PR Domain Containing 16 Research Articles

Nicotinamide Riboside Ameliorates Fructose-Induced Lipid Metabolism Disorders in Mice by Activating Browning of WAT, and May Be Also Related to the Regulation of Gut Microbiota.

This study aims to observe the preventive effect of nicotinamide riboside (NR) on fructose-induced lipid metabolism disorders and explore its mechanism. Male C57BL/6J mice were fed a 20% fructose solution and given 400 mg/kg NR daily by gavage for 10 weeks. The results indicated that NR supplementation significantly reduced the body weight, liver weight, white adipose tissue (WAT) weight, serum, and hepatic lipid levels. NR upregulated the protein expression levels of sirtuin-1 (SIRT1), AMP-activated protein kinase (AMPK), PR domain containing 16 (PRDM16), uncoupling protein 1 (UCP1), peroxisome proliferator-activated receptor-gamma coactiva-tor-1-alpha (PGC-1α), nuclear respiratory factor 1-encoding gene (NRF1), mitochondrial transcription factor A (TFAM), cluster of differentiation 137 (CD137), transmembrane protein 26 (TMEM26), and T-box 1 (TBX1). Moreover, NR enhanced the Actinobacteria and Enterorhabdus abundance. Spearman's correlation analysis revealed that significant correlations exist between Firmicutes, Bacteroidetes, and Erysipelotrichaceae with browning-related indicators. In conclusion, NR could alleviate lipid metabolic abnormalities induced by fructose through activating SIRT1/AMPK-mediated browning of WAT. The mechanism by which NR improves fructose-induced lipid metabolism disorders may also be associated with the modulation of intestinal flora.

Overexpression of PRDM16 attenuates acute kidney injury progression: genetic and pharmacological approaches.

Acute kidney injury (AKI) presents as a condition marked by a sudden and rapid decrease in kidney function over a short timeframe, resulting from diverse causes. As a transcription factor, PR domain-containing 16 (PRDM16), has recently been implicated in brown fat biogenesis and heart diseases. Our recent works indicated that PRDM16 could suppress the occurrence of renal interstitial fibrosis in diabetic kidney disorder. Nonetheless, the effect and regulatory mechanism of PRDM16 in AKI remain elusive. Our study demonstrated that PRDM16 inhibited apoptosis induced by ischemic/reperfusion (I/R) in BUMPT (Boston University mouse kidney proximal tubular) cells and HK-2(Human Kidney-2)cells. Mechanistically, PRDM16 not only bound to the promoter region of S100 Calcium Binding Protein A6 (S100A6)and upregulated its expression but also interacted with its amino acids 945-949, 957-960, and 981-984 to suppress the p38MAPK and JNK axes via inhibition of PKC-η activity and mitochondrial reactive oxygen species (ROS) production. Furthermore, cisplatin- and I/R-stimulated AKI progression were ameliorated in PRDM16 proximal-tubule-specific knockin mice, whereas exacerbated in PRDM16 knockout proximal-tubule-specific mice). Moreover, we observed that formononetin ameliorated I/R- and cisplatin-triggered AKI progression in mice. Taken together, these findings reveal a novel self-protective mechanism in AKI, whereby PRDM16 regulates the S100A6/PKC-η/ROS/p38MAPK and JNK pathways to inhibit AKI progression.

Abstract 2077: The Epigenetic Regulator PRDM16 Controls Smooth Muscle Phenotypic Modulation And Atherosclerosis Risk

Despite decades of progress, coronary artery disease (CAD) remains the top cause of death worldwide. Additionally, trends in outcomes have worsened recently, highlighting the critical need for additional treatments. Human genetics has identified over 300 loci associated with CAD, but understanding the molecular mechanisms leading to disease remains a huge barrier to developing new therapies. These CAD-associated loci are enriched in smooth muscle cells (SMC) of the vascular wall, but no current therapies target these cells. Since insulin resistance is an important risk factor for CAD, understanding the molecular functions of genes associated with both insulin resistance and CAD will prioritize therapeutic candidates, especially if expressed in SMCs. One promising candidate is the gene PRDM16 (PR domain containing 16), which is highly expressed in vascular tissue. PRDM16 regulates cell fate decisions and insulin resistance in adipose tissue, but its role in atherosclerosis and SMC function is unknown. Recent advances in lineage tracing and conditional SMC knockout mouse models in conjunction with single cell technologies have demonstrated the cellular trajectories of SMC into several cellular states, including fibromyocytes (FMC) and chondromyocytes (CMC). Here, we employ this innovative approach to understand the role of Prdm16 on SMC phenotypic modulation in vivo and its role in the development of FMC and CMC. We also demonstrate the impact of Prdm16 in atherosclerosis and other important lesion characteristics relating to disease risk. We validate these effects in vitro and employ epigenetic analysis to identify the gene regulatory mechanisms whereby PRDM16 mediates its effects on SMC phenotypic modulation. Collectively these data demonstrate that PRDM16 is a causal factor that promotes risk of CAD.

Cell-autonomous Action of the FGF19 Promotes UCP1 Expression and Function in Human Brown Adipocytes

Fibroblast growth factor 19 (FGF19) is an intestine-derived hormone that regulates glucose and energy metabolism. Central and systemic administration of human FGF19 in mice promotes increased energy expenditure and body weight loss through mechanisms that are not fully understood. In this study, we investigated whether FGF19 can activate thermogenesis in brown adipocytes (BA) in a cell-autonomous manner. We differentiated immortalized human brown preadipocytes into mature adipocytes with adipogenic induction media in the presence and absence of FGF19 for 18 days to evaluate the effects of FGF19 on adipogenesis and thermogenesis. Through qPCR and RNA-sequencing analyses, we observed that FGF19 receptors were expressed in both brown preadipocytes and mature BA. However, the obligatory FGF19 co-receptor, β-klotho, was not expressed in preadipocytes, suggesting that the effects of FGF19 must occur preferentially in mature BA. Lipid staining with Oil Red O as well as gene expression of the adipogenic markers fatty acid binding protein (FABP4) and peroxisome proliferator activated receptor-γ (PPAR-γ) showed that adipogenesis was not affected by FGF19. We then treated mature BA with FGF19 (100 ng/mL) acutely and chronically to evaluate FGF19-induced changes in signaling, gene transcription, and thermogenic function. FGF19 signaling was assessed by measuring ERK1/2 phosphorylation levels, which increased within 5 min and remained elevated for at least 30 min after treatment. Using Seahorse assays, we observed that 24-hour FGF19 treatment promoted increased basal respiration, ATP production, and proton leak in human BA, indictive of enhanced mitochondrial function. Since proton leak across the inner membrane through the uncoupling protein 1 (UCP1) generates heat, we assessed the expression of UCP1 and other thermogenic genes. Interestingly, FGF19 treatment specifically increased UCP1 gene expression without affecting other classical adrenergic-mediated thermogenic genes, such as deiodinase 2 (DIO2), peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC1-α), PR domain containing 16 (PRDM16), and cell death-inducing DNA fragmentation factor A (CIDEA). These findings suggest that FGF19 regulates UCP1 expression through non-canonical pathways. Future work will elucidate the mechanism by which FGF19 promotes UCP1 gene expression in mature BA. Taken together, FGF19 stimulates ERK1/2 phosphorylation and UCP1 expression in human BA, leading to enhanced mitochondrial respiration. These results provide new mechanistic insights into FGF19’s effects on metabolic regulation. Topic subcategories: Adipocyte biology. Funding sources: Sao Paulo Research Foundation (FAPESP): 2022/15148-2 and NIH R01 DK102898. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Inhibition of protein kinase C increases Prdm14 level to promote self-renewal of embryonic stem cells through reducing Suv39h-induced H3K9 methylation

Inhibition of protein Kinase C (PKC) efficiently promoted the self-renewal of embryonic stem cells (ESCs). However, information about the function of PKC inhibition remains lacking. Here, RNA- sequencing showed that the addition of Go6983 significantly inhibited the expression of de novo methyltransferases (Dnmt3a and Dnmt3b) and their regulator Dnmt3l, resulting in global hypomethylation of DNA in mouse ESCs. Mechanistically, PR domain-containing 14 (Prdm14), a site-specific transcriptional activator, partially contributed to Go6983-mediated repression of Dnmt3 genes. Administration of Go6983 increased Prdm14 expression mainly through the inhibition of PKCδ. High constitutive expression of Prdm14 phenocopied the ability of Go6983 to maintain` mouse ESC stemness in the absence of self-renewal-promoting cytokines. In contrast, the knockdown of Prdm14 eliminated the response to PKC inhibition and substantially impaired the Go6983-induced resistance of mouse ESCs to differentiation. Furthermore, LC‒MS profiling and Western blotting revealed low levels of Suv39h1 and Suv39h2 in Go6983-treated mouse ESCs. Suv39h enzymes are histone methyltransferases that recognize di- and trimethylated histone H3K9 specifically and usually function as transcriptional repressors. Consistently, the inhibition of Suv39h1 by RNA interference or the addition of the selective inhibitor chaetocin increased Prdm14 expression. Moreover, ChIP assays showed that Go6983 treatment led to decreased enrichment of di- and trimethylation of H3K9 at the Prdm14 promoter but increased RNA polymerase Ⅱ binding affinity. Together, our results provide novel insights into the pivotal association between PKC inhibition-mediated self-renewal and epigenetic changes, which will help us better understand the regulatory network of stem cell pluripotency.

Ketogenic diet with aerobic exercise can induce fat browning: potential roles of β-hydroxybutyrate.

Despite evidence suggesting that metabolic intermediates like β-HB influence white adipose tissue (WAT) metabolism, the precise molecular mechanisms remain unclear. The aim of this study was to investigate the impact of beta-hydroxybutyrate (β-HB) on the fat browning program and to explore the underlying molecular mechanisms using both in vitro and in vivo models. We assessed the effects of β-HB on fat browning in adipocytes using 3T3-L1 cells and rat models. We evaluated the effects of β-HB on fat browning, thermogenesis, lipid accumulation, adipokine expression, and mitochondrial biogenesis by treating mature 3T3-L1 adipocytes with sodium β-HB for 24 h or by continuously exposing preadipocytes to β-HB during the 8-day differentiation process. Male Sprague Dawley rats were divided into control, exercise only (EX), ketogenic diet only (KD), and combined exercise and ketogenic diet (KE) groups for an 8-week intervention involving diet and/or exercise. After intervention, we evaluated WAT histology, plasma lipids and adipokines, and the expression of markers related to fat browning, thermogenesis and mitochondrial biogenesis in WAT of rats. In our adipocyte culture experiments, β-HB reduced intracellular lipid accumulation by enhancing lipolysis and stimulated the expression of thermogenic and fat browning genes like uncoupling protein 1 (UCP1), PR domain containing 16 (PRDM16), and adipokines such as fibroblast growth factor 21 (FGF21) and Fibronectin type III domain-containing protein 5 (FDNC5). Additionally, β-HB activated the AMPK-SIRT1-PGC-1α pathway, with UCP1 and PRDM16 upregulation mediated by β-HB intracellular action and SIRT1 activity. In animal experiments, KE group raised β-HB levels, decreasing body weight and blood lipids. KD with EX promoted WAT browning possibly via AMPK-SIRT1-PGC-1α, augmenting PRDM16, UCP1, FGF21, and FNDC5 expression. β-HB induction via KD and/or EX shows potential in promoting WAT browning by activating mitochondrial biogenesis, lipolysis, and thermogenesis, suggesting that dietary and physical intervention inducing β-HB may benefit metabolic health.

Discovery of PRDM16-Mediated TRPA1 Induction as the Mechanism for Low Tubulo-Interstitial Fibrosis in Diabetic Kidney Disease.

The pathogenesis of Diabetic kidney disease(DKD) involves pathological changes in both tubulo-interstitium and the glomerulus. Surprisingly, tubulo-interstitial fibrosis (TIF), does not develop significantly until the late stage of DKD. Here, it is demonstrated that PR domain-containing 16 (PRDM16) is a key to the low level of TIF in DKD. In the experiments, PRDM16 is upregulated in high glucose-treated renal tubular cells, DKD mouse kidneys, and renal biopsy of human DKD patients via activation of NF-κB signal pathway. High glucose-induced expression of fibrotic proteins in renal tubular cells is suppressed by PRDM16. Mechanistically, PRDM16 bound to the promotor region of Transient receptor potential ankyrin 1 (TRPA1) to transactivate its expression and then suppressed MAPK (P38, ERK1/2) activation and downstream expression of TGF-β1. Knockout of PRDM16 from kidney proximal tubules in mice blocked TRPA1 expression and enhanced MAPK activation, TGF-β1 production, TIF development, and DKD progression, whereas knock-in of PRDM16 has opposite effects. In addition, overexpression of PRDM16 or its induction by formononetin ameliorated renal dysfunction and fibrosis in db/db diabetic mice. Finally, the above finding are detected in renal biopsies of DKD patients. Together, these results unveil PRDM16/TRPA1 as the mechanism responsible for the low level of TIF in the early stage of DKD by suppressing and TGF-β1 expression.

Cancer Associated PRDM9: Implications for Linking Genomic Instability and Meiotic Recombination.

The PR domain-containing 9 or PRDM9 is a gene recognized for its fundamental role in meiosis, a process essential for forming reproductive cells. Recent findings have implicated alterations in the PRDM9, particularly its zinc finger motifs, in the onset and progression of cancer. This association is manifested through genomic instability and the misregulation of genes critical to cell growth, proliferation, and differentiation. In our comprehensive study, we harnessed advanced bioinformatic mining tools to delve deep into the intricate relationship between PRDM9F and cancer. We analyzed 136,752 breakpoints and found an undeniable association between specific PRDM9 motifs and the occurrence of double-strand breaks, a phenomenon evidenced in every cancer profile examined. Utilizing R statistical querying and the Regioner package, 55 unique sequence variations of PRDM9 were statistically correlated with cancer, from a pool of 1024 variations. A robust analysis using the Enrichr tool revealed prominent associations with various cancer types. Moreover, connections were noted with specific phenotypic conditions and molecular functions, underlining the pervasive influence of PRDM9 variations in the biological spectrum. The Reactome tool identified 25 significant pathways associated with cancer, offering insights into the mechanistic underpinnings linking PRDM9 to cancer progression. This detailed analysis not only confirms the pivotal role of PRDM9 in cancer development, but also unveils a complex network of biological processes influenced by its variations. The insights gained lay a solid foundation for future research aimed at deciphering the mechanistic pathways of PRDM9, offering prospects for targeted interventions and innovative therapeutic approaches in cancer management.

Chinese medicine Jiangzhuo mixture regulates glucose and lipid metabolism in obese rats throughTLR4/IκBα/NF-κB signaling pathway.

To explore the mechanism of Chinese medicine Jiangzhuo mixture regulating glucose and lipid metabolism in obese rats. Thirty healthy male SD rats were randomly divided into normal control group, the model control group, and the Jiangzhuo mixture treatment group, with 10 rats in each group. The rats in the normal control group were fed with normal diet, the obesity model was induced by feeding high-adipose diet in the model control group and Jiangzhuo mixture treatment group, the rats in the treatment group were given with Jiangzhuo mixture 50 g·kg－1 by gavage. After 8 weeks of intervention, the blood glucose (GLU), total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol (HDL-C) levels were detected in three groups. Quantitative reverse transcription PCR were used to detect the expression levels of PR domain containing 16 (PRDM16) and uncoupling protein 1 (UCP1) in white and brown adipose tissue of rats in each group; Western blot was used to detect the expression of PRDM16 and UCP1 in the white and brown adipose of rats, and Toll-like receptor 4 (TLR4), IκBα and nuclear factor kappa-B (NF-κB) in the white adipose; immunohistochemical method was used to detect the expression of UCP1 protein in white and brown adipose tissue. Compared with the normal control group, the white adipose weight (P<0.01), white adipose coefficient (P<0.05) and Lee's coefficient (P<0.01) were significantly increased in the model control group; the contents of GLU, TC, TG and LDL-C were all increased, and the content of TG was significantly increased (P<0.05) in the model control group. The mRNA and protein expression levels of PRDM16 and UCP1 in white adipose and brown adipose were significantly decreased (P<0.05) in the model control group. Compared with the model control group, the white adipose weight and white adipose coefficient and Lee's coefficient were significantly reduced in the Jiangzhuo mixture treatment group (P<0.01), the levels of GLU, TC, TG, and LDL-C in the the treatment group were all reduced, and the content of TG was reduced more obviously (P<0.01); expression levels of PRDM16 and UCP1mRNA and protein were increased in brown and white adipose. Compared with the normal control group, the expression levels of TLR4, IκBα and NF-κB proteins in white adipose tissue of the model control group were significantly increased (all P<0.01), while the expression levels of these proteins in the Jiangzhuo mixture treatment group were significantly lower than those in the model control group (all P<0.05). Jiangzhuo mixture can alleviate high-adipose diet-induced increase in body adipose, abnormal expression of biochemical indexes and promote the expression of key transcription factor UCP1 and PRDM16 in white and brown adipose by regulating TLR4/IκBα/NF-κB signaling pathway in obese SD rats.

3-tert-Butyl-4-hydroxyanisole Perturbs Differentiation of C3H10T1/2 Mesenchymal Stem Cells into Brown Adipocytes through Regulating Smad Signaling.

3-tert-Butyl-4-hydroxyanisole (3-BHA), one of the most commonly used antioxidants in foodstuffs, has been identified as an environmental endocrine disruptor (EED) with obesogenic activity. Given the increasing concern on EED-caused dysfunction in lipid metabolism, whether 3-BHA could influence the development of brown adipocytes is worthy of being explored. In this study, the effect of 3-BHA on the differentiation of C3H10T1/2 mesenchymal stem cells (MSCs) into brown adipocytes was investigated. Exposure to 3-BHA promoted lipogenesis of the differentiated cells, as evidenced by the increased intracellular lipid accumulation and elevated expressions of adipogenic biomarkers, including peroxisome proliferator-activated receptor γ (PPARγ), Perilipin, Adiponectin, and fatty acid binding protein 4 (FABP4). Surprisingly, the thermogenic capacity of the differentiated cells was compromised as a result of 3-BHA exposure, because neither intracellular mitochondrial contents nor expressions of thermogenic biomarkers, including uncoupling protein 1 (UCP1), peroxisome proliferator-activated receptor γ coactivator 1α (PGC1α), cell-death-inducing DNA fragmentation factor α subunit-like effector A (CIDEA), and PR domain containing 16 (PRDM16), were increased by this chemical. The underlying molecular mechanism exploration revealed that, in contrast to p38 MAPK, 3-BHA stimulation induced phosphorylation of Smad1/5/8 in an exposure time-dependent manner, suggesting that this chemical-triggered Smad signaling was responsible for the shift of C3H10T1/2 MSC differentiation from a brown to white-like phenotype. The finding herein, for the first time, revealed the perturbation of 3-BHA in the development of brown adipocytes, uncovering new knowledge about the obesogenic potential of this emerging chemical of concern.

Paeonia lactiflora root decreases lipid accumulation through the induction of lipolysis and thermogenesis via AMPK activation in 3T3‑L1 cells.

Obesity is associated with high risk of mortality globally because obesity is associated with development of diseases such as diabetes, dyslipidemia, fatty liver disease, hypertension, and cancer. The present study aimed to identify the mechanism of action related to the anti‑obesity activity of Paeonia lactiflora root (PLR) based on its effects on lipid droplet accumulation. The inhibitory activity on lipid accumulation was analyzed through Oil‑Red O staining, and the changes in levels of lipid accumulation‑related proteins were analyzed using Western blot analysis. And the contents of triacylglycerol and free glycerol were analyzed using an ELISA Kit. PLR significantly inhibited the accumulation of lipid droplets and triacylglycerol in differentiating 3T3‑L1 cells. PLR increased phosphorylated‑hormone sensitive lipase (HSL), HSL and adipose triglyceride lipase (ATGL) and decreases perilipin‑1 in differentiating and fully differentiated 3T3‑L1 cells. Furthermore, treatment of fully differentiated 3T3‑L1 cells with PLR resulted in increased free glycerol levels. PLR treatment increased levels of peroxisome proliferator‑activated receptor‑gamma coactivator‑1 alpha (PGC‑1α), PR domain containing16 (PRDM16) and uncoupling protein 1 (UCP‑1) in both differentiating and fully differentiated 3T3‑L1 cells. However, the PLR‑mediated increase in lipolytic, such as ATGL and HSL, and thermogenic factors, such as PGC‑1a and UCP‑1, were decreased by inhibition of AMP‑activated protein kinase (AMPK) with Compound C. Taken together, these results suggest that PLR exerted anti‑obesity effects by regulating lipolytic and thermogenic factors via AMPK activation. Therefore, the present study provided evidence that PLR is a potential natural agent for the development of drugs to control obesity.

Exercise improves homeostasis of the intestinal epithelium by activation of apelin receptor-AMP-activated protein kinase signalling.

Intestinal remodelling is dynamically regulated by energy metabolism. Exercise is beneficial for gut health, but the specific mechanisms remain poorly understood. Intestine-specific apelin receptor (APJ) knockdown (KD) and wild-type male mice were randomly divided into two subgroups, with/without exercise, to obtain four groups: WT, WT with exercise, APJ KD and APJ KD with exercise. Animals in the exercise groups were subjected to daily treadmill exercise for 3weeks. Duodenum was collected at 48h after the last bout of exercise. AMP-activated protein kinase (AMPK) α1 KD and wild-type mice were also utilized for investigating the mediatory role of AMPK on exercise-induced duodenal epithelial development. AMPK and peroxisome proliferator-activated receptor γ coactivator-1α were upregulated by exercise via APJ activation in the intestinal duodenum. Correspondingly, exercise induced permissive histone modifications in the PR domain containing 16 (PRDM16) promoter to activate its expression, which was dependent on APJ activation. In agreement, exercise elevated the expression of mitochondrial oxidative markers. The expression of intestinal epithelial markers was downregulated due to AMPK deficiency, and AMPK signalling facilitated epithelial renewal. These data demonstrate that exercise-induced activation of the APJ-AMPK axis facilitates the homeostasis of the intestinal duodenal epithelium. KEY POINTS: Apelin receptor (APJ) signalling is required for improved epithelial homeostasis of the small intestine in response to exercise. Exercise intervention activates PRDM16 through inducing histone modifications, enhanced mitochondrial biogenesis and fatty acid metabolism in duodenum. The morphological development of duodenal villus and crypt is enhanced by the muscle-derived exerkine apelin through the APJ-AMP-activated protein kinase axis.

PRDM16 Deficiency in Vascular Smooth Muscle Cells Aggravates Abdominal Aortic Aneurysm

Abdominal aortic aneurysm (AAA) is usually asymptomatic until severe complications with high risk of lethality occur, predominantly involving aortic rupture. Currently, no drug-based treatments are available, primarily due to limited understanding of AAA pathogenesis. PR domain-containing protein 16 (PRDM16) is a transcriptional regulator that governs gene expression by cooperating with other transcription factors. It is highly expressed in the aorta, but its functions in the aortic tissue and AAA pathology are largely unknown. In this study, we investigated the roles of PRDM16 in vascular smooth muscle cells (VSMCs). By RNA-seq analysis, we found that VSMCs-specific Prdm16 knockout mice ( Prdm16 SMKO) already showed extensive changes in the expression of genes associated with extracellular matrix (ECM) remodeling and inflammation in the abdominal aorta under normal housing conditions without any pathological stimuli. We found that human AAA lesions displayed decreased PRDM16 expression in the aortic medial layer. Periadventitial elastase application to the suprarenal region of the abdominal aorta aggravated AAA formation in Prdm16 SMKO mice. During AAA development, VSMCs undergo apoptosis because of both intrinsic and environmental changes including inflammation and ECM remodeling. Prdm16 deficiency promoted inflammation and apoptosis in VSMCs. A disintegrin and metalloproteinase 12 (ADAM12) is a gelatinase which can degrade various ECM. We found that ADAM12 is a target of transcriptional repression by PRDM16. Adam12 knockdown reversed VSMC apoptosis induced by Prdm16 deficiency. Our study demonstrated that PRDM16 deficiency in VSMCs promoted ADAM12 expression and aggravates AAA formation, which may provide potential targets for AAA treatment. This work was partially supported by National Institutes of Health grants HL151524 (L. Chang) This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Potential Pathogenic Impact of Cow's Milk Consumption and Bovine Milk-Derived Exosomal MicroRNAs in Diffuse Large B-Cell Lymphoma.

Epidemiological evidence supports an association between cow's milk consumption and the risk of diffuse large B-cell lymphoma (DLBCL), the most common non-Hodgkin lymphoma worldwide. This narrative review intends to elucidate the potential impact of milk-related agents, predominantly milk-derived exosomes (MDEs) and their microRNAs (miRs) in lymphomagenesis. Upregulation of PI3K-AKT-mTORC1 signaling is a common feature of DLBCL. Increased expression of B cell lymphoma 6 (BCL6) and suppression of B lymphocyte-induced maturation protein 1 (BLIMP1)/PR domain-containing protein 1 (PRDM1) are crucial pathological deviations in DLBCL. Translational evidence indicates that during the breastfeeding period, human MDE miRs support B cell proliferation via epigenetic upregulation of BCL6 (via miR-148a-3p-mediated suppression of DNA methyltransferase 1 (DNMT1) and miR-155-5p/miR-29b-5p-mediated suppression of activation-induced cytidine deaminase (AICDA) and suppression of BLIMP1 (via MDE let-7-5p/miR-125b-5p-targeting of PRDM1). After weaning with the physiological termination of MDE miR signaling, the infant's BCL6 expression and B cell proliferation declines, whereas BLIMP1-mediated B cell maturation for adequate own antibody production rises. Because human and bovine MDE miRs share identical nucleotide sequences, the consumption of pasteurized cow's milk in adults with the continued transfer of bioactive bovine MDE miRs may de-differentiate B cells back to the neonatal "proliferation-dominated" B cell phenotype maintaining an increased BLC6/BLIMP1 ratio. Persistent milk-induced epigenetic dysregulation of BCL6 and BLIMP1 expression may thus represent a novel driving mechanism in B cell lymphomagenesis. Bovine MDEs and their miR cargo have to be considered potential pathogens that should be removed from the human food chain.

Naringin promotes fat browning mediated by UCP1 activation via the AMPK signaling pathway in 3T3-L1 adipocytes.

Induction of the brown adipocyte-like phenotype in white adipocytes (fat browning) is considered a promising therapeutic strategy to treat obesity. Naringin, a citrus flavonoid, has antioxidant, anti-inflammatory, and anticancer activities. We examined the application of naringin as an anti-obesity compound based on an investigation of its induction of fat browning in 3T3-L1 adipocytes. Naringin did not induce lipid accumulation in differentiated 3T3-L1 adipocytes. Additionally, naringin reduced the expression levels of proliferator-activated receptor gamma (PPARγ) and CCAAT/enhancer-binding protein alpha (C/EBPα) involved in adipogenesis during lipid metabolism and increased the levels of PPARα and adiponectin involved in fatty acid oxidation. The expression levels of fat browning markers uncoupling protein 1 (UCP1; involved in thermogenesis) and PR domain containing 16 (PRDM16) increased. In addition, naringin treatment resulted in the activation of PPARγ coactivator 1-alpha (PGC-1α), a factor related to UCP1 transcription and mitochondrial biogenesis. Moreover, the expression of beige adipocyte-specific genes such as Cd137, Cited1, Tbx1, and Tmem26 was also induced. The small multi-lipid droplets characteristic of beige adipocytes indicated that naringin treatment increased the levels of all lipolysis markers (hormone-sensitive lipase [HSL], adipose triglyceride lipase [ATGL], perilipin [PLIN], and protein kinase A [PKA]). Adenosine monophosphate-activated protein kinase (AMPK) and UCP1 levels increased by treatment with naringin alone; this was possibly mediated by the stimulation of the AMPK signaling pathway. According to mechanistic studies, naringin activated the thermogenic protein UCP1 via the AMPK signaling pathway. In conclusion, naringin induces fat browning and is a promising therapeutic agent for metabolic disorders based on the regulation of lipid metabolism.

Deletion of Spinophilin Promotes White Adipocyte Browning.

Browning of white adipose tissue (WAT) is suggested as a promising therapeutic approach to induce energy expenditure and counteract obesity and its associated complications. Systemic depletion of spinophilin (SPL) increases metabolism and improves energy balance in mice. In this study, we explored the mechanistic insight of SPL action in WAT browning. Gene expression and mitochondria tracker staining showed that visceral white adipose tissue (vWAT) harvested from SPL KO mice had a higher expression of classic browning-related genes, including uncoupling protein 1 (UCP1), Cell death inducing DFFA like effector A (CIDEA) and PR domain containing 16 (PRDM16), as well as a higher mtDNA level compared to vWAT from wild type (WT) control mice. When adipogenesis was induced in pre-adipocytes harvested from KO and WT mice ex vivo using the PPAR-γ agonist rosiglitazone (Rosi), SPL KO cells showed increased browning marker gene expression and mitochondria function compared to cells from WT mice. Increased PPAR-γ protein expression and nucleus retention in vWAT from SPL KO mice after Rosi treatment were also observed. The effect of SPL on vWAT browning was further confirmed in vivo when WT and KO mice were treated with Rosi. As a result, SPL KO mice lost body weight, which was associated with increased expression of browning maker genes in vWAT. In summary, our data demonstrate the critical role of SPL in the regulation of WAT browning.

Thermo-TRP channels are involved in BAT thermoregulation in cold-acclimated Brandt's voles.

Transient receptor potential (TRP) channels, which can sense temperature, pressure and mechanical stimuli, were involved in many physiological and biochemical reactions. Whether thermosensitive TRP channels (Thermo-TRPs) are involved in thermoregulation in small mammals is still not clear. We measured the changes of thermo-TRPs at 4°C, 23°C and 30°C in Brandt's voles (Lasiopodomys brandtii) to test the hypothesis that Thermo-TRPs are involved in cold-induced thermogenesis of brown adipose tissue (BAT) in small mammals. Results showed that air temperatures had no effect on body mass and rectal temperature, but the food intake and basal metabolic rate (BMR) in the 4°C group were significantly higher than in the 30°C group. Compared with 30°C group, the protein contents of uncoupling protein 1(UCP1), TRP vanilloid 2 (TRPV2), TRP ankyrin 1 (TRPA1), TRP melastatin 2 (TRPM2), silent Information Regulator T1 (SIRT1), AMP-activated protein kinase (AMPK) and Calcium/calmodulin-dependent protein kinase II (CaMKII) in BAT increased significantly in 4°C group, but there was no significant difference in the protein content of Thermo-TRPs in the hypothalamus among groups. Further, the expression of PRDM16 (PR domain containing 16) in inguinal white adipose tissue (iWAT) at 4°C was significantly higher than that at 30°C, but no difference was observed in the expression of other browning-related genes or TRPV2. In conclusion, TRP channels may participate in BAT thermoregulation through the CaMKII, AMPK, SIRT1 and UCP1 pathway in cold-acclimated Brandt's voles.

Pro-Inflammatory of PRDM1/SIRT2/NLRP3 Axis in Monosodium Urate-Induced Acute Gouty Arthritis

PR domain-containing 1 with zinc finger domain (PRDM1) has been reported as a promoter of inflammation, which is a critical process involved in the pathogenesis of acute gouty arthritis. Herein, we sought to ascertain the function of PRDM1 in the development of acute gouty arthritis and related mechanisms. At first, peripheral blood-derived monocytes from patients with acute gouty arthritis and healthy individuals were collected as experimental samples. Then, macrophages were induced from monocytes using phorbol myristate acetate (PMA). The expression patterns of PRDM1, sirtuin 2 (SIRT2), and NLR family, pyrin domain-containing 3 (NLRP3) were characterized by RT-qPCR and Western blot assay. PMA-induced macrophages were stimulated by monosodium urate (MSU) for in vitro experimentation. Meanwhile, a murine model of MSU-induced acute gouty arthritis was established for in vivo validation. PRDM1 was highly expressed while SIRT2 poorly expressed in patients with acute gouty arthritis. Loss of PRDM1 could reduce NLRP3 inflammasome and mature IL-1β levels and downregulate inflammatory cytokines in macrophages, which contributed to protection against acute gouty arthritis. Furthermore, results showed that PRDM1 could inhibit SIRT2 expression via binding to the deacetylase SIRT2 promoter. Finally, the in vivo experiments demonstrated that PRDM1 increased NLRP3 inflammasome and mature IL-1β through transcriptional inhibition of SIRT2, whereby aggravating MSU-induced acute gouty arthritis. To sum up, PRDM1 increased NLRP3 inflammasome through inhibiting SIRT2, consequently aggravating MSU-induced acute gouty arthritis.

Modulation of PPARα-thermogenesis gut microbiota interactions in obese mice administrated with zingerone.

This study aimed to uncover the potential effects of zingerone (ZIN), one of the bioactive compounds in ginger, on the development of obesity as well as the mechanisms responsible for these effects in C57BL/6J mice fed with a high-fat diet (HFD). Supplementation with 0.2% (wt/wt) zingerone for 16 weeks significantly reduced the final body weight, liver weight, and epididymal white adipose tissue (eWAT) weight without changing the food intake of the mice when compared with the HFD group. The hyperlipidemia of HFD-fed mice was ameliorated after zingerone administration, including decreased plasma triacylglycerol (TG) and total cholesterol (TC) level. The lipid content in liver was lower and the adipocyte size in eWAT and inguinal white adipose tissue (iWAT) was smaller in HFD + ZIN-fed mice compared with HFD group. Zingerone also binds with nuclear hormone receptor peroxisome proliferator-activated receptor alpha (PPARα) with an optimal docking energy of -7.31 kJ/mol. Uncoupling protein 1 (UCP1), PPAR-γ coactivator-1α (PGC-1α), and PR domain containing 16 (PRDM16), the downstream genes of PPAR which are related to thermogenic function of adipocytes, were significantly increased in both brown adipose tissue (BAT) and inguinal white adipose tissue (iWAT) after zingerone administration, in comparison with HFD fed mice. Zingerone intake also restructured the community composition of gut microbiota. The ratio of Firmicutes to Bacteroidetes was decreased, and the relative abundance of Akkermansia_mucinphila was increased. Zingerone can attenuate obesity and related symptoms in HFD-fed mice, probably through the modulation of PPARα-thermogenesis-gut microbiota interactions. © 2022 Society of Chemical Industry.

MiR-1275 Inhibits Human Omental Adipose-Derived Stem Cells Differentiation Toward the Beige Phenotype via PRDM16.

Beige adipocytes have recently attracted attention for their potential as new therapeutic targets in the management of obesity and related metabolic disorders. MicroRNAs (miRNAs) have been reported as transcriptional regulators or biomarkers of brown and beige adipogenesis. Nevertheless, the effects of miRNAs involved in beige differentiation of human visceral adipocytes remain to be investigated. In this study, microarray screening showed that miR-1275 was significantly decreased during the differentiation of beige adipocytes induced by human omental adipose-derived stem cells (hASCs). Overexpression of miR-1275 suppressed the "brown-like" differentiation of hASCs by inhibiting the key transcriptional factor PR domain containing 16 (PRDM16) without affecting the proliferation. Adipogenesis and mitochondrial biogenesis of beige adipocytes derived from hASCs were impaired by miR-1275 overexpression. The regulatory effect of miR-1275 was determined by direct binding to the 3'-untranslated region of PRDM16, which was demonstrated by a dual-luciferase assay. Taken together, this study identified miR-1275 as a negative regulator of beige cell development in hASCs by inhibiting PRDM16. Thus, miR-1275 might be a potential target in the management of visceral obesity and related metabolic diseases.