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Toxins Jun 2024Cytotoxins (CTs) are three-finger membrane-active toxins present mainly in cobra venom. Our analysis of the available CT amino acid sequences, literature data on their... (Review)
Review
Cytotoxins (CTs) are three-finger membrane-active toxins present mainly in cobra venom. Our analysis of the available CT amino acid sequences, literature data on their membrane activity, and conformational equilibria in aqueous solution and detergent micelles allowed us to identify specific amino acid residues which interfere with CT incorporation into membranes. They include Pro9, Ser28, and Asn/Asp45 within the N-terminal, central, and C-terminal loops, respectively. There is a hierarchy in the effect of these residues on membrane activity: Pro9 > Ser28 > Asn/Asp45. Taking into account all the possible combinations of special residues, we propose to divide CTs into eight groups. Group 1 includes toxins containing all of the above residues. Their representatives demonstrated the lowest membrane activity. Group 8 combines CTs that lack these residues. For the toxins from this group, the greatest membrane activity was observed. We predict that when solely membrane activity determines the cytotoxic effects, the activity of CTs from a group with a higher number should exceed that of CTs from a group with a lower number. This classification is supported by the available data on the cytotoxicity and membranotropic properties of CTs. We hypothesize that the special amino acid residues within the loops of the CT molecule may indicate their involvement in the interaction with non-lipid targets.
Topics: Cell Membrane; Animals; Cytotoxins; Elapid Venoms; Amino Acids; Amino Acid Sequence; Humans
PubMed: 38922156
DOI: 10.3390/toxins16060262 -
JGH Open : An Open Access Journal of... Jun 2024After pancreaticoduodenectomy, 20-40% of patients develop steatotic liver disease (SLD), and steatohepatitis can be a problem. Although patatin-like phospholipase...
AIM
After pancreaticoduodenectomy, 20-40% of patients develop steatotic liver disease (SLD), and steatohepatitis can be a problem. Although patatin-like phospholipase domain-containing 3 protein (PNPLA3) and transmembrane 6 superfamily member 2 (TM6SF2) polymorphisms are involved in SLD and steatohepatitis development, whether this is the case after pancreaticoduodenectomy is unclear.
METHODS AND RESULTS
Forty-three patients with pancreatic cancer who underwent pancreaticoduodenectomy at our hospital between April 1, 2018, and March 31, 2021, were included. We extracted DNA from noncancerous areas of residual specimens after pancreaticoduodenectomy and determined PNPLA3 and TM6SF2 gene polymorphisms using real-time polymerase chain reaction. SLD was defined as a liver with an attenuation value of ≤40 HU or a liver-to-spleen ratio of ≤0.9 on computed tomography. We defined high hepatic fibrosis indexes (HFI) instead of steatohepatitis as a Fibrosis-4 index of ≥2.67 or nonalcoholic fatty liver disease fibrosis score of ≥0.675 in patients with SLD. The cumulative incidence of SLD ( = 0.299) and high HFI ( = 0.987) after pancreaticoduodenectomy were not significantly different between the PNPLA3 homozygous and minor allele groups. The incidences of high HFI at 1 year after pancreaticoduodenectomy were 16.8% and 27.0% in the TM6SF2 major homozygous and minor allele groups, respectively, with a significant difference in the cumulative incidence ( = 0.046).
CONCLUSION
The TM6SF2 minor allele may contribute to steatohepatitis development after pancreaticoduodenectomy.
PubMed: 38919271
DOI: 10.1002/jgh3.13113 -
Bioresources and Bioprocessing Jun 2024Phospholipase A1 (PLA1) is a kind of specific phospholipid hydrolase widely used in food, medical, textile. However, limitations in its expression and enzymatic activity...
Phospholipase A1 (PLA1) is a kind of specific phospholipid hydrolase widely used in food, medical, textile. However, limitations in its expression and enzymatic activity have prompted the investigation of the phospholipase-assisting protein PlaS. In this study, we elucidate the role of PlaS in enhancing the expression and activity of PlaA1 through N-terminal truncation. Our research demonstrates that truncating the N-terminal region of PlaS effectively overcomes its inhibitory effect on host cells, resulting in improved cell growth and increased protein solubility of the protein. The yeast two-hybrid assay confirms the interaction between PlaA1 and N-terminal truncated PlaS (∆N27 PlaS), highlighting their binding capabilities. Furthermore, in vitro studies using Biacore analysis reveal a concentration-dependent and specific binding between PlaA1 and ∆N27 PlaS, exhibiting high affinity. Molecular docking analysis provides insights into the hydrogen bond interactions between ∆N27 PlaS and PlaA1, identifying key amino acid residues crucial for their binding. Finally, the enzyme activity of PLA1 was boost to 8.4 U/mL by orthogonal test. Study significantly contributes to the understanding of the interaction mechanism between PlaS and PlaA1, offering potential strategies for enhancing PlaA1 activity through protein engineering approaches.
PubMed: 38916814
DOI: 10.1186/s40643-024-00777-1 -
Clinical Kidney Journal Jun 2024Membranous nephropathy (MN) management poses challenges, particularly in selecting appropriate immunosuppressive treatments (IST) and monitoring disease progression and... (Review)
Review
Membranous nephropathy (MN) management poses challenges, particularly in selecting appropriate immunosuppressive treatments (IST) and monitoring disease progression and complications. This article highlights 10 key tips for the management of primary MN based on current evidence and clinical experience. First, we advise against prescribing IST to patients without nephrotic syndrome (NS), emphasizing the need for close monitoring of disease progression. Second, we recommend initiating IST in patients with persistent NS or declining kidney function. Third, we suggest prescribing rituximab (RTX) or RTX combined with calcineurin inhibitors in medium-risk patients. Fourth, we propose cyclophosphamide-based immunosuppression for high-risk patients. Fifth, we discourage the use of glucocorticoid monotherapy or mycophenolate mofetil as initial treatments. Sixth, we underscore the importance of preventing infectious complications in patients receiving IST. Seventh, we emphasize the need for personalized monitoring of IST by closely measuring kidney function, proteinuria, serum albumin and anti-M-type phospholipase A2 receptor levels. Eighth, we recommend a stepwise approach in the treatment of resistant disease. Ninth, we advise adjusting treatment for relapses based on individual risk profiles. Finally, we caution about the potential recurrence of MN after kidney transplantation and suggest appropriate monitoring and treatment strategies for post-transplantation MN. These tips provide comprehensive guidance for clinicians managing MN, aiming to optimize patient outcomes and minimize complications.
PubMed: 38915435
DOI: 10.1093/ckj/sfae129 -
Frontiers in Immunology 2024This study aimed to demonstrate the potential of activated leukocyte cell adhesion molecule (ALCAM), hemopexin (HPX), and peroxiredoxin 6 (PRDX6) as urine biomarkers for...
Longitudinal assessment of urinary ALCAM, HPX, and PRDX6 in Korean patients with systemic lupus erythematosus: implications for disease activity monitoring and treatment response.
INTRODUCTION
This study aimed to demonstrate the potential of activated leukocyte cell adhesion molecule (ALCAM), hemopexin (HPX), and peroxiredoxin 6 (PRDX6) as urine biomarkers for systemic lupus erythematosus (SLE).
METHODS
Urine samples were collected from 138 Korean patients with SLE from the Ajou Lupus Cohort and 39 healthy controls (HC). The concentrations of urine biomarkers were analyzed using enzyme-linked immunosorbent assay kits specific for ALCAM, HPX, and PRDX6, respectively. Receiver operating characteristic (ROC) curve analysis was performed to evaluate the diagnostic utility, and Pearson's correlation analysis was conducted to assess the relationships between the disease activity and urine biomarkers.
RESULTS
Patients with SLE and patients with lupus nephritis (LN) showed significantly elevated ALCAM, HPX, and PRDX6 levels compared with HCs. ALCAM, HPX, and PRDX6 showed significant diagnostic values, especially for lupus nephritis (LN), with areas under the receiver operating characteristic curve for LN was 0.850 for ALCAM (95% CI, 0.778-0.921), 0.781 for HPX (95% CI, 0.695-0.867), and 0.714 for PRDX6 (95% CI, 0.617-0.812). Correlation analysis revealed that all proteins were significantly associated with anti-double stranded DNA antibody (ALCAM, r = 0.350, p < 0.001; HPX, r = 0.346, p < 0.001; PRDX6, r = 0.191, p = 0.026) and SLEDAI (ALCAM, r = 0.526, p < 0.001; HPX, r = 0.479, p < 0.001; PRDX6, r = 0.262, p = 0.002). Results from the follow-up of the three biomarker levels in these patients revealed a significant decrease, showing a positive correlation with changes in SLEDAI-2k scores (ALCAM, r = 0.502, p < 0.001; HPX, r = 0.475, p < 0.001; PRDX6, r = 0.245, p = 0.026), indicating their potential as indicators for tracking disease activity.
DISCUSSIONS
Urinary ALCAM, HPX, and PRDX6 levels have diagnostic value and reflect disease activity in Korean patients with SLE, emphasizing their potential for non-invasive monitoring and treatment response evaluation.
Topics: Humans; Female; Male; Biomarkers; Adult; Lupus Erythematosus, Systemic; Republic of Korea; Peroxiredoxin VI; Middle Aged; Fetal Proteins; Longitudinal Studies; Severity of Illness Index; Young Adult; Antigens, CD; ROC Curve; Cell Adhesion Molecules, Neuronal; Case-Control Studies; Lupus Nephritis; Activated-Leukocyte Cell Adhesion Molecule
PubMed: 38915417
DOI: 10.3389/fimmu.2024.1369385 -
Biomedicine & Pharmacotherapy =... Jun 2024Snakebite envenomation often induces acute kidney injury (AKI) and acute liver injury (ALI), leading to augmented injuries and poor rehabilitation. Phospholipase A (PLA)...
Snakebite envenomation often induces acute kidney injury (AKI) and acute liver injury (ALI), leading to augmented injuries and poor rehabilitation. Phospholipase A (PLA) and metalloproteinase (SVMP) present in venom are responsible for the envenomation-associated events. In this study, mice envenomed with Deinagkistrodon acutus, Naja atra, or Agkistrodon halys pallas venom exhibited typical AKI and ALI symptoms, including significantly increased plasma levels of myoglobin, free hemoglobin, uric acid, aspartate aminotransferase, and alanine aminotransferase and upregulated expression of kidney NGAL and KIM-1. These effects were significantly inhibited when the mice were pretreated with natural inhibitors of PLA and SVMP isolated from Sinonatrix annularis (SaPLIγ and SaMPI). The inhibitors protected the physiological structural integrity of the renal tubules and glomeruli, alleviating inflammatory infiltration and diffuse hemorrhage in the liver. Furthermore, the dual therapy alleviated oxidative stress and apoptosis in the kidneys and liver by mitigating mitochondrial damage, thereby effectively reducing the lethal effect of snake venom in the inhibitor-treated mouse model. This study showed that dual therapy with inhibitors of metalloproteinase and phospholipase can effectively prevent ALI and AKI caused by snake bites. Our findings suggest that intrinsic inhibitors present in snakes are prospective therapeutic agents for multi-organ injuries caused by snake envenoming.
PubMed: 38908206
DOI: 10.1016/j.biopha.2024.116967 -
BMC Nephrology Jun 2024The concomitant occurrence of membranous nephropathy and anti-glomerular basement (anti-GBM) disease has been previously described but is extremely rare. However,...
BACKGROUND
The concomitant occurrence of membranous nephropathy and anti-glomerular basement (anti-GBM) disease has been previously described but is extremely rare. However, delayed recognition or misdiagnosis leads to delayed treatment, resulting in worse renal and patient outcomes.
CASE PRESENTATION
We present 3 patients with rapidly progressive glomerulonephritis (RPGN), anti-GBM and serum-positive M-type phospholipase A2 receptor (anti-PLA2R) antibody. Renal biopsies revealed PLA2R-associated membranous nephropathy with anti-GBM glomerulonephritis. We analyzed the clinical and pathological characteristics and discussed that the correct diagnosis of membranous nephropathy with anti-GBM should rely on a combination of renal biopsy findings and serological testing. Despite aggressive treatment, one patient received maintenance hemodialysis, one patient progressed to CKD 3 stage, and the other patient died of cerebral infarction.
CONCLUSION
The simultaneous occurrence of membranous nephropathy and anti-GBM disease is extremely rare. The correct diagnosis of membranous nephropathy with anti-GBM relies on a combination of renal biopsy findings and serological testing. Early diagnosis is needed to improve the renal dysfunction.
Topics: Humans; Glomerulonephritis, Membranous; Male; Female; Middle Aged; Anti-Glomerular Basement Membrane Disease; Receptors, Phospholipase A2; Adult; Autoantibodies; Biopsy; Glomerulonephritis
PubMed: 38907217
DOI: 10.1186/s12882-024-03637-4 -
Discover Oncology Jun 2024Clear cell renal cell carcinoma (ccRCC) is the most prevalent subtype of renal tumors and is associated with a unfavorable prognosis. Disulfidptosis is a recently...
BACKGROUND
Clear cell renal cell carcinoma (ccRCC) is the most prevalent subtype of renal tumors and is associated with a unfavorable prognosis. Disulfidptosis is a recently identified form of cell death mediated by disulfide bonds. Numerous studies have highlighted the significance of immune checkpoint genes (ICGs) in ccRCC. Nevertheless, the involvement of disulfidptosis-related immune checkpoint genes (DRICGs) in ccRCC remains poorly understood.
METHODS
The mRNA expression profiles and clinicopathological data of ccRCC patients were obtained from The Cancer Genome Atlas and Gene Expression Omnibus (GEO) databases. The associations between disulfidptosis-related genes (DRGs) and immune checkpoint genes (ICGs) were assessed to identify DRICGs. Cox regression analysis and least absolute shrinkage and selection operator (LASSO) analysis were conducted to construct a risk signature.
RESULTS
A total of 39 differentially expressed immune-related candidate genes were identified. A prognostic signature was constructed utilizing nine DRICGs (CD276, CD80, CD86, HLA-E, LAG3, PDCD1LG2, PVR, TIGIT, and TNFRSF4) and validated using GEO data. The risk model functioned as an independent prognostic indicator for ccRCC, while the associated nomogram provided a reliable scoring system for ccRCC. Gene set enrichment analysis indicated enrichment of phospholipase D, antigen processing and presentation, and ascorbate and aldarate metabolism-related signaling pathways in the high-risk group. Furthermore, the DRICGs exhibited correlations with the infiltration of various immune cells. It is noteworthy that patients with ccRCC categorized into distinct risk groups based on this model displayed varying sensitivities to potential therapeutic agents.
CONCLUSIONS
The novel DRICG-based risk signature is a reliable indicator for the prognosis of ccRCC patients. Moreover, it also aids in drug selection and correlates with the tumour immune microenvironment in ccRCC.
PubMed: 38904744
DOI: 10.1007/s12672-024-01105-x -
The Journal of Biological Chemistry Jun 2024Phospholipase A2 receptor 1 (PLA2R1) is a 180-kDa transmembrane protein that plays a role in inflammation and cancer, and is the major autoantigen in membranous...
Phospholipase A2 receptor 1 (PLA2R1) is a 180-kDa transmembrane protein that plays a role in inflammation and cancer, and is the major autoantigen in membranous nephropathy (MN), a rare but severe autoimmune kidney disease. A soluble form of PLA2R1 has been detected in mouse and human serum. It is likely produced by proteolytic shedding of membrane-bound PLA2R1 but the mechanism is unknown. Here, we show that human PLA2R1 is cleaved by A Disintegrin And Metalloprotease 10 (ADAM10) and ADAM17 in HEK293 cells, mouse embryonic fibroblasts and human podocytes. By combining site-directed mutagenesis and sequencing, we determined the exact cleavage site within the extracellular juxtamembrane stalk of human PLA2R1. Orthologs and paralogs of PLA2R1 are also shed. By using pharmacological inhibitors and genetic approaches with RNA interference and knock-out cellular models, we identified a major role of ADAM10 in the constitutive shedding of PLA2R1, and a dual role of ADAM10 and ADAM17 in the stimulated shedding. We did not observe evidence for cleavage by β- or γ-secretase, suggesting that PLA2R1 may not be a substrate for Regulated Intramembrane Proteolysis. PLA2R1 shedding occurs constitutively and can be triggered by the calcium ionophore ionomycin, the protein kinase C inducer PMA, cytokines and lipopolysaccharides, in vitro and in vivo. Altogether, our results show that PLA2R1 is a novel substrate for ADAM10 and ADAM17, producing a soluble form that is increased in inflammatory conditions and likely exerts various functions in physiological and pathophysiological conditions including inflammation, cancer and MN.
PubMed: 38897568
DOI: 10.1016/j.jbc.2024.107480 -
BioRxiv : the Preprint Server For... Jun 2024Lysosomes catabolize lipids and other biological molecules, a function essential for cellular and organismal homeostasis. Key to lipid catabolism in the lysosome is...
Lysosomes catabolize lipids and other biological molecules, a function essential for cellular and organismal homeostasis. Key to lipid catabolism in the lysosome is bis(monoacylglycero)phosphate (BMP), a major lipid constituent of intralysosomal vesicles (ILVs) and a stimulator of lipid-degrading enzymes. BMP levels are altered in a broad spectrum of human conditions, including neurodegenerative diseases. Although BMP synthase was recently discovered, it has long been thought that BMP's unique stereochemistry confers resistance to acid phospholipases, a requirement for its role in the lysosome. Here, we demonstrate that PLA2G15, a major lysosomal phospholipase, efficiently hydrolyzes BMP with primary esters regardless of stereochemistry. Interestingly, we discover that BMP's unique esterification position is what confers resistance to hydrolysis. Purified PLA2G15 catabolizes most BMP species derived from cell and tissue lysosomes under acidic conditions. Furthermore, PLA2G15 catalytic activity against synthesized BMP stereoisomers with primary esters was comparable to its canonical substrates. Conversely, BMP with secondary esters is intrinsically stable in vitro and requires acyl migration for hydrolysis in lysosomes. Consistent with our biochemical data, PLA2G15-deficient tissues and cells accumulate multiple BMP species, a phenotype reversible by supplementing wildtype PLA2G15 but not its catalytically dead mutant. Increasing BMP levels by targeting PLA2G15 reverses the cholesterol accumulation phenotype in Niemann Pick Disease Type C (NPC1) patient fibroblasts and significantly ameliorate disease pathologies in NPC1-deficient mice leading to extended lifespan. Our findings establish the rules that govern the stability of BMP in the lysosome and identify PLA2G15 as a lysosomal BMP hydrolase and as a potential target for modulating BMP levels for therapeutic intervention.
PubMed: 38895439
DOI: 10.1101/2024.06.07.597919