Catabolic Genes Research Articles

Polydeoxyribonucleotide ameliorates IL-1β-induced impairment of chondrogenic differentiation in human bone marrow-derived mesenchymal stem cells

Osteoarthritis (OA) is a degenerative disease of the joints, prevalent worldwide. Polydeoxyribonucleotide (PDRN) is used for treating knee OA. However, the role of PDRN in IL-1β-induced inflammatory responses in human bone marrow-derived mesenchymal stem cells (hBMSCs) remains unknown. Here, we investigated the role of PDRN in IL-1β-induced impairment of chondrogenic differentiation in hBMSCs. hBMSCs treated with PDRN showed a large micromass, enhanced safranin O and alcian blue staining intensity, and increased expression of chondrogenic genes in IL-1β-induced inflammatory responses, in addition to regulation of catabolic and anabolic genes. In addition, PDRN treatment suppressed the expression of inflammatory cytokines and mitigated IL-1β-induced apoptosis in hBMSCs. Mechanistically, PDRN treatment increased the formation of cyclic adenosine monophosphate (cAMP) and upregulated the phosphorylation of cAMP-dependent protein kinase A (PKA)/cAMP response element binding protein (CREB) through the adenosine A2A receptor in hBMSCs and thus blocked the nuclear factor kappa-light-chain-enhancer of activated B cell (NF-κB) signaling pathway. Thus, IL-1β-induced expression of inflammatory cytokines in hBMSCs was directly reduced by adenosine A2A receptor activation. Based on our results, we suggest that PDRN may be a promising MSC-based therapeutic agent for OA.

Combination of maleic hydrazide and coumarin inhibits rice seed germination involving reactive oxygen species accumulation, ABA metabolism and starch degradation

Pre-harvest sprouting (PHS) in cereal crops is a prevalent phenomenon that impacts grain yield and quality. Several PHS inhibitory compounds were screened and identified in previous studies, such as eugenol (EUG), maleic hydrazide (MH), coumarin (COU), etc. However, few studies have focused on the combination of PHS inhibitors, and the inhibitory mechanism remains unclear. Here, through combination tests of EUG, MH, and COU, the optimal combination of PHS inhibitors was selected as MH 20 mg L−1 + COU 100 mg L−1, which presented the lowest germination percentages. The optimal combination treatment significantly decreased the germination rate, α-amylase activity, content of soluble sugar and soluble protein, enhanced ABA content and the activity of superoxide dismutase (SOD) and peroxidase (POD), inhibited the production of superoxide anion (O2−) and hydrogen peroxide, and reduced the content of malondialdehyde (MDA); conversely, this trend is precisely the opposite in normal germination. Furthermore, gene expression analysis revealed that the optimal combination of MH and COU significantly decreased the expression level of OsAmy1A and OsAmy3D at 12 and 48 h after imbibition (HAI); and promoted the expression of OsRbohs (OsRbohA, OsRbohC, OsRbohD, OsRbohE, OsRbohH) and ABA biosynthetic genes OsNCED1, OsNCED2, and OsNCED5, especially OsNCED2 at 12 HAI, but down-regulated expression of OsRbohs and ABA catabolic genes OsABA8ox1-3 at 48 HAI. These results demonstrated that the delay in seed germination induced by MH and COU involved in ROS, ABA, and sugars; the optimal combination of MH and COU inhibited the germination process by promoting ABA biosynthesis and reducing ABA catabolism, and restraining the α-amylase activity to lower soluble sugar content. Intriguingly, although the expression of OsRbohs, which play a crucial role in generating ROS, increased in early imbibition (12h), the activity of the antioxidant enzymes SOD and POD also increased with the optimal combination treatment of MH and COU, which lead to the delay in ROS accumulation and inhibition of germination. These results have deepened our understanding of the regulatory mechanism of PHS inhibitors and provided theoretical support for the application of MH and COU in preventing sprouting before crop harvesting.

Development of a novel rabbit model for femoroacetabular impingement through surgically induced acetabular overcoverage.

There is a lack of validated small animal models for femoroacetabular impingement (FAI) that induce intra-articular lesions and cause osteoarthritis (OA) progression. The gene expression profile of articular cartilage in patients with FAI has not been characterized in animal studies. The purpose of this study is to describe a novel rabbit model for FAI with validated induction of intra-articular lesions and OA progression and to characterize the gene expression pattern in impinged cartilage using this model. Thirty 6-month-old New Zealand White rabbits underwent unilateral endobutton implant placement at the acetabular rim to surgically create overcoverage. Radiological assessment confirmed secure placement of endobutton at the acetabular rim for all operated hips with a mean alteration in lateral center-edge angle (ΔLCEA) of 16.2 ± 6.6°. Gross inspection revealed secondary cartilage injuries in the anterosuperior region of the femoral head for the operated hips. Cartilage injuries were shown to exacerbate with increased impingement duration, as demonstrated by the modified Outerbridge scores and Mankin scores. Immunostaining and quantitative real-time polymerase chain reaction revealed elevated expression of inflammatory, anabolic and catabolic genes in impinged cartilage. RNA sequencing analysis of cartilage tissue revealed a distinct transcriptome profile and identified C-KIT, CD86, and CD68 as central markers. Our study confirmed that the novel rabbit FAI model created acetabular overcoverage and produced articular cartilage injury at the impingement zone. Cartilage from the impingement zone demonstrated a heightened metabolic state, corroborating with the gene expression pattern observed in patients with FAI.

Identification of Catabolic Genes Involved in the Degradation of Used Engine Lubricant- Contaminated Soil by Lysinibacillus odysseyi and Bacillus sp. (in: firmicutes)

This study aimed to identify selected catabolic genes in two indigenous hydrocarbon-degrading bacteria involved in the biodegradation of used engine lubricant-contaminated soil. Used engine lubricant-contaminated and uncontaminated soil samples were collected, and their physicochemical characteristics were evaluated. The results indicated that water holding capacity, potassium, nitrogen, and phosphate were higher in used lubricant-uncontaminated soil than in used lubricant-contaminated soil but vice versa for pH, total carbon, cation exchange, organic carbon, nickel, and lead levels. Culturable heterotrophic and hydrocarbon-utilizing bacterial counts were carried out on both Nutrient agar and Mineral Salt Medium (MSM) amended with used engine lubricant. The counts for heterotrophic bacteria (3.8×108±0.21 cfu/gm) were higher than that of hydrocarbon-utilizing bacteria (2.2×108±0.15 cfu/gm). All isolated bacteria (16) underwent screening for hydrocarbon degradation potential. Lysinibacillus odysseyi and Bacillus sp (in: firmicutes) emerged as the best oil degraders. Further screening of the chromosomal and plasmid DNA of the two bacteria was done to determine the presence and location of some selected catabolic genes (NidA, AlkB, NahH, NahAC, and Alma). The presence of Alkane monooxygenase (AlkB) and Naphthalene dioxygenase (NahAC) genes was confirmed in both isolates, while Pyrene dioxygenase (NidA) was confirmed in Bacillus sp. (in: firmicutes) only. The location of AlkB was confirmed to be both plasmid and chromosome, while NidA and NahAC genes were confirmed to be the plasmid. In conclusion, the soil contaminated with used engine lubricant contained indigenous bacteria, Lysinibacillus odysseyi, and Bacillus sp. (in: firmicutes), the two bacteria with the highest degradation potential, contained catabolic genes, monooxygenase (AlkB), NidA, and dioxygenase (NahAC). Therefore, they are effectively used as engine lubricant degraders, and the possibility of horizontal gene transfer can be used in important industrial applications and is recommended for the bioremediation of petroleum compounds.

Changes in Skeletal Muscle Atrophy over Time in a Rat Model of Adenine-Induced Chronic Kidney Disease

This study evaluated changes over time in skeletal muscle atrophy, expressions of skeletal muscle anabolic and catabolic genes, and mitochondrial activity by skeletal muscle type in an adenine-induced chronic kidney disease (CKD) model. A CKD model was successfully established by feeding male Wistar rats a 0.75% adenine diet for 4 weeks starting at 8 weeks of age. Control and CKD groups were sacrificed at 12 and 20 weeks of age. The back muscles were analyzed histologically, and succinate dehydrogenase (SDH) staining was performed to evaluate mitochondrial activity. Gene expressions of myogenic determination gene number 1 and myogenin as indicators of muscle anabolism, atrogin-1 and muscle RING-finger protein-1 (MuRF1) as indicators of muscle catabolism, and peroxisome proliferator-activated receptor-γ coactivator-1-α as a marker of mitochondrial biogenesis were assessed. Type I and type II muscle cross-sectional areas (CSAs) were decreased at 12 weeks, but type I muscle CSA was recovered at 20 weeks. SDH staining was lower in CKD than in control rats at 12 weeks, but no significant difference was observed at 20 weeks. Increased expressions of myogenin, atrogin-1, and MuRF-1 were observed only at 12 weeks, but no differences were observed at 20 weeks. The adenine-induced CKD rat model appears to show changes in muscle atrophy over time.

Loss of glycerol catabolism confers carbon-source-dependent artemisinin resistance in Mycobacterium tuberculosis.

In view of the urgent need for new antibiotics to treat human infections caused by multidrug-resistant pathogens, drug repurposing is gaining strength due to the relatively low research costs and shorter clinical trials. Such is the case of artemisinin, an antimalarial drug that has recently been shown to display activity against Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis. To gain insight into how Mtb is affected by artemisinin, we used RNAseq to assess the impact of artemisinin on gene expression profiles, revealing the induction of several efflux pumps and the KstR2 regulon. To anticipate the artemisinin resistance-conferring mutations that could arise in clinical Mtb strains, we performed an in vitro evolution experiment in the presence of lethal concentrations of artemisinin. We obtained artemisinin-resistant isolates displaying different growth kinetics and drug phenotypes, suggesting that resistance evolved through different pathways. Whole-genome sequencing of nine isolates revealed alterations in the glpK and glpQ1 genes, both involved in glycerol metabolism, in seven and one strains, respectively. We then constructed a glpK mutant and found that loss of glpK increases artemisinin resistance only when glycerol is present as a major carbon source. Our results suggest that mutations in glycerol catabolism genes could be selected during the evolution of resistance to artemisinin when glycerol is available as a carbon source. These results add to recent findings of mutations and phase variants that reduce drug efficacy in carbon-source-dependent ways.

Small extracellular vesicles derived from synovial fibroblasts contain distinct miRNA profiles and contribute to chondrocyte damage in osteoarthritis

BackgroundSmall extracellular vesicles (sEV) derived from synovial fibroblasts (SF) represent a novel molecular mechanism regulating cartilage erosion in osteoarthritis (OA). However, a comprehensive evaluation using disease relevant cells has not been undertaken. The aim of this study was to isolate and characterise sEV from OA SF and to look at their ability to regulate OA chondrocyte effector responses relevant to disease. Profiling of micro (mi) RNA signatures in sEV and parental OA SF cells was performed.MethodsSF and chondrocytes were isolated from OA synovial membrane and cartilage respectively (n = 9). sEV were isolated from OA SF (± IL-1β) conditioned media by ultracentrifugation and characterised using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Particle size was confirmed by nanoparticle tracking analysis (NTA). sEV regulation of OA chondrocyte and cartilage effector response was evaluated using qPCR, ELISA and sulphated glycosaminoglycan assay (sGAG). RNA-sequencing was used to establish miRNA signatures in isolated sEV from OA SF.ResultsOA SF derived sEV were readily taken up by OA chondrocytes, with increased expression of the catabolic gene MMP 13 (p < 0.01) and decreased expression of the anabolic genes aggrecan and COL2A1 (p < 0.01) observed. Treatment with sEV derived from IL-1β stimulated OA SF significantly decreased expression of aggrecan and COL2A1 (p < 0.001) and increased SOX 9 gene expression (p < 0.05). OA chondrocytes cultured with sEV from either non-stimulated or IL-1β treated OA SF, resulted in a significant increase in the secretion of IL-6, IL-8 and MMP-3 (p < 0.01). Cartilage explants cultured with sEV from SF (± IL-1β) had a significant increase in the release of sGAG (p < 0.01). miRNA signatures differed between parental SF cells and isolated sEV. The recently identified osteoclastogenic regulator miR182, along with miR4472-2, miR1302-3, miR6720, miR6087 and miR4532 were enriched in sEV compared to parental cells, p < 0.01. Signatures were similar in sEVs derived from non-stimulated or IL-1β stimulated SF.ConclusionsOA SF sEV regulate chondrocyte inflammatory and remodelling responses. OA SF sEV have unique signatures compared to parental cells which do not alter with IL-1β stimulation. This study provides insight into a novel regulatory mechanism within the OA joint which could inform future targeted therapy.

Effects of refeeding with low- or high-carbohydrate diets on intermediary carbohydrate metabolism in juvenile and adult Nile tilapia

Generally, energy expenditure and compensation according to food deprivation and refeeding often occur along the life cycle of farmed-raised fish. Fasting and refeeding are also hypothesised to modulate carbohydrate metabolism particularly for herbivorous and/or omnivorous. This study aims to investigate the effects of short-term fasting and subsequent refeeding with high or low−carbohydrate diets on the intermediary carbohydrate metabolism of juvenile and adult Nile tilapia (Oreochromis niloticus) which is known to be a good user of carbohydrate as an energy source. Fish were fasted for 4 days and subsequently refed with either a low carbohydrate and high protein (LC/HP) or high carbohydrate and low protein (HC/LP) diet for 4 days. Our results showed that 4 days of refeeding with either one of the diets could compensate for weight loss due to fasting. Thus, we investigated the effects of a 4-day-refeeding strategy and different carbohydrate−refeeding diets on plasma metabolites, nutrient composition, and glucose and its related metabolism in the liver and muscle of adult fish. Refeeding had similar effects in adults and juveniles and induced modulations to the intermediary metabolism: (1) refeeding with the HC/LP diet elevated plasma glucose levels; (2) refeeding with both diets increased triglyceride levels in the plasma, liver, and muscle, but the effect of the HC/LP diet was superior; (3) refeeding elevated plasma cholesterol levels in adults, irrespective of diet; (4) refeeding with both diets increased hepatic lipid levels in juveniles, with stronger effects observed in those fed the HC/LP diet, and refeeding with the HC/LP diet elevated hepatic lipid levels in adults; (5) refeeding with both diets increased the plasma protein content, but the effect of the LC/HP diet was superior; (6) refeeding with the LC/HP diet increased hepatic protein content in adults; and (7) refeeding with both diets increased hepatic glycogen levels, but the effect of the HC/LP diet was superior. Additionally, in juveniles and adults, refeeding with the HC/LP diet upregulated the expression of glycolytic genes in the liver and muscle, lipogenic genes in the liver, and glucose transport genes. Moreover, refeeding with the HC/LP diet downregulated the expression of gluconeogenic and amino acid catabolism genes in the liver and amino acid catabolism genes in the muscle. Collectively, the effect of short-term refeeding with a high carbohydrate diet on intermediary metabolism resembled that of long-term feeding, supporting the hypothesis that Nile tilapia, an omnivorous fish, is highly responsive to dietary carbohydrates.

Efficacy and safety of SKCPT in patients with knee osteoarthritis: A multicenter, randomized, double-blinded, active-controlled phase III clinical trial

Ethnopharmacological relevanceOsteoarthritis (OA) is the most prevalent type of arthritis worldwide and a leading cause of years lost to pain and disability. Among the current pharmacological treatments for OA, symptomatic slow-acting drugs for OA (SYSADOA) induce pain relief and aim to improve joint function by relieving inflammation while causing fewer gastrointestinal and cardiovascular adverse events than non-steroidal anti-inflammatory drugs (NSAIDs). SKCPT is a herbal SYSADOA formulated from Clematis mandshurica, Trichosanthes kirilowii, and Prunella vulgaris powdered extracts. This preparation has been shown to induce cartilage protection and anti-inflammatory effects in preclinical studies and inhibit glycosaminoglycan degradation and catabolic gene expression in human OA chondrocytes and cartilage. Aim of the studyWe aimed to evaluate the non-inferiority of SKCPT to celecoxib and safety for treating knee OA. Materials and methodsThis multicenter, randomized, double-blind, phase III clinical trial enrolled adults with primary knee OA who were randomized (1:1) to SKCPT 300 mg twice daily or celecoxib 200 mg once daily for 12 weeks. ResultsIn total, 278 patients were assigned to treatment (SKCPT, 136; celecoxib, 142) for approximately 12 weeks. The primary endpoint was the mean change of Korean Western Ontario and McMaster Universities Osteoarthritis Index (K-WOMAC) pain subscale scores from baseline to Day 84. The mean change (least squares [LS] mean ± standard error) from baseline to Day 84 was −23.74 ± 1.48 for SKCPT and −25.88 ± 1.44 for celecoxib. The two-sided 95% confidence interval of the difference (LS mean) between groups was [−1.94, 6.20], confirming that the upper limit was less than the non-inferiority margin of 10. Additionally, there were no significant differences in the secondary endpoints (mean changes of K-WOMAC pain, physical, stiffness subscale, and total score, and the frequency and number of doses of rescue medications) between groups at all time points. Differences between groups in adverse events and adverse drug reactions were not significant, and no serious adverse events occurred. ConclusionsSKCPT efficacy was non-inferior, and its safety profile was similar, to celecoxib. Building on previous results showing that SYSADOA reduce NSAID intake, the present results suggest that the SYSADOA SKCPT could effectively replace NSAIDs in knee OA treatment while avoiding long-term side effects.

OsFAD1-OsMYBR22 modulates clustered spikelet through regulating BRD3 in rice.

The phenotype of rice clustered spikelet mutants results from the upregulation of the FAD/NAD(P)-binding oxidoreductase family gene OsFAD1. Enhanced interaction between OsFAD1 and the transcription factor OsMYBR22 leads to the upregulation of the spikelet clustering-related BR catabolic gene BRD3.

NAC Transcription Factor PpNAP4 Promotes Chlorophyll Degradation and Anthocyanin Synthesis in the Skin of Peach Fruit.

Chlorophyll (Chl) catabolism and anthocyanin synthesis play pivotal roles in determining the final skin color of fruits during maturation. However, in peach (Prunus persica) fruit, the regulatory mechanism governing skin color, especially the Chl catabolism, remains largely elusive. In this study, we identified ten Chl catabolic genes (CCGs), with PpSGR emerging as a key regulator in Chl degradation in peaches. Furthermore, a NAC-like, activated by AP3/P1 (NAP) transcription factor (TF), PpNAP4, was identified as a positive modulator of Chl breakdown. PpNAP4 induced the expression of PpSGR and other CCGs, including PpPPH, PpPAO, and PpTIC55-2, by directly binding to their promoters. Overexpression of PpNAP4 resulted in a heightened expression of these genes and accelerated Chl degradation. Notably, PpNAP4 also positively regulated the expression of PpANS and PpMYB10.1, one key structural gene and a core transcriptional regulator of anthocyanin synthesis, thereby contributing to fruit coloration. In summary, our findings elucidate that PpNAP4 serves as a pivotal regulator in determining the final skin color of peach by orchestrating Chl degradation and anthocyanin accumulation through direct activation of multiple CCGs and anthocyanin related genes.

Overexpression of OsRbohH Enhances Heat and Drought Tolerance through ROS Homeostasis and ABA Mediated Pathways in Rice (Oryza sativa L.).

Respiratory burst oxidase homologs (Rbohs) are the primary producers of reactive oxygen species (ROS), which have been demonstrated to play critical roles in plant responses to abiotic stress. Here, we explored the function of OsRbohH in heat and drought stress tolerance by generating overexpression lines (OsRbohH-OE). OsRbohH was highly induced by various abiotic stress and hormone treatments. Compared to wild-type (WT) controls, OsRbohH-OE plants exhibited enhanced tolerance to heat and drought, as determined by survival rate analyses and total chlorophyll content. Histochemical staining revealed that OsRbohH-OE accumulated less ROS. This is consistent with the observed increase in catalase (CAT) and peroxidase (POD) activities, as well as a reduced electrolyte leakage rate and malondialdehyde (MDA) content. Moreover, OsRbohH-OE exhibited enhanced sensitivity to exogenous abscisic acid (ABA), accompanied by altered expression levels of ABA synthesis and catabolic genes. Further analysis indicated that transgenic lines had lower transcripts of ABA signaling-related genes (OsDREB2A, OsLEA3, OsbZIP66, and OsbZIP72) under heat but higher levels under drought than WT. In conclusion, these results suggest that OsRbohH is a positive regulator of heat and drought tolerance in rice, which is probably performed through OsRbohH-mediated ROS homeostasis and ABA signaling.

The G protein-coupled receptor ADGRG6 maintains mouse growth plate homeostasis through IHH signaling.

The cartilage growth plate is essential for maintaining skeletal growth; however, the mechanisms governing postnatal growth plate homeostasis are still poorly understood. Using approaches of molecular mouse genetics and spatial transcriptomics applied to formalin-fixed, paraffin-embedded tissues, we show that ADGRG6/GPR126, a cartilage-enriched adhesion G protein-coupled receptor (GPCR), is essential for maintaining slow-cycling resting zone cells, appropriate chondrocyte proliferation and differentiation, and growth plate homeostasis in mice. Constitutive ablation of Adgrg6 in osteochondral progenitor cells with Col2a1Cre leads to a shortened resting zone, formation of cell clusters within the proliferative zone, and an elongated hypertrophic growth plate, marked by limited expression of parathyroid hormone-related protein (PTHrP) but increased Indian Hedgehog (IHH) signaling throughout the growth plate. Attenuation of smoothened-dependent hedgehog signaling restored the Adgrg6 deficiency-induced expansion of hypertrophic chondrocytes, confirming that IHH signaling can promote chondrocyte hypertrophy in a PTHrP-independent manner. In contrast, postnatal ablation of Adgrg6 in mature chondrocytes with AcanCreERT2, induced after the formation of the resting zone, does not affect PTHrP expression but causes an overall reduction of growth plate thickness marked by increased cell death specifically in the resting zone cells and a general reduction of chondrocyte proliferation and differentiation. Spatial transcriptomics reveals that ADGRG6 is essential for maintaining chondrocyte homeostasis by regulating osteogenic and catabolic genes in all the zones of the postnatal growth plates, potentially through positive regulation of SOX9 expression. Our findings elucidate the essential role of a cartilage-enriched adhesion GPCR in regulating cell proliferation and hypertrophic differentiation by regulation of PTHrP/IHH signaling, maintenance of slow-cycle resting zone chondrocytes, and safeguarding chondrocyte homeostasis in postnatal mouse growth plates.

Unravelling the role of proline in glyphosate-mediated toxicity - tolerance mechanism or stress signal?

Glyphosate (GLY), the most widely used herbicide, has been regarded as an emergent environmental contaminant due to its constant and cumulative use, with potential harm to non-target organisms, such as crops, disrupting cells' redox balance. Therefore, plants need to fine-tune their antioxidant (AOX) mechanisms to thrive under GLY-contaminated environments. Proline overaccumulation is a common response in plants exposed to GLY, yet its role in GLY-induced toxicity remains unclear. Thus, this study explores whether Pro overaccumulation in response to GLY is perceived as a downstream tolerance mechanism or an early-warning stress signal. To investigate this, Arabidopsis thaliana T-DNA mutant lines for Pro biosynthetic (P5CS1) and catabolic genes (ProDH) were used and screened for their GLY susceptibility. Upon seedlings' exposure to GLY (0.75 mg L-1) for 14 days, the herbicide led to reduced biomass in all genotypes, accompanied by Pro overaccumulation. Mutants with heightened Pro levels (prodh) exhibited the greatest biomass reduction, increased lipid peroxidation (LP), and hydrogen peroxide (H2O2) levels, accompanied by a compromised performance of the AOX system. Conversely, p5cs1-4, mutants with lower Pro levels, demonstrated an enhanced AOX system activation, not only with increased levels of glutathione (GSH) and ascorbate (AsA), but also with increased activity of both ascorbate peroxidase (APX) and catalase (CAT). These findings suggest that Pro overaccumulation under GLY exposure is associated with stress sensitivity rather than tolerance, highlighting its potential as an early-warning signal for GLY toxicity in non-target plants and for detecting weed resistance.

Disruption of branched-chain amino acid homeostasis promotes the progression of DKD via enhancing inflammation and fibrosis-associated epithelial-mesenchymal transition

Background and aimsThe disrupted homeostasis of branched-chain amino acids (BCAAs, including leucine, isoleucine, and valine) has been strongly correlated with diabetes with a potential causal role. However, the relationship between BCAAs and diabetic kidney disease (DKD) remains to be established. Here, we show that the elevated BCAAs from BCAAs homeostatic disruption promote DKD progression unexpectedly as an independent risk factor. Methods and resultsSimilar to other tissues, the suppressed BCAAs catabolic gene expression and elevated BCAAs abundance were detected in the kidneys of type 2 diabetic mice and individuals with DKD. Genetic and nutritional studies demonstrated that the elevated BCAAs from systemic disruption of BCAAs homeostasis promoted the progression of DKD. Of note, the elevated BCAAs promoted DKD progression without exacerbating diabetes in the animal models of type 2 DKD. Mechanistic studies demonstrated that the elevated BCAAs promoted fibrosis-associated epithelial-mesenchymal transition (EMT) by enhancing the activation of proinflammatory macrophages through mTOR signaling. Furthermore, pharmacological enhancement of systemic BCAAs catabolism using small molecule inhibitor attenuated type 2 DKD. Finally, the elevated BCAAs also promoted DKD progression in type 1 diabetic mice without exacerbating diabetes. ConclusionBCAA homeostatic disruption serves as an independent risk factor for DKD and restoring BCAA homeostasis pharmacologically or dietarily represents a promising therapeutic strategy to ameliorate the progression of DKD.

Involvement of BcNAC083 in 1-MCP-induced delayed yellowing of pak choi (Brassica rapa subsp. Chinensis) through the regulation of reactive oxygen species metabolism and inhibition of major chlorophyll catabolic genes

Leaf yellowing is a typical senescence feature in postharvest pak choi. Plant-specific NAC transcription factors (TFs) are crucial regulators of plant senescence. In this study, a senescence-related NAC TF, BcNAC083, was investigated to identify its transcriptional regulation effects on the yellowing of pak choi by treatment with 1-methylcyclopropene (1-MCP). Applying 5.0 µL L–1 1-MCP alleviated yellowing and maintained a low respiration rate, high chlorophyll content, and relatively complete chloroplast structure in pak choi during storage. However, 10 μL L–1 ethylene accelerated yellowing, as demonstrated by the higher respiration rate, lower chloroplast structural integrity and chlorophyll content. In contrast to ethylene treatment, 1-MCP suppressed the activity of the reactive oxygen species (ROS) metabolism-related enzymes superoxide dismutase (SOD), catalase (CAT), ascorbic peroxidase (APX), and lipoxygenase (LOX), and correspondingly reduced superoxide anion (O2·–), hydrogen peroxide (H2O2), and malondialdehyde (MDA) accumulation. 1-MCP treatment also suppressed the transcript levels of ROS metabolic genes, including BcRBOHC, BcRBOHD, BcSOD, BcCAT, BcAPX, and BcLOX, and inhibited the activity of the chlorophyll catabolic enzymes chlorophyllase (CLH), Mg-de-chelatase, and pheophytin pheophorbide hydrolase (PPH) and transcript levels of associated genes, including BcCLH1/2, BcPPH1/2, BcPAO, BcNYC1, BcSGR1/2, BcHCAR, BcRCCR, and BcCAO. The expression of BcNAC083 was probably induced by ROS and was downregulated by 1-MCP and upregulated by ethylene. Molecular biology experiments determined that BcNAC083 bound directly to and activated the promoters of the chlorophyll metabolism-related genes BcCLH1, BcPPH1, BcNYC1, and BcHCAR. Importantly, transient overexpression of BcNAC083 stimulated the endogenous genes (NbCLH1, NbPPH1, NbNYC1, and NbHCAR) expression in tobacco leaves, resulting in rapid chlorophyll breakdown and leaf degreening. Treatment with 1-MCP may alleviated the yellowing of pak choi by inhibiting ROS accumulation and the transcriptional regulation of BcNAC083, which had positive regulatory effects on major chlorophyll metabolic genes.

Contrasted NCED gene expression across conifers with rising and peaking abscisic acid responses to drought

Conifer trees have diverse strategies to cope with drought. They accumulate the plant hormone abscisic acid (ABA) following a range of profiles from constantly rising to peaking and falling (R- and P-type) with direct effect on foliar transpiration. The molecular basis of this adaptive diversification among species is largely unknown. Here, we analysed the sequences of candidate ABA biosynthesis and catabolism genes and monitored their expression in response to intensifying drought. We studied young trees from Cupressaceae, Pinaceae, and Taxaceae under controlled drought conditions and compared changes in water status, ABA profiles and gene-specific transcript levels. Our data indicate that R-type and P-type ABA profiles may be controlled by divergent expression of genes involved in the biosynthetic and catabolic pathways of ABA, respectively, and emphasize a key role of nine-cis-epoxycarotenoid dioxygenases (NCED) genes. Our results open the doors to understanding the molecular basis of contrasted drought response strategies across conifer taxa, which we expect will help foresters grow more drought-resilient trees.

The Expression of Toll-like Receptors in Cartilage Endplate Cells: A Role of Toll-like Receptor 2 in Pro-Inflammatory and Pro-Catabolic Gene Expression.

The vertebral cartilage endplate (CEP), crucial for intervertebral disc health, is prone to degeneration linked to chronic low back pain, disc degeneration, and Modic changes (MC). While it is known that disc cells express toll-like receptors (TLRs) that recognize pathogen- and damage-associated molecular patterns (PAMPs and DAMPs), it is unclear if CEP cells (CEPCs) share this trait. The CEP has a higher cell density than the disc, making CEPCs an important contributor. This study aimed to identify TLRs on CEPCs and their role in pro-inflammatory and catabolic gene expression. Gene expression of TLR1-10 was measured in human CEPs and expanded CEPCs using quantitative polymerase chain reaction. Additionally, surface TLR expression was measured in CEPs grouped into non-MC and MC. CEPCs were stimulated with tumor necrosis factor alpha, interleukin 1 beta, small-molecule TLR agonists, or the 30 kDa N-terminal fibronectin fragment. TLR2 signaling was inhibited with TL2-C29, and TLR2 protein expression was measured with flow cytometry. Ex vivo analysis found all 10 TLRs expressed, while cultured CEPCs lost TLR8 and TLR9 expression. TLR2 expression was significantly increased in MC1 CEPCs, and its expression increased significantly after pro-inflammatory stimulation. Stimulation of the TLR2/6 heterodimer upregulated TLR2 protein expression. The TLR2/1 and TLR2/6 ligands upregulated pro-inflammatory genes and matrix metalloproteases (MMP1, MMP3, and MMP13), and TLR2 inhibition inhibited their upregulation. Endplate resorptive capacity of TLR2 activation was confirmed in a CEP explant model. The expression of TLR1-10 in CEPCs suggests that the CEP is susceptible to PAMP and DAMP stimulation. Enhanced TLR2 expression in MC1, and generally in CEPCs under inflammatory conditions, has pro-inflammatory and pro-catabolic effects, suggesting a potential role in disc degeneration and MC.

RhMYC2 controls petal size through synergistic regulation of jasmonic acid and cytokinin signaling in rose.

Petal size is determined by cell division and cell expansion. Jasmonic acid (JA) has been reported to be associated with floral development, but its regulatory mechanism affecting petal size remains unclear. Here, we reveal the vital role of JA in regulating petal size and the duration of the cell division phase via the key JA signaling component RhMYC2. We show that RhMYC2 expression is induced by exogenous treatment with methyl jasmonate and decreases from stage 0 to stage 2 of flower organ development, corresponding to the cell division phase. Furthermore, silencing RhMYC2 shortened the duration of the cell division phase, ultimately accelerating flowering opening and resulting in smaller petals. In addition, we determined that RhMYC2 controls cytokinin homeostasis in rose petals by directly activating the expression of the cytokinin biosynthetic gene LONELY GUY3 (RhLOG3) and repressing that of the cytokinin catabolism gene CYTOKININ OXIDASE/DEHYDROGENASE6 (RhCKX6). Silencing RhLOG3 shortened the duration of the cell division period and produced smaller petals, similar to RhMYC2 silencing. Our results underscore the synergistic effects of JA and cytokinin in regulating floral development, especially for petal size in roses.

Different Roles of Dioxin-Catabolic Plasmids in Growth, Biofilm Formation, and Metabolism of Rhodococcus sp. Strain p52.

Microorganisms harbor catabolic plasmids to tackle refractory organic pollutants, which is crucial for bioremediation and ecosystem health. Understanding the impacts of plasmids on hosts provides insights into the behavior and adaptation of degrading bacteria in the environment. Here, we examined alterations in the physiological properties and gene expression profiles of Rhodococcus sp. strain p52 after losing two conjugative dioxin-catabolic megaplasmids (pDF01 and pDF02). The growth of strain p52 accelerated after pDF01 loss, while it decelerated after pDF02 loss. During dibenzofuran degradation, the expression levels of dibenzofuran catabolic genes on pDF01 were higher compared to those on pDF02; accordingly, pDF01 loss markedly slowed dibenzofuran degradation. It was suggested that pDF01 is more beneficial to strain p52 under dibenzofuran exposure. Moreover, plasmid loss decreased biofilm formation, especially after pDF02 loss. Transcriptome profiling revealed different pathways enriched in upregulated and downregulated genes after pDF01 and pDF02 loss, indicating different adaptation mechanisms. Based on the transcriptional activity variation, pDF01 played roles in transcription and anabolic processes, while pDF02 profoundly influenced energy production and cellular defense. This study enhances our knowledge of the impacts of degradative plasmids on native hosts and the adaptation mechanisms of hosts, contributing to the application of plasmid-mediated bioremediation in contaminated environments.