bims-supasi 2025-06-15 papers

bims-supasi

Biomed News

on Sulfation pathways and signalling

Issue of 2025–06–15
fifteen papers selected by
Jonathan Wolf Mueller, University of Birmingham

Rapid Synthesis of Oversulfated Chondroitin Sulfate.
Metal-mediated IL-8 binding to heparan sulfate evaluated by electrochemical impedance spectroscopy.
Bruch's membrane heparan sulfate retains lipoproteins in the early stages of age-related macular degeneration.
A highly sulfated α-1,4-linked Galactoglucan of Antrodia cinnamomea with anti-inflammatory and anti-Cancer activities.
Endothelial lipase facilitates low-density lipoprotein (LDL) uptake in LDL receptor deficiency by a heparan sulfate proteoglycan-dependent mechanism.
Association of sex hormone-binding globulin and dyslipidemia with Japanese postmenopausal women: a cross-sectional study.
Glycosaminoglycan-driven lipoprotein uptake protects tumours from ferroptosis.
Upregulation of Sulfated N-Glycans in Serum as Predictive Biomarkers for Early-Stage Breast Cancer.
Uremic toxins levels are associated with miR-223 in chronic kidney disease-associated anemia.
Effect of Gracilaria fisheri sulfated galactan with increased sulfation on cell migration and expression of cell adhesion molecules in sodium oxalate-induced HK-2 cell injury.
Analysis of chondroitin degradation by components of a Bacteroides caccae polysaccharide utilization locus.
Characterization of an Endo-1,3-fucanase from Glycoside Hydrolase Family 187 Within a Polysaccharide Utilization Locus of Wenyingzhuangia aestuarii OF219.
Shenfushu granules attenuate diabetic kidney disease by inhibiting PIK3R1/protein kinase B/heparanase-mediated endothelial-mesenchymal transition.
Indoxyl sulfate as a potential tubular function marker across kidney disease models.
Transmembrane Protein-184A Interacts with Syndecan-4 and Rab GTPases and Is Required to Maintain VE-Cadherin Levels.

Biol Pharm Bull. 2025 ;48(6): 801-804

Rapid Synthesis of Oversulfated Chondroitin Sulfate.

Hiroshi Akiyama, Hiori Misu, Yume Tsuruyama, Sanami Isaka, Utano Makiyama, Mayumi Ikegami-Kawai, Natsuko Miki, Yukari Nakagawa, Hideki Tamura, Yusuke Iwasaki, Rie Ito.

  Oversulfated chondroitin sulfate (OSCS) is a chondroitin sulfate ester in which all hydroxyl groups have been converted to sulfuric acid esters. Here, we describe a rapid, novel synthesis method for OSCS. 1H-NMR analysis revealed that all signals derived from the protons of N-acetyl-galactosamine and glucuronic acid in the synthesized OSCS were shifted downfield due to sulfonation compared with the chondroitin sulfate (CS) starting material. Comparison of the edited heteronuclear single quantum correlation spectrum of the prepared OSCS with that of the Japanese Pharmacopoeia OSCS reference standard showed excellent agreement between the main correlation peaks. The proposed novel synthesis method for OSCS is faster and simpler than the conventional method.

Keywords:  NMR; edited heteronuclear single quantum correlation; oversulfated chondroitin sulfate; synthesis

DOI:  https://doi.org/10.1248/bpb.b25-00117
Chemistry. 2025 Jun 08. e202501011

Metal-mediated IL-8 binding to heparan sulfate evaluated by electrochemical impedance spectroscopy.

Ariel Shitrit, Israel Alshanski, Karin Mor, Jörg Rademann, Raghavendra Kikkeri, Mattan Hurevich, Shlomo Yitzchaik.

  Heparan sulfate (HS) interactions with interleukin 8 (IL-8) are crucial for immune system response. The structural features of the HS and the environmental entities, such as metal ions, can regulate these interactions. However, it is challenging to evaluate the effect of each parameter on the interactions because of low accessibility to well-defined saccharides and the lack of characteristic features to be determined by analytical tools. We evaluated the effect of the HS structural features on IL-8 binding affinity utilizing electrochemical impedance spectroscopy (EIS) and X-ray photoelectron spectroscopy. We showed that the metal Ions Ca2+ and Mg2+ dissimilarly mediate the interactions of HS and IL-8 in structure structure-dependent manner of the HS. We showed that in all glycans, a positive synergistic effect on IL-8 binding was observed. For several glycans, the presence of ions resulted in a dramatic increase in the affinity to IL-8, while for other glycans, a milder effect was observed. This demonstrated that both structural motifs and environmental features are crucial for maintaining the interactions between the HS and IL-8.

Keywords:  EIS; Heparan sulfate; Interleukin 8; Metal Ions; XPS

DOI:  https://doi.org/10.1002/chem.202501011
Proc Natl Acad Sci U S A. 2025 Jun 17. 122(24): e2500727122

Bruch's membrane heparan sulfate retains lipoproteins in the early stages of age-related macular degeneration.

Christopher B Toomey, Savanna Pflugmacher, Kamalu Park, Jessica Pihl, Sammy Weiser Novak, Jessica Rodriguez, Maryam Jalali, Jaesoo Jung, Madeline Mozafari, Sima P Omran, Cameron K Pormir, Jill Hauer, Chelsea Painter, Evan Walker, Alex S Huang, Daniela Boassa, James T Handa, Teodor Aastrup, Philip L S M Gordts, Jeffrey D Esko.

  Lipoprotein retention in Bruch's membrane is a key event in the pathobiology of early and intermediate age-related macular degeneration (AMD). However, the mechanism of lipoprotein retention in BrM is unknown. Given the established role of glycosaminoglycans (GAG) in binding lipoproteins, our laboratory sought to determine the role of GAGs in AMD BrM. In this study, BrM GAG content in AMD pathobiology was analyzed in human postmortem tissue. Strikingly, increased levels of highly sulfated heparan sulfate were present in AMD Bruch's membrane as compared to non-AMD samples. In addition, using scanning electron microscopy of postmortem AMD tissue, we show aggregates of lipoprotein-like particles on the retinal pigmented epithelium side of Bruch's membrane adjacent to heparan sulfate. We also show that heparin displaces lipoproteins rich in apolipoprotein A1 from human BrM, suggesting their identity as high-density lipoproteins. Using human BrM immobilized to quartz crystal microbalance biosensor (QCM) chips, we show that heparan sulfate is required for lipoprotein binding to BrM and soluble heparan sulfate can remove lipoproteins bound to BrM. Thus, our data establish that heparan sulfate regulates lipoprotein deposition in AMD BrM. These findings provide a foundation for targeted therapies capable of either preventing lipoprotein accumulation or removing drusen in the early and intermediate stages of AMD prior to vision loss.

Keywords:  Bruch’s membrane; age-related macular degeneration; heparan sulfate; lipoproteins

DOI:  https://doi.org/10.1073/pnas.2500727122
Carbohydr Polym. 2025 Sep 15. pii: S0144-8617(25)00593-4. [Epub ahead of print]364 123810

A highly sulfated α-1,4-linked Galactoglucan of Antrodia cinnamomea with anti-inflammatory and anti-Cancer activities.

Ching-Yi Lu, Wei-Lun Qiu, Chi-Hsein Chao, Mei-Kuang Lu, Chia-Chuan Chang.

  Sulfate polysaccharides (SPS) are polysaccharides with highly anionic properties due to of the binding of negatively charged sulfate groups to the central sugar backbone. This study aims to structurally elucidate and functionally evaluate a natural SPS purified from fraction 2 of SPS of 50 mM ammonium sulfate feeding of A. cinnamomea, noted as N50 F2. N50 F2 exhibited a high sulfate content of 3.89 mmol/g demonstrated excellent anti-cancer activity. Its anti-inflammatory effect is mediated by down-regulating AKT phosphorylation and reducing TGFRII expression in LPS-induced macrophage cells. The anti-cancer activity of N50 F2 is achieved through the down-regulation of the phosphorylation of AKT/ERK/EGFR/FAK and the inhibition of slug, TGFRI, and TGFRII's expression. N50 F2 also activated apoptotic related molecules of CHOP, and cleavage PARP, caspase 3 in lung cancer cells. Structural delineation demonstrated that N50 F2 was a sulfated α-1,4-linked galactoglucan, with a glucosyl branch on the 3-O position of one skeleton moiety and a galactosyl on the 6-O position of another, with sulfate substitutions on all the hydroxy positions. This study offers a reliable production method for SPS and highlights the potential of SPS for pharmaceutical applications.

Keywords:  Anti-cancer; Antrodia cinnamomea; Galacto-glucan; Sulfated polysaccharide

DOI:  https://doi.org/10.1016/j.carbpol.2025.123810
bioRxiv. 2025 May 26. pii: 2025.03.02.640965. [Epub ahead of print]

Endothelial lipase facilitates low-density lipoprotein (LDL) uptake in LDL receptor deficiency by a heparan sulfate proteoglycan-dependent mechanism.

Olivia White, Zahra Aligabi, Kendall H Burks, Jingrong Tang, Nathan O Stitziel, Ira J Goldberg, Alan T Remaley, Diego Lucero.

Current lipid-lowering drugs are relatively ineffective in reducing low-density lipoprotein (LDL) cholesterol in patients with Familial Hypercholesterolemia (FH) due to a dysfunctional LDL receptor (LDLR). However, LDL cholesterol reductions have been achieved in FH patients using angiopoietin-like 3 (ANGPTL3) inhibitors, which act through an uncharacterized, LDLR-independent pathway that requires endothelial lipase (EL). Here, we aim to investigate EL's direct role in LDLR-independent uptake of LDL in hepatocytes. Control and LDLR-KO HepG2 cells were transfected with an empty plasmid or a plasmid encoding the human LIPG gene, and the cellular uptake of fluorescent human LDL was measured by FACS. To test the contribution of heparan sulfate proteoglycans (HSPG), LDL uptake was assessed with and without the pre-incubation with heparin or a heparinase cocktail. Finally, tetrahydrolipstatin was used to inhibit EL enzymatic activity in uptake studies. Unsurprisingly, LDLR-KO HepG2 cells showed an 80% reduction in LDL uptake compared to controls (p<0.001). Remarkably, EL overexpression almost fully rescued LDL uptake in LDLR-KO cells (p<0.001), without effects in control cells. EL-mediated LDL uptake was completely blocked by heparinases and heparin in LDLR-KO cells, suggesting a crucial role of HSPG in EL-mediated LDL uptake. Notably, treatment with tetrahydrolipstatin reduced LDL uptake in EL-overexpressing LDLR-KO cells (p=0.0015). Our data reveals that EL facilitates the uptake of LDL in hepatocytes through an LDLR-independent, HSPG-dependent pathway that involves EL's enzymatic activity. This pathway provides an additional mechanism to explain the reduction of LDL cholesterol induced by ANGPTL3 inhibitors and represents a potential druggable target to treat FH.

DOI: https://doi.org/10.1101/2025.03.02.640965
Lipids Health Dis. 2025 Jun 10. 24(1): 212

Association of sex hormone-binding globulin and dyslipidemia with Japanese postmenopausal women: a cross-sectional study.

Takahiro Ichikawa, Hiroshi Okada, Masahide Hamaguchi, Megumi Hara, Naoyuki Takashima, Sadao Suzuki, Shiroh Tanoue, Yasufumi Kato, Mako Nagayoshi, Takashi Tamura, Michiaki Fukui, Keitaro Matsuo.

   BACKGROUND: In postmenopausal women, lower levels of sex hormone-binding globulin (SHBG) have been linked to various metabolic conditions. The association between SHBG levels and the presence of dyslipidemia was investigated in comparison with other sex hormones.
METHODS: Data from 570 postmenopausal women were analyzed. To assess the relationship between circulating sex hormone concentrations and dyslipidemia, logistic regression and receiver operating characteristic (ROC) curve analyses were performed to assess the relationships.
RESULTS: Participants had a median age of 51.0 years (49.0-53.0). The multivariate analysis revealed that SHBG levels were significantly associated with dyslipidemia. Specifically, low SHBG levels correlated with hypertriglyceridemia and low high-density lipoprotein levels. The area under the curve (AUC) and the optimal SHBG level cutoff value for identifying the presence of dyslipidemia were 0.626 and 69.0 nmol/L, respectively. The AUCs for SHBG levels were highest for estradiol (E2), total testosterone (TT) and dehydroepiandrosterone sulfate (DHEAS) levels.
CONCLUSIONS: SHBG levels were significantly associated with dyslipidemia in postmenopausal women and outperformed E2, TT, and DHEAS levels. These findings highlight SHBG as a potential biomarker for dyslipidemia risk in postmenopausal women, warranting further research into its prognostic utility.

Keywords:  Cohort; Dyslipidemia; Japanese; Menopause; Sex hormone-binding globulin (SHBG)

DOI:  https://doi.org/10.1186/s12944-025-02634-2
Nature. 2025 Jun 11.

Glycosaminoglycan-driven lipoprotein uptake protects tumours from ferroptosis.

Dylan Calhoon, Lingjie Sang, Fubo Ji, Divya Bezwada, Sheng-Chieh Hsu, Feng Cai, Nathaniel Kim, Amrita Basu, Renfei Wu, Anastasia Pimentel, Bailey Brooks, Konnor La, Ana Paulina Serrano, Daniel L Cassidy, Ling Cai, Vanina Toffessi-Tcheuyap, Maryam E Moussa, Winnie Uritboonthai, Linh Truc Hoang, Meghana Kolli, Brooklyn Jackson, Vitaly Margulis, Gary Siuzdak, James Brugarolas, Ian Corbin, Derek A Pratt, Ryan J Weiss, Ralph J DeBerardinis, Kıvanç Birsoy, Javier Garcia-Bermudez.

Lipids are essential components of cancer cells due to their structural and signalling roles1. To meet metabolic demands, many cancers take up extracellular lipids2-5; however, how these lipids contribute to cancer growth and progression remains poorly understood. Here, using functional genetic screens, we identify uptake of lipoproteins-the primary mechanism for lipid transport in circulation-as a key determinant of ferroptosis sensitivity in cancer. Lipoprotein supplementation robustly inhibits ferroptosis across diverse cancer types, primarily through the delivery of α-tocopherol (α-toc), the most abundant form of vitamin E in human lipoproteins. Mechanistically, cancer cells take up lipoproteins through a pathway dependent on sulfated glycosaminoglycans (GAGs) linked to cell-surface proteoglycans. Disrupting GAG biosynthesis or acutely degrading surface GAGs reduces lipoprotein uptake, sensitizes cancer cells to ferroptosis and impairs tumour growth in mice. Notably, human clear cell renal cell carcinomas-a lipid-rich malignancy-exhibit elevated levels of chondroitin sulfate and increased lipoprotein-derived α-toc compared with normal kidney tissue. Together, our study establishes lipoprotein uptake as a critical anti-ferroptotic mechanism in cancer and implicates GAG biosynthesis as a therapeutic target.

DOI: https://doi.org/10.1038/s41586-025-09162-0
Int J Mol Sci. 2025 May 22. pii: 4968. [Epub ahead of print]26(11):

Upregulation of Sulfated N-Glycans in Serum as Predictive Biomarkers for Early-Stage Breast Cancer.

Dereje G Feleke, Bryan M Montalban, Solomon T Gizaw, Hiroshi Hinou.

  Breast cancer (BC) is a major global health concern, and early detection is key to improving patient outcomes. Aberrant glycosylation, particularly the sulfation of glycans, is implicated in cancer progression; however, analyzing these low-abundance glycans is challenging. This study aimed to profile serum sulfated N-glycans in Ethiopian patients with BC to identify novel biomarkers for the early detection of BC. Using a glycoblotting-based sulphoglycomics workflow, including high-throughput glycoblotting enrichment, weak anion exchange (WAX) separation, and MALDI-TOF MS, serum samples from 76 BC patients and 20 healthy controls were analyzed. Statistical evaluation revealed significant differences in the sulfated N-glycan profiles. Seven mono-sulfated N-glycans were markedly elevated in patients with BC, demonstrating high diagnostic accuracy (AUC ≥ 0.8) in this internal cohort. Terminal Lewis-type glycan epitopes were prominent in sulfated glycans but were absent in their non-sulfated counterparts. The increased fucosylation and sialylation of sulfated glycans are statistically significant markers of early-stage BC. The preservation of sialic acid groups during the analysis ensured detailed structural insight. This pioneering study quantitatively examined sulfated N-glycans in BC and identified potential glyco-biomarkers for early detection. Validation in larger, diverse cohorts is needed to establish their broader diagnostic relevance and improve our understanding of cancer-associated glycomic alterations.

Keywords:  MALDI-TOF MS; biomarkers; breast cancer; early detection; glycoblotting; sulfated N-glycans

DOI:  https://doi.org/10.3390/ijms26114968
Noncoding RNA Res. 2025 Aug;13 121-130

Uremic toxins levels are associated with miR-223 in chronic kidney disease-associated anemia.

Emma Brisot, Pierre-Marie Leprêtre, Eya Hamza, Ophélie Fourdinier, Benjamin Brigant, Hakim Ouled-Haddou, Gabriel Choukroun, Ziad A Massy, Francis Verbeke, Valérie Metzinger-Le Meuth, Griet Glorieux, Laurent Metzinger.

  Chronic kidney disease (CKD) poses a significant threat, with increased rates of cardiovascular and all-cause mortality. Anemia, common in CKD, is associated with accumulation of uremic toxins in the bloodstream. We previously demonstrated that the uremic toxin indoxyl sulfate (IS) impacts the regulation of erythropoiesis in cellular and preclinical CKD models. Here, the role of non-coding RNAs in this toxic effect was evaluated. The effect of IS on microRNA expression was measured in human erythropoietic cell line UT7/EPO, using nanostring. We found a significant increase of miR-223 in cells treated with IS. This finding was further validated in human primary CD34+ cells, a more physiological model for human erythropoiesis. Finally, serum levels of miR-223 correlated with representative uremic toxins, including IS, in patients with various stages of CKD, and also with endothelial dysfunction markers, indicating a link with vascular damage. These correlations varied according to erythropoietin treatment and dialysis. These findings suggest that miR-223 may play a role in the development of anemia in CKD. Further investigation into the involvement of miR-223 in erythropoiesis is needed for a better understanding of the mechanisms underlying anemia in CKD and the potential role of uremic toxins. Ultimately, this may open up new therapeutic possibilities for the management of anemia in CKD.

Keywords:  Biomarker; Chronic kidney disease; Erythropoiesis; MicroRNA; Red blood cell; Uremic toxin; miR-223

DOI:  https://doi.org/10.1016/j.ncrna.2025.04.009
Biomed Rep. 2025 Aug;23(2): 123

Effect of Gracilaria fisheri sulfated galactan with increased sulfation on cell migration and expression of cell adhesion molecules in sodium oxalate-induced HK-2 cell injury.

Tawut Rudtanatip, Jenjiralai Phanphak, Somsuda Somintara, Jamal El-Abid, Kanokpan Wongprasert, José Kovensky, Waraporn Sakaew.

  Exposure to oxalate crystals causes cellular injury and dysfunction in the renal tubular epithelium. Sulfated galactan with increased sulfation (SGS) from the red seaweed Gracilaria fisheri exhibits anti-urolithiasis effects by inhibiting oxalate crystal formation and preventing sodium oxalate (NaOX)-induced death of renal tubular (HK-2) cells. However, the effects of SGS on wound healing and adhesion molecule expression in NaOX-induced HK-2 cell injury remain unexplored. The present study investigated the effects of SGS on wound healing and the regulation of adhesion molecule expression in NaOX-induced HK-2 cell damage. The findings showed that SGS promoted wound healing in HK-2 cells following a scratch injury under NaOX-induced conditions. NaOX exposure increased the expression of CD44 and vimentin while decreasing the expression of EpCAM, E-cadherin, occludin and ZO-1, as demonstrated by reverse transcription-quantitative PCR, western blotting and immunofluorescence analysis. Treatment with SGS restored these adhesion molecule expression levels to near normal. Scanning electron microscopy revealed that SGS also reversed NaOX-induced morphological changes in HK-2 cells. Additionally, SGS reduced the expression of Akt and p38 while upregulating PI3K and Erk1/2 in NaOX-treated HK-2 cells. These results suggested that SGS enhances wound healing and regulates the expression of adhesion molecules, possibly through the PI3K/Akt and MAPK (p38 and Erk1/2) signaling pathways, highlighting the potential of SGS as a promising therapeutic compound for preventing and treating NaOX-induced renal damage.

Keywords:  adhesion molecules; cell migration; human kidney cells; sodium oxalate; sulfation of sulfated galactan

DOI:  https://doi.org/10.3892/br.2025.2001
J Biol Chem. 2025 Jun 07. pii: S0021-9258(25)02204-5. [Epub ahead of print] 110354

Analysis of chondroitin degradation by components of a Bacteroides caccae polysaccharide utilization locus.

Bernadette Alvarez, Olivia F Canil, Kristin E Low, Andrew G Hettle, D Wade Abbott, Alisdair B Boraston.

The human gut microbiota (HGM) possesses enormously diverse capacity to metabolize both host and dietary glycans. Glycosaminoglycans (GAG) are complex polysaccharides that may be in the diet (e.g., from animal products) or may be presented by host tissues. These polysaccharides are known to be prioritized as a nutrient source by some members of the HGM. While significant advances in understanding how GAGs are metabolized by the HGM have been made, the varied architectures of the numerous polysaccharide utilization loci (PULs) targeting varied polysaccharides suggest that all the mechanisms of GAG degradation may not have been uncovered. Here we show that components of a (PUL) from Bacteroides caccae have activities consistent with comprising a unique pathway for depolymerization of chondroitin sulfate, a common GAG. After prior desulfation by an endo-sulfatase, BcSulf, to produce unsulfated chondroitin from chondroitin, the depolymerization pathway begins with the activity a polysaccharide lyase from family 35, BcPL35. BcPL35 activity is coupled with BcGH88, an exo-β-uronyl hydrolase, and presumably BcGH109, a confirmed α/β-N-acetylgalactosaminidase. The most unique feature of the pathway is a β-D-glucuronate dehydratase, BcGDH, which we show through structural and functional analyses primes saturated non-reducing end β-D-glucuronate residues for hydrolysis by BcGH88. BcGDH is a member of a large family previously classified as glycoside hydrolase family 154. The potential reclassification of GH154 enzymes as uronate sugar dehydratases not only improves our understanding of chondroitin metabolism by B. caccae but will be broadly applicable to predicting the function of other pathways relevant to uronate sugar metabolism.

DOI: https://doi.org/10.1016/j.jbc.2025.110354
J Agric Food Chem. 2025 Jun 12.

Characterization of an Endo-1,3-fucanase from Glycoside Hydrolase Family 187 Within a Polysaccharide Utilization Locus of Wenyingzhuangia aestuarii OF219.

Guangning Chen, Jingjing Shen, Xinyu Li, Ziyue Yan, Changhu Xue, Yaoguang Chang.

  Sulfated fucan is a bioactive component prevalent in brown algae and echinoderms. Endo-1,3-fucanase plays a pivotal role in the structure analysis and oligosaccharide preparation of sulfated fucans. However, the action mode and molecular mechanism of endo-1,3-fucanase remain largely unexplored. This study identified a new endo-1,3-fucanase Fun187B within the GH187 family, which exhibits only a 26.2% sequence identity to the sole characterized member of the family (Fun187A). Fun187B could cleave sulfated fucan from Thelenota ananas in an endoacting mode and produced the trisaccharide α-l-Fucp2(OSO3-)-1→3-α-l-Fucp-1→3-α-l-Fucp2(OSO3-) as the major product, which is distinct from Fun187A. Structure prediction by Alphafold3 combined with molecular docking showed that Fun187B recognized the substrate through a series of polar amino acids. The structural analogues of Fun187B are widely distributed among polysaccharide-degrading specialized bacteria. This study provides novel perspectives on the GH187 endo-1,3-fucanase, introducing a favorable tool for enhancing investigations and applications associated with sulfated fucans.

Keywords:  GH187; action mode; fucanase; glycoside hydrolase; sulfated fucan

DOI:  https://doi.org/10.1021/acs.jafc.5c03084
World J Diabetes. 2025 May 15. 16(5): 102196

Shenfushu granules attenuate diabetic kidney disease by inhibiting PIK3R1/protein kinase B/heparanase-mediated endothelial-mesenchymal transition.

Xi-Ding Yang, Si-Jia Ma, Da-Xiong Xiang, Yong-Yu Yang.

   BACKGROUND: Injury to the glomerular filtration barrier causes diabetic kidney disease (DKD), and glomerular endothelial-mesenchymal transition damages the filtration barrier of glomerular endothelial cells. Shenfushu granules (SFSGs) can treat chronic renal failure; however, their role and mechanism in DKD remain unclear.
AIM: To investigate the role of SFSGs in delaying DKD progression and their underlying mechanism in a streptozotocin-induced DKD mouse model.
METHODS: The microalbumin content in the urine and the blood glucose, creatinine, and blood urea nitrogen levels in the serum were measured. The expression and distribution of α-smooth muscle actin (α-SMA), heparan sulfate (HS) and cluster of differentiation (CD) 31 were observed through immunofluorescence or immunohistochemistry. Western blotting was conducted to measure the expression of CD31, α-SMA, PIK3R1, protein kinase B (AKT), phospho-PIK3R1, phospho-AKT, and heparanase-1. Network pharmacology was conducted to screen and identify the core components and targets of SFSGs. Molecular docking and dynamic simulations were performed to evaluate the binding ability of the core components of SFSGs to their core targets.
RESULTS: Compared with those in the model group, the 24-hour microalbuminuria (188.2 ± 20.1 and 140.4 ± 24.7 vs 323.2 ± 44.4), serum creatinine (79.4 ± 2.6 and 68.7 ± 6.0 vs 110.2 ± 4.8), blood urea nitrogen (14.4 ± 1.1 and 13.1 ± 0.5 vs 19.5 ± 1.1), and renal index (20.3 ± 1.0 and 19.6 ± 0.8 vs 25.3 ± 1.7) were significantly lower in the SFSGs (2.08 and 4.16 g/kg/day extract)-treated DKD mice. SFSGs inhibited the downregulation of CD31 and the upregulation of α-SMA in the glomerular endothelial cells of DKD mice. Additionally, SFSGs suppressed the decrease in glycocalyx thickness and the expression of its component HS. Network pharmacology revealed that PIK3R1 was the core target of SFSGs. SFSGs markedly downregulate the expression of phospho-PIK3R1, phospho-AKT, and heparanase-1. However, the PIK3R1 agonist abolished the regulatory effect of SFSGs on the expression of CD31, α-SMA, and heparanase-1.
CONCLUSION: Collectively, these results suggest that SFSGs can significantly delay DKD progression and inhibit injury to the glycocalyx and the endothelial-mesenchymal transition of glomerular endothelial cells. This mechanism is related to PIK3R1/AKT/heparanase-1 signaling pathway regulation.

Keywords:  Diabetic kidney disease; Endothelial-mesenchymal transition; Glomerular filtration barrier; Glycocalyx; Heparanase-1; PIK3R1; Shenfushu granules

DOI:  https://doi.org/10.4239/wjd.v16.i5.102196
Am J Physiol Renal Physiol. 2025 Jun 11.

Indoxyl sulfate as a potential tubular function marker across kidney disease models.

Sabbir Ahmed, Shelley Chen, Jacqueline P F E Lucas, Sebastiaan N Knoppert, Rachel Harwood, João Faria, Paul J Besseling, Rolf W Sparidans, Roel Broekhuizen, Koen G C Westphal, Silvia M Mihăilă, Jaap A Joles, Roel Goldschmeding, Tri Q Nguyen, Bettina Wilm, Patricia Murray, Andreas F-P Sonnen, Karin G F Gerritsen, Rosalinde Masereeuw.

  Kidney tubular damage is a strong predictor of chronic kidney disease (CKD) progression. Tubular function involves nutrient reabsorption and active secretion via transporters, such as the organic anion transporters (OATs), to eliminate waste and metabolites, including protein bound uremic toxins (PBUTs). In tubular dysfunction, PBUTs accumulate in plasma which has been associated with many comorbidities. We hypothesized that PBUT plasma concentration and clearance are sensitive markers for tubular dysfunction. We evaluated this in experimental models of chronic (rat nephrectomy and mouse IRI) and acute (mouse and in vitro IRI) kidney disease. In 5/6th nephrectomy rats, plasma concentration and clearance of PBUTs correlated with urinary tubular injury markers (kidney injury molecule-1 (Kim-1), neutrophil gelatinase-associated lipocalin (NGAL), Beta-2-microglobuline (B2M) and cystatin C) better than with filtration markers (GFR and plasma creatinine, cystatin C and urea). Moreover, indoxyl sulfate (IS) plasma concentration and clearance correlated in the subgroup with the lowest tubular injury. In chronic IRI mice with mild to moderate injury, plasma IS and its clearance correlated with tubular atrophy scores, plasma NGAL and NGAL excretion, whereas filtration markers did not correlate. In acute IRI mice, IS and hippuric acid (HA) clearance correlated with plasma NGAL. Moreover, mass spectrometry imaging (MSI) analysis revealed higher cortical but lower medullary accumulation of IS in IRI mice kidneys compared to healthy controls, which was accompanied by a down regulation of proximal tubular transporters. After inducing IRI in vitro using a human kidney proximal tubule cell line, decreased OAT1-mediated transport of IS was confirmed. Together, these findings suggest that plasma IS and its clearance represent kidney transporters-related tubular function and may serve as sensitive clinical biomarkers for tubular dysfunction in kidney diseases.

Keywords:  Biomarkers; Indoxyl sulfate; Kidney disease; Kidney tubular function; Uremic toxins; experimental disease model; protein-bound uremic toxins;; tubular function marker; tubular injury

DOI:  https://doi.org/10.1152/ajprenal.00107.2025
Cells. 2025 Jun 03. pii: 833. [Epub ahead of print]14(11):

Transmembrane Protein-184A Interacts with Syndecan-4 and Rab GTPases and Is Required to Maintain VE-Cadherin Levels.

Leanna M Altenburg, Stephanie H Wang, Grace O Ciabattoni, Amelia Kennedy, Rachel L O'Toole, Sara L N Farwell, M Kathryn Iovine, Linda J Lowe-Krentz.

  VE-cadherin (VE-cad) membrane stability and localization regulates adhesion formation and actin cytoskeleton dynamics in angiogenesis and vascular remodeling and requires the heparan sulfate proteoglycan (HSPG), Syndecan-4 (Sdc4). This study characterizes the interactions of the heparin receptor, Transmembrane protein-184A (TMEM184A), and Sdc4 in bovine aortic endothelial cells (BAOECs) and the regenerating Zebrafish (ZF) caudal fin and measures the effect of siRNA TMEM184A KD (siTMEM) and TMEM184A overexpression (TMEM OE) on VE-cad levels and localization in confluent and sub-confluent cultured BAOECs. Additionally, we examined the effect of siTMEM on key Rab GTPase trafficking regulators and migrating BAOECs in scratch wound healing assays. We demonstrated that TMEM184A and Sdc4 colocalize in BAOECs and that Sdc4 OE increases colocalization in an HS chain dependent manner, while both Tmem184a and Sdc4 cooperate synergistically in ZF fin angiogenic and tissue repair. We also showed that siTMEM decreases VE-cad membrane and cytoplasmic levels, while increasing scratch wound migration rates. However, TMEM OE cells show increased vesicle formation and VE-cad trafficking and membrane recovery. These findings characterize TMEM184A-Sdc4 cooperation in angiogenesis and indicate a dual function of TMEM184A in signaling and trafficking in vascular cells that promotes VE-cad recovery and membrane localization.

Keywords:  TMEM184A; VE-cadherin; angiogenesis; endothelial cells; syndecan-4

DOI:  https://doi.org/10.3390/cells14110833