Two cases of venous thromboembolism in siblings after splenectomy due to a novel PROC gene mutation.

BACKGROUND: Venous thromboembolism(VTE)is a common multifactorial disease. Anticoagulant protein deficiency is the most usual hereditary thrombophilia in the Chinese people, which includes protein C(PC), protein S and antithrombin deficiencies. CASE PRESENTATION: A retrospective analysis was conducted on clinical manifestations, laboratory tests, genetic information, and other relevant data of siblings diagnosed with VTE in 2020 at the Department of Pediatrics of Shenzhen Second People's Hospital. The proband, a 12-year-old female, was admitted to the hospital in December 2020 with a complaint of pain in the left lower limb for four days. The examination found that the PC activity was 53%, and B-ultrasound showed bilateral thrombosis of the great saphenous vein in the thigh segment. The proband's younger brother, a 10-year-old male, was admitted to the hospital in January 2021 due to right lower limb pain for two weeks. PC activity is 40%. B-ultrasound showed superficial venous thrombosis in the left lower limb and upper limb. Both siblings suffered from thalassemia and underwent splenectomy before recurrent thrombosis occurred. The proband's mother was asymptomatic, and her PC activity was 45%. Both cases were treated with warfarin anticoagulation, and their symptoms improved. The proband's mother was found to have a heterozygous mutation at this locus through Sanger sequencing. CONCLUSION: Protein C deficiency should be considered for venous thromboembolism in childhood. The heterozygous mutation 1204 A > G in PROC exon 9 in this family is reported for the first time.

Phenotypic Investigation and RNA-seq of KN1 Involved in Leaf Angle Formation in Maize (Zea mays L.).

Leaf angle (LA) is one of the core agronomic traits of maize, which controls maize yield by affecting planting density. Previous studies have shown that the KN1 gene is closely related to the formation of maize LA, but its specific mechanism has not been fully studied. In this study, phenotype investigation and transcriptomic sequencing were combined to explore the mechanism of LA changes in wild type maize B73 and mutant kn1 under exogenous auxin (IAA) and abscisic acid (ABA) treatment. The results showed that the effect of exogenous phytohormones had a greater impact on the LA of kn1 compared to B73. Transcriptome sequencing showed that genes involved in IAA, gibberellins (GAs) and brassinosteroids (BRs) showed different differential expression patterns in kn1 and B73. This study provides new insights into the mechanism of KN1 involved in the formation of maize LA, and provides a theoretical basis for breeding maize varieties with suitable LA.

Epigenetic marks or not? The discovery of novel DNA modifications in eukaryotes.

DNA modifications add another layer of complexity to the eukaryotic genome to regulate gene expression, playing critical roles as epigenetic marks. In eukaryotes, the study of DNA epigenetic modifications has been confined to 5mC and its derivatives for decades. However, rapid developing approaches have witnessed the expansion of DNA modification reservoirs during the past several years, including the identification of 6mA, 5gmC, 4mC, and 4acC in diverse organisms. However, whether these DNA modifications function as epigenetic marks requires careful consideration. In this review, we try to present a panorama of all the DNA epigenetic modifications in eukaryotes, emphasizing recent breakthroughs in the identification of novel DNA modifications. The characterization of their roles in transcriptional regulation as potential epigenetic marks is summarized. More importantly, the pathways for generating or eliminating these DNA modifications, as well as the proteins involved are comprehensively dissected. Furthermore, we briefly discuss the potential challenges and perspectives, which should be taken into account while investigating novel DNA modifications.

CXC chemokine receptor 7 ameliorates renal fibrosis by inhibiting ß-catenin signaling and epithelial-to-mesenchymal transition in tubular epithelial cells.

Renal fibrosis is a common feature of various chronic kidney diseases. However, the underlying mechanism remains poorly understood. The CXC chemokine receptor (CXCR) family plays a role in renal fibrosis; however, the detailed mechanisms have not been elucidated. In this study, we investigated the potential role of CXCR7 in mediating renal fibrosis. CXCR7 expression is decreased in unilateral ischemia-reperfusion injury (UIRI) and unilateral ureteral obstruction mouse models. Furthermore, CXCR7 was specifically expressed primarily in the Lotus Tetragonolobus Lectin-expressing segment of tubules, was slightly expressed in the peanut agglutinin-expressing segment, and was barely expressed in the Dolichos biflorus agglutinin-expressing segment. Administration of pFlag-CXCR7, an overexpression plasmid for CXCR7, significantly inhibited the activation of ß-catenin signaling and protected against the progression of epithelial-to-mesenchymal transition (EMT) and renal fibrosis in a UIRI mouse model. Using cultured HKC-8 cells, we found that CXCR7 significantly downregulated the expression of active ß-catenin and fibrosis-related markers, including fibronectin, Collagen I, and α-SMA. Furthermore, CXCR7 significantly attenuated TGF-ß1-induced changes in ß-catenin signaling, EMT and fibrosis. These results suggest that CXCR7 plays a crucial role in inhibiting the activation of ß-catenin signaling and the progression of EMT and renal fibrosis. Thus, CXCR7 could be a novel therapeutic target for renal fibrosis.

METTL1 mediated tRNA m7G modification promotes leukaemogenesis of AML via tRNA regulated translational control.

BACKGROUND: RNA modifications have been proven to play fundamental roles in regulating cellular biology process. Recently, maladjusted N7-methylguanosine (m7G) modification and its modifiers METTL1/WDR4 have been confirmed an oncogene role in multiple cancers. However, the functions and molecular mechanisms of METTL1/WDR4 in acute myeloid leukemia (AML) remain to be determined. METHODS: METTL1/WDR4 expression levels were quantified using qRT-PCR, western blot analysis on AML clinical samples, and bioinformatics analysis on publicly available AML datasets. CCK-8 assays and cell count assays were performed to determine cell proliferation. Flow cytometry assays were conducted to assess cell cycle and apoptosis rates. Multiple techniques were used for mechanism studies in vitro assays, such as northern blotting, liquid chromatography-coupled mass spectrometry (LC-MS/MS), tRNA stability analysis, transcriptome sequencing, small non-coding RNA sequencing, quantitative proteomics, and protein synthesis measurements. RESULTS: METTL1/WDR4 are significantly elevated in AML patients and associated with poor prognosis. METTL1 knockdown resulted in reduced cell proliferation and increased apoptosis in AML cells. Mechanically, METTL1 knockdown leads to significant decrease of m7G modification abundance on tRNA, which further destabilizes tRNAs and facilitates the biogenesis of tsRNAs in AML cells. In addition, profiling of nascent proteins revealed that METTL1 knockdown and transfection of total tRNAs that were isolated from METTL1 knockdown AML cells decreased global translation efficiency in AML cells. CONCLUSIONS: Taken together, our study demonstrates the important role of METTL1/WDR4 in AML leukaemogenesis, which provides a promising target candidate for AML therapy.

The CXCR4-AT1 axis plays a vital role in glomerular injury via mediating the crosstalk between podocyte and mesangial cell.

Glomeruli stand at the center of nephrons to accomplish filtration and albumin interception. Podocytes and mesangial cells are the major constituents in the glomeruli. However, their interdependency in glomerular injury has rarely been reported. Herein, we investigated the role of C-X-C chemokine receptor type 4 (CXCR4) in mediating the crosstalk between podocytes and mesangial cells. We found CXCR4 and angiotensin II (AngII) increased primarily in injured podocytes. However, type-1 receptor of angiotensin II (AT1) and stromal cell-derived factor 1α (SDF-1α), a ligand of CXCR4, were evidently upregulated in mesangial cells following the progression of podocyte injury. Ectopic expression of CXCR4 in 5/6 nephrectomy mice increased the decline of renal function and glomerular injury, accelerated podocyte injury and mesangial cell activation, and initiated CXCR4-AT1 axis signals. Additionally, treatment with losartan, an AT1 blocker, interrupted the cycle of podocyte injury and mesangial matrix deposition triggered by CXCR4. Podocyte-specific ablation of CXCR4 gene blocked podocyte injury and mesangial cell activation. In vitro, CXCR4 overexpression induced oxidative stress and renin angiotensin system (RAS) activation in podocytes, and triggered the communication between podocytes and mesangial cells. In cultured mesangial cells, AngII treatment induced the expression of SDF-1α, which was secreted into the supernatant to further promote oxidative stress and cell injury in podocytes. Collectively, these results demonstrate that the CXCR4-AT1 axis plays a vital role in glomerular injury via mediating pathologic crosstalk between podocytes and mesangial cells. Our findings uncover a novel pathogenic mechanism by which the CXCR4-AT1 axis promotes glomerular injury.

Nitenpyram biodegradation by a novel nitenpyram-degrading bacterium, Ochrobactrum sp. strain DF-1, and its novel degradation pathway.

Nitenpyram is a neonicotinoid insecticide that is commonly found in the environment. However, its biodegradation by pure cultures of bacteria has not been widely investigated and the catabolic pathway (s) for nitenpyram metabolism remain elusive. In this study, the aerobic strain DF-1, isolated from a wastewater-treatment pool contaminated with nitenpyram. The strain was designated an Ochrobactrum sp. utilizing a combination of traditional methods and molecular ones. Strain DF-1 can use nitenpyram as a sole carbon or nitrogen source for growth. In liquid medium, 100 mg·L-1 nitenpyram was metabolized to undetectable levels within 10 days. Four metabolites were found by gas chromatography-mass spectrometry (GC-MS) analyses during nitenpyram degradation. According to the aforementioned data, a partial metabolic pathway of nitenpyram was proposed of strain DF-1. Inoculation of strain DF-1 promoted nitenpyram (10 mg·kg-1) degradation in either sterile or non-sterile soil. To our knowledge, this is the first characterization of nitenpyram degradation by a specific bacterium and likely to be exploited for the remediation of nitenpyram-contaminated sites.

Exosomal PPARγ derived from macrophages suppresses LPS-induced peritonitis by negative regulation of CD14/TLR4 axis.

BACKGROUND: Intercellular communication between macrophages and peritoneal mesothelial cells (PMCs) has been suggested as a key factor regulating peritonitis development. Here, we explored whether PPARγ (peroxisome proliferator-activated receptor gamma) can be packaged into macrophage exosomes to mediate intercellular communication and regulate peritonitis. METHODS: Macrophage exosomes were isolated by ultracentrifugation and identified by nanoparticle tracking analysis and transmission electron microscopy. Proteomic analysis of macrophage-derived exosomes was performed using mass spectrometry. Co-culture models of supernatants or exosomes with PMCs, as well as a mouse peritonitis model induced by lipopolysaccharide (LPS), were employed. RESULTS:  In this study, using stable Raw264.7 cells overexpressing GFP-FLAG-PPARγ (OE-PPARγ), we found that PPARγ inhibited LPS-induced inflammatory responses in Raw264.7 cells and that PPARγ was incorporated into macrophage exosomes during this process. Overexpression of PPARγ mainly regulated the secretion of differentially expressed exosomal proteins involved in the biological processes of protein transport, lipid metabolic process, cell cycle, apoptotic process, DNA damage stimulus, as well as the KEGG pathway of salmonella infection. Using co-culture models and mouse peritonitis model, we showed that exosomes from Raw264.7 cells overexpressing PPARγ inhibited LPS-induced inflammation in co-cultured human PMCs and in mice through downregulating CD14 and TLR4, two key regulators of the salmonella infection pathway. Pretreatment of the PPARγ inhibitor GW9662 abolished the anti-inflammatory effect of exosomes from Raw264.7 OE-PPARγ cells on human PMCs. CONCLUSIONS: These results suggested that overexpression of PPARγ largely altered the proteomic profile of macrophage exosomes and that exosomal PPARγ from macrophages acted as a regulator of intercellular communication to suppress LPS-induced inflammatory responses in vitro and in vivo via negatively regulating the CD14/TLR4 axis.

Risk factors of left ventricular diastolic dysfunction in maintenance hemodialysis patients.

OBJECTIVE: To investigate the risk factors of left ventricular diastolic dysfunction in maintenance hemodialysis (MHD) patients. METHOD: We retrospectively collected data from 363 hemodialysis patients who were on dialysis for at least 3 months at January 1, 2020. According to the echocardiogram results, these patients were divided into left ventricular diastolic dysfunction (LVDD) group and non-LVDD group. The differences in basic data, cardiac structure and functiona between the two groups were analyzed. Logistic regression analysis was used to analyze the risk factors of cardiac diastolic dysfunction in MHD patients. RESULTS: Compared with the non-LVDD group, patients in the LVDD group were older, with an increased proportion of coronary heart disease, more prone to chest tightness, shortness of breath. Simultaneously, they had a significantly increased (p < 0.05) proportion of cardiac structural abnormalities such as left ventricular hypertrophy, left heart enlargement and systolic dysfunction. Multivariate logistic regression analysis showed that the risk of LVDD was significantly increased in elderly MHD patients older than 60 years (OR = 3.86, 95%CI 1.429-10.429), and left ventricular hypertrophy was also significantly associated with LVDD (OR = 2.227, 95% CI 1.383-3.586). CONCLUSION: According to research, both age and left ventricular hypertrophy are risk factors for LVDD in MHD patients. It is recommended that early intervention for LVDD should be implemented to improve the quality of dialysis and reduce the incidence of cardiovascular events in MHD patients.

Phasic regulation of the ATP/P2X7 receptor signaling pathway affects the function of antigen-presenting cells in experimental autoimmune uveitis.

Purinergic ligand-gated ion channel 7 receptor (P2X7R) is a purine type P2 receptor that is expressed on a variety of immune cells. Recent studies have shown that P2X7R signaling is required to trigger an immune response, and P2X7R antagonist-oxidized ATP (oxATP) effectively blocks P2X7R activation. In this study, we investigated the effect of phasic regulation of the ATP/P2X7R signaling pathway on antigen-presenting cells (APCs) by constructing an experimental autoimmune uveitis (EAU) disease model. Our results demonstrated that APCs isolated from the 1st, 4th, 7th and 11th days of EAU presented antigen function and could stimulate the differentiation of naive T cells. Moreover, after stimulation by ATP and BzATP (a P2X7R agonist), antigen presentation, promoting differentiation and inflammation were enhanced. The regulation of the Th17 cell response was significantly stronger than that of the Th1 cell response. In addition, we verified that oxATP blocked the P2X7R signaling pathway on APCs, attenuated the effect of BzATP, and significantly improved the adoptive transfer EAU induced by antigen-specific T cells cocultured with APCs. Our results demonstrated that at an early stage of EAU, the ATP/P2X7R signaling pathway regulation of APCs was time dependent, and the treatment of EAU could be achieved by intervening in P2X7R function on APCs.

Sirtuin 6 is a key contributor to gender differences in acute kidney injury.

Acute kidney injury (AKI) is rapidly increasing nowadays and at a high risk to progress into chronic kidney disease (CKD). Of note, men are more susceptive to AKI, suggesting gender differences in AKI patients. However, the underlying mechanisms remain largely unclear. To test it, we adopted two experimental models of AKI, including ischemia/reperfusion injury and rhabdomyolysis, which were constructed in age-matched male and female mice. We found severe damages of tubular apoptosis, mitochondrial dysfunction, and loss of renal function showing in male mice, while female mice only had very mild injury. We further tested the expression of Sirtuins, and found that female mice could preserve more Sirtuin members' expression in case of kidney damage. Among Sirtuin family, Sirtuin 6 was maximally preserved in injured kidney in female mice, suggesting its important role involved in the gender differences of AKI pathogenesis. We then found that knockdown of androgen receptor (AR) attenuated tubular damage, mitochondrial dysfunction and retarded the loss of renal function. Overexpression of Sirtuin 6 also showed similar results. Furthermore, in cultured tubular cells, dihydrotestosterone (DHT) decreased Sirtuin 6 expression and exacerbated cell apoptosis. Ectopic expression of Sirtuin 6 sufficiently inhibited DHT-induced cell apoptosis. Mechanically, we found AR inhibited Sirtuin 6, leading to the repression of binding of Sirtuin 6 with PGC-1α. This resulted in acetylation of PGC-1α and inhibition of its activity, further triggered the loss of mitochondrial homeostasis. Our results provided new insights to the underlying mechanisms of gender differences in AKI, suggesting Sirtuin 6 maybe a new therapeutic target for preventing AKI in male patients.

Human circulating small non-coding RNA signature as a non-invasive biomarker in clinical diagnosis of acute myeloid leukaemia.

Background: Acute myeloid leukaemia (AML) is the most common acute leukaemia in adults; AML is highly heterogeneous and involves abnormalities at multiple omics levels. Small non-coding RNAs (sncRNAs) present in body fluids are important regulatory molecules and considered promising non-invasive clinical diagnostic biomarkers for disease. However, the signature of sncRNA profile alteration in AML patient serum and bone marrow supernatant is still under exploration. Methods: We examined data for blood and bone marrow samples from 80 consecutive, newly-diagnosed patients with AML and 12 healthy controls for high throughput small RNA-sequencing. Differentially expressed sncRNAs were analysed to reveal distinct patterns between AML patients and controls. Machine learning methods were used to evaluate the efficiency of specific sncRNAs in discriminating individuals with AML from controls. The altered expression level of individual sncRNAs was evaluated by RT-PCR, Q-PCR, and northern blot. Correlation analysis was employed to assess sncRNA patterns between serum and bone marrow supernatant. Results: We identified over 20 types of sncRNA categories beyond miRNAs in both serum and bone marrow supernatant, with highly coordinated expression patterns between them. Non-classical sncRNAs, including rsRNA (62.86%), ysRNA (14.97%), and tsRNA (4.22%), dominated among serum sncRNAs and showed sensitive alteration patterns in AML patients. According to machine learning-based algorithms, the tsRNA-based signature robustly discriminated subjects with AML from controls and was more reliable than that comprising miRNAs. Our data also showed that serum tsRNAs to be closely associated with AML prognosis, suggesting the potential application of serum tsRNAs as biomarkers to assist in AML diagnosis. Conclusions: We comprehensively characterized the expression pattern of circulating sncRNAs in blood and bone marrow and their alteration signature between healthy controls and AML patients. This study enriches research of sncRNAs in the regulation of AML, and provides insights into the role of sncRNAs in AML.

Hypoxia induces alterations in tRNA modifications involved in translational control.

BACKGROUND: Adaptation to high-altitude hypobaric hypoxia has been shown to require a set of physiological traits enabled by an associated set of genetic modifications, as well as transcriptome regulation. These lead to both lifetime adaptation of individuals to hypoxia at high altitudes and generational evolution of populations as seen for instance in those of Tibet. Additionally, RNA modifications, which are sensitive to environmental exposure, have been shown to play pivotal biological roles in maintaining the physiological functions of organs. However, the dynamic RNA modification landscape and related molecular mechanisms in mouse tissues under hypobaric hypoxia exposure remain to be fully understood. Here, we explore the tissue-specific distribution pattern of multiple RNA modifications across mouse tissues. RESULTS: By applying an LC-MS/MS-dependent RNA modification detection platform, we identified the distribution of multiple RNA modifications in total RNA, tRNA-enriched fragments, and 17-50-nt sncRNAs across mouse tissues; these patterns were associated with the expression levels of RNA modification modifiers in different tissues. Moreover, the tissue-specific abundance of RNA modifications was sensitively altered across different RNA groups in a simulated high-altitude (over 5500 m) hypobaric hypoxia mouse model with the activation of the hypoxia response in mouse peripheral blood and multiple tissues. RNase digestion experiments revealed that the alteration of RNA modification abundance under hypoxia exposure impacted the molecular stability of tissue total tRNA-enriched fragments and isolated individual tRNAs, such as tRNAAla, tRNAval, tRNAGlu, and tRNALeu. In vitro transfection experiments showed that the transfection of testis total tRNA-enriched fragments from the hypoxia group into GC-2spd cells attenuated the cell proliferation rate and led to a reduction in overall nascent protein synthesis in cells. CONCLUSIONS: Our results reveal that the abundance of RNA modifications for different classes of RNAs under physiological conditions is tissue-specific and responds to hypobaric hypoxia exposure in a tissue-specific manner. Mechanistically, the dysregulation of tRNA modifications under hypobaric hypoxia attenuated the cell proliferation rate, facilitated the sensitivity of tRNA to RNases, and led to a reduction in overall nascent protein synthesis, suggesting an active role of tRNA epitranscriptome alteration in the adaptive response to environmental hypoxia exposure.

The Role of a Soybean 14-3-3 Gene (Glyma05g29080) on White Mold Resistance and Nodulation Investigations Using CRISPR-Cas9 Editing and RNA Silencing.

The role of a soybean 14-3-3 gene (Glyma05g29080) in defense against white mold and in nodulation was investigated by loss-of-gene-function with CRISPR-Cas9 editing and silencing of RNA interference (RNAi). Particle bombardment was used to introduce the CRISPR expression cassette to target the soybean 14-3-3 gene and an RNAi construct to silence gene transcription. Transmission of the edited 14-3-3 gene and the RNAi construct was confirmed in their respective progeny. The recovered transgenic plants and their progeny were significantly more susceptible to Sclerotinia sclerotiorum infection and showed a significant reduction in nodulation, thus confirming the role of the 14-3-3 gene (Glyma05g29080) in both nodulation and defense.

A D-Shaped Polymer Optical Fiber Surface Plasmon Resonance Biosensor for Breast Cancer Detection Applications.

Fiber-optic biosensors have garnered significant attention and witnessed rapid development in recent years owing to their remarkable attributes such as high sensitivity, immunity to electromagnetic interference, and real-time monitoring. They have emerged as a potential tool in the realm of biomarker detection for low-concentration and small molecules. In this paper, a portable and cost-effective optical fiber biosensor based on surface plasmon resonance for the early detection of breast cancer is demonstrated. By utilizing the aptamer human epidermal growth factor receptor 2 (HER2) as a specific biomarker for breast cancer, the presence of the HER2 protein can be detected through an antigen-antibody binding technique. The detection method was accomplished by modifying a layer of HER2 aptamer on the flat surface of a gold-coated D-shaped polymer optical fiber (core/cladding diameter 120/490 µm), of which the residual thickness after side-polishing was about 245 µm, the thickness of the coated gold layer was 50 nm, and the initial wavelength in pure water was around 1200 nm. For low-concentration detection of the HER2 protein, the device exhibited a wavelength shift of ~1.37 nm with a concentration of 1 µg/mL (e.g., 5.5 nM), which corresponded to a limit of detection of ~5.28 nM. Notably, the response time of the biosensor was measured to be as fast as 5 s. The proposed biosensor exhibits the potential for early detection of HER2 protein in initial cancer serum and offers a pathway to early prevention of breast cancer.

Corrigendum: Morphological characterization and transcriptome analysis of leaf angle mutant bhlh112 in maize [Zea mays L.].

[This corrects the article DOI: 10.3389/fpls.2022.995815.].

Morphological characterization and transcriptome analysis of leaf angle mutant bhlh112 in maize [Zea mays L.].

Leaf angle is an important agronomic trait in maize [Zea mays L.]. The compact plant phenotype, with a smaller leaf angle, is suited for high-density planting and thus for increasing crop yields. Here, we studied the ethyl methane sulfonate (EMS)-induced mutant bhlh112. Leaf angle and plant height were significantly decreased in bhlh112 compared to the wild-type plants. After treatment of seedlings with exogenous IAA and ABA respectively, under the optimal concentration of exogenous hormones, the variation of leaf angle of the mutant was more obvious than that of the wild-type, which indicated that the mutant was more sensitive to exogenous hormones. Transcriptome analysis showed that the ZmbHLH112 gene was related to the biosynthesis of auxin and brassinosteroids, and involved in the activation of genes related to the auxin and brassinosteroid signal pathways as well as cell elongation. Among the GO enrichment terms, we found many differentially expressed genes (DEGs) enriched in the cell membrane and ribosomal biosynthesis, hormone biosynthesis and signaling pathways, and flavonoid biosynthesis, which could influence cell growth and the level of endogenous hormones affecting leaf angle. Therefore, ZmbHLH112 might regulate leaf angle development through the auxin signaling and the brassinosteroid biosynthesis pathways. 12 genes related to the development of leaf were screened by WGCNA; In GO enrichment and KEGG pathways, the genes were mainly enriched in rRNA binding, ribosome biogenesis, Structural constituent of ribosome; Arabidopsis ribosome RNA methyltransferase CMAL is involved in plant development, likely by modulating auxin derived signaling pathways; The free 60s ribosomes and polysomes in the functional defective mutant rice minute-like1 (rml1) were significantly reduced, resulting in plant phenotypic diminution, narrow leaves, and growth retardation; Hence, ribosomal subunits may play an important role in leaf development. These results provide a foundation for further elucidation of the molecular mechanism of the regulation of leaf angle in maize.

A new LKB1 activator, piericidin analogue S14, retards renal fibrosis through promoting autophagy and mitochondrial homeostasis in renal tubular epithelial cells.

Background: Liver kinase B1 (LKB1) is the key regulator of energy metabolism and cell homeostasis. LKB1 dysfunction plays a key role in renal fibrosis. However, LKB1 activators are scarce in commercial nowadays. This study aims to discover a new drug molecule, piericidin analogue S14 (PA-S14), preventing renal fibrosis as a novel activator to LKB1. Methods: Our group isolated PA-S14 from the broth culture of a marine-derived Streptomyces strain and identified its binding site. We adopted various CKD models or AKI-CKD model (5/6 nephrectomy, UUO, UIRI and adriamycin nephropathy models). TGF-ß-stimulated renal tubular cell culture was also tested. Results: We identified that PA-S14 binds with residue D176 in the kinase domain of LKB1, and then induces the activation of LKB1 through its phosphorylation and complex formation with MO25 and STRAD. As a result, PA-S14 promotes AMPK activation, triggers autophagosome maturation, and increases autophagic flux. PA-S14 inhibited tubular cell senescence and retarded fibrogenesis through activation of LKB1/AMPK signaling. Transcriptomics sequencing and mutation analysis further demonstrated our results. Conclusion: PA-S14 is a novel leading compound of LKB1 activator. PA-S14 is a therapeutic potential to renal fibrosis through LKB1/AMPK-mediated autophagy and mitochondrial homeostasis pathways.

Screening of the Key Genes and Signalling Pathways for Diabetic Nephropathy Using Bioinformatics Analysis.

Background: This study aimed to identify biological markers for diabetic nephropathy (DN) and explore their underlying mechanisms. Methods: Four datasets, GSE30528, GSE47183, GSE104948, and GSE96804, were downloaded from the Gene Expression Omnibus (GEO) database. The differentially expressed genes (DEGs) were identified using the "limma" package, and the "RobustRankAggreg" package was used to screen the overlapping DEGs. The hub genes were identified using cytoHubba of Cytoscape. Logistic regression analysis was used to further analyse the hub genes, followed by receiver operating characteristic (ROC) curve analysis to predict the diagnostic effectiveness of the hub genes. Correlation analysis and enrichment analysis of the hub genes were performed to identify the potential functions of the hub genes involved in DN. Results: In total, 55 DEGs, including 38 upregulated and 17 downregulated genes, were identified from the three datasets. Four hub genes (FN1, CD44, C1QB, and C1QA) were screened out by the "UpSetR" package, and FN1 was identified as a key gene for DN by logistic regression analysis. Correlation analysis and enrichment analysis showed that FN1 was positively correlated with four genes (COL6A3, COL1A2, THBS2, and CD44) and with the development of DN through the extracellular matrix (ECM)-receptor interaction pathway. Conclusions: We identified four candidate genes: FN1, C1QA, C1QB, and CD44. On further investigating the biological functions of FN1, we showed that FN1 was positively correlated with THBS2, COL1A2, COL6A3, and CD44 and involved in the development of DN through the ECM-receptor interaction pathway. THBS2, COL1A2, COL6A3, and CD44 may be novel biomarkers and target therapeutic candidates for DN.