partially rescued by the specific Notch pathway inhibitor DAPT. Conclusions: These findings pointed out that the compound heterozygous mutations in human LPIN1 caused adult-onset syndromic myasthenia with peripheral neuropathy. Moreover, zebrafish could be used to model the neuromuscular phenotypes due to the lipin 1 deficiency, where a novel pathological role of over-activated Notch signaling was discovered and further confirmed in mammalian cell lines.

Acute recurrent rhabdomyolysis in a Chinese boy associated with a novel compound heterozygous LPIN1 variant: a case report.

BACKGROUND: LPIN1-related acute recurrent rhabdomyolysis (RM), first reported in 2008, is an autosomal recessive inherited metabolic disease. In recent years, LPIN1 gene variants have been identified as one of the main causes of severe RM in children in Western countries. The disease is extremely rare in China, and we report a case of acute recurrent RM caused by a novel compound heterozygous LPIN1 variant. CASE PRESENTATION: A 15-year-old Chinese boy presented with myalgia after strenuous exercise, accompanied by transient increases in serum creatine kinase and myoglobin and persistent hyperuricaemia and hyperbilirubinaemia. Genetic analysis using high-throughput genomic sequencing and Sanger sequencing revealed that there was a compound heterozygous variant in the LPIN1 gene of the proband: the paternal c.2047A > G(p.I683V) was an unreported missense variant, and the maternal c.2107_2108 insAGG(p.Q703delin sQE) was an unreported in-frame variant. CONCLUSIONS: In children with RM, LPIN1 variants should always be considered in the differential diagnosis. The clinical features of our case are atypical, which highlights the importance of an accurate diagnosis by genetic testing. If detected early, the condition may be controlled, and the prognosis may be improved.

LPIN1 downregulation enhances anticancer activity of the novel HDAC/PI3K dual inhibitor FK-A11.

Phosphatidylinositol-3 kinase (PI3K) inhibitor and histone deacetylase (HDAC) inhibitor have been developed as potential anticancer drugs. However, the cytotoxicity of PI3K inhibitor or HDAC inhibitor alone is relatively weak. We recently developed a novel HDAC/PI3K dual inhibitor FK-A11 and confirmed its enhanced cytotoxicity when compared to that of PI3K inhibitor or HDAC inhibitor alone on several cancer cell lines. However, the in vivo antitumor activity of FK-A11 was insufficient. We conducted high-throughput RNA interfering screening and identified gene LPIN1 which enhances the cytotoxicity of FK-A11. Downregulation of LPIN1 enhanced simultaneous inhibition of HDAC and PI3K by FK-A11 and enhanced the cytotoxicity of FK-A11. Propranolol, a beta-adrenoreceptor which is also a LPIN1 inhibitor, enhanced the in vitro and in vivo cytotoxicity and antitumor effect of FK-A11. These findings should help in the development of FK-A11 as a novel HDAC/PI3K dual inhibitor.

m6A Regulates Liver Metabolic Disorders and Hepatogenous Diabetes.

N6-methyladenosine (m6A) is one of the most abundant modifications on mRNAs and plays important roles in various biological processes. The formation of m6A is catalyzed by a methyltransferase complex (MTC) containing a key factor methyltransferase-like 3 (Mettl3). However, the functions of Mettl3 and m6A modification in hepatic lipid and glucose metabolism remain unclear. Here, we showed that both Mettl3 expression and m6A level increased in the livers of mice with high fat diet (HFD)-induced metabolic disorders. Overexpression of Mettl3 aggravated HFD-induced liver metabolic disorders and insulin resistance. In contrast, hepatocyte-specific knockout of Mettl3 significantly alleviated HFD-induced metabolic disorders by slowing weight gain, reducing lipid accumulation, and improving insulin sensitivity. Mechanistically, Mettl3 depletion-mediated m6A loss caused extended RNA half-lives of metabolism-related genes, which consequently protected mice against HFD-induced metabolic syndrome. Our findings reveal a critical role of Mettl3-mediated m6A in HFD-induced metabolic disorders and hepatogenous diabetes.