Loss of mucin-type O-glycans impairs the integrity of the glomerular filtration barrier in the mouse kidney

Co-administration of angiotensin II and simvastatin triggers kidney injury upon heme oxygenase-1 deficiency

Kidneys are pivotal organ in iron redistribution and can be severely damaged in the course of hemolysis. In our previous studies, we observed that induction of hypertension with angiotensin II (Ang II) combined with simvastatin administration results in a high mortality rate or the appearance of signs of kidney failure in heme oxygenase-1 knockout (HO-1 KO) mice. Here, we aimed to address the mechanisms underlying this effect, focusing on heme and iron metabolism. We show that HO-1 deficiency leads to iron accumulation in the renal cortex. Higher mortality of Ang II and simvastatin-treated HO-1 KO mice coincides with increased iron accumulation and the upregulation of mucin-1 in the proximal convoluted tubules. In vitro studies showed that mucin-1 hampers heme- and iron-related oxidative stress through the sialic acid residues. In parallel, knock-down of HO-1 induces the glutathione pathway in an NRF2-depedent manner, which likely protects against heme-induced toxicity. To sum up, we showed that heme degradation during heme overload is not solely dependent on HO-1 enzymatic activity, but can be modulated by the glutathione pathway. We also identified mucin-1 as a novel redox regulator. The results suggest that hypertensive patients with less active HMOX1 alleles may be at higher risk of kidney injury after statin treatment.

Global Loss of Core 1-Derived O-Glycans in Mice Leads to High Mortality Due to Acute Kidney Failure and Gastric Ulcers

The core 1 structure is the major constituent of mucin-type O-glycans, which are added via glycosylation—a posttranslational modification present on membrane-bound and secretory proteins. Core 1 β1,3-galactosyltransferase (C1galt1), an enzyme that synthesizes the core 1 structure, requires Cosmc, a C1galt1-specific molecular chaperone, for its enzymatic activity. Since Cosmc-knockout mice exhibit embryonic lethality, the biological role of core 1-derived O-glycans in the adult stage is not fully understood. We generated ubiquitous and inducible CAGCre-ER^TM/Cosmc-knockout (iCAG-Cos) mice to investigate the physiological function of core 1-derived O-glycans. The iCAG-Cos mice exhibited a global loss of core 1-derived O-glycans, high mortality, and showed a drastic reduction in weights of the thymus, adipose tissue, and pancreas 10 days after Cosmc deletion. They also exhibited leukocytopenia, thrombocytopenia, severe acute pancreatitis, and atrophy of white and brown adipose tissue, as well as spontaneous gastric ulcers and severe renal dysfunction, which were considered the causes underlying the high mortality of the iCAG-Cos mice. Serological analysis indicated the iCAG-Cos mice have lower blood glucose and total blood protein levels and higher triglyceride, high-density lipoprotein, and total cholesterol levels than the controls. These data demonstrate the importance of core 1-derived O-glycans for homeostatic maintenance in adult mice.

The Glomerular Endothelium Restricts Albumin Filtration

Inflammatory activation and/or dysfunction of the glomerular endothelium triggers proteinuria in many systemic and localized vascular disorders. Among them are the thrombotic microangiopathies, many forms of glomerulonephritis, and acute inflammatory episodes like sepsis and COVID-19 illness. Another example is the chronic endothelial dysfunction that develops in cardiovascular disease and in metabolic disorders like diabetes. While the glomerular endothelium is a porous sieve that filters prodigious amounts of water and small solutes, it also bars the bulk of albumin and large plasma proteins from passing into the glomerular filtrate. This endothelial barrier function is ascribed predominantly to the endothelial glycocalyx with its endothelial surface layer, that together form a relatively thick, mucinous coat composed of glycosaminoglycans, proteoglycans, glycolipids, sialomucins and other glycoproteins, as well as secreted and circulating proteins. The glycocalyx/endothelial surface layer not only covers the glomerular endothelium; it extends into the endothelial fenestrae. Some glycocalyx components span or are attached to the apical endothelial cell plasma membrane and form the formal glycocalyx. Other components, including small proteoglycans and circulating proteins like albumin and orosomucoid, form the endothelial surface layer and are bound to the glycocalyx due to weak intermolecular interactions. Indeed, bound plasma albumin is a major constituent of the endothelial surface layer and contributes to its barrier function. A role for glomerular endothelial cells in the barrier of the glomerular capillary wall to protein filtration has been demonstrated by many elegant studies. However, it can only be fully understood in the context of other components, including the glomerular basement membrane, the podocytes and reabsorption of proteins by tubule epithelial cells. Discovery of the precise mechanisms that lead to glycocalyx/endothelial surface layer disruption within glomerular capillaries will hopefully lead to pharmacological interventions that specifically target this important structure.

Cosmc transfection decreases malignant behavior of Tn+ cells and enhances sensitivity to apoptosis when induced by Apo2L/TRAIL via alteration of O-glycan structure

Cosmc mutations may cause abnormal O-glycosylation and result in Tn antigen expression. In the current study, it was discovered that proliferation and migration of Tn+ cells (Jurkat T and LS174T-Tn⁺ cells) with mutant Cosmc decreased after transfected Cosmc, and their sensitivity to apoptosis induced by Apo2L/TRAIL increased. Core 1-, 2-, and 3-derived O-glycans were absent in Tn⁺ cells. After Cosmc transfection, normal extended core 1-derived O-glycans appeared and were accompanied by increased T-synthase activity. Core 2-derived O-glycans appeared in transfected LS174T-Tn⁺ cells, and their structural types and levels were lower than those in LS174T-Tn⁻ cells. Core 3-derived O-glycans were present only in LS174T-Tn⁻ cells. The activity of C3GnT in LS174T-Tn⁺ cells was lower than that in LS174T-Tn⁻ cells, and it was absent in Jurkat T cells. Cosmc transfection did not alter C3GnT activity or core 3-derived O-glycans in Jurkat T and LS174T-Tn⁺ cells. The results demonstrated that the composition and structure of O-glycans were different among various Tn⁺ cells, which not only affected cell malignant behavior but also modulated sensitivity to apoptotic stimuli. Thus, Cosmc transfection may effectively decrease the malignant behavior of Tn⁺ tumor cells and enhance their sensitivity to apoptosis when induced by Apo2L/TRAIL through modification of O-glycans.

Glycocalyx Curving the Membrane: Forces Emerging from the Cell Exterior

Morphological transitions are typically attributed to the actions of proteins and lipids. Largely overlooked in membrane shape regulation is the glycocalyx, a pericellular membrane coat that resides on all cells in the human body. Comprised of complex sugar polymers known as glycans as well as glycosylated lipids and proteins, the glycocalyx is ideally positioned to impart forces on the plasma membrane. Large, unstructured polysaccharides and glycoproteins in the glycocalyx can generate crowding pressures strong enough to induce membrane curvature. Stress may also originate from glycan chains that convey curvature preference on asymmetrically distributed lipids, which are exploited by binding factors and infectious agents to induce morphological changes. Through such forces, the glycocalyx can have profound effects on the biogenesis of functional cell surface structures as well as the secretion of extracellular vesicles. In this review, we discuss recent evidence and examples of these mechanisms in normal health and disease.

Piperazine ferulate prevents high-glucose-induced filtration barrier injury of glomerular endothelial cells

Filtration barrier injury induced by high glucose (HG) levels leads to the development of diabetic nephropathy. The endothelial glycocalyx plays a critical role in glomerular barrier function. In the present study, the effects of piperazine ferulate (PF) on HG-induced filtration barrier injury of glomerular endothelial cells (GEnCs) were investigated and the underlying mechanism was assessed. Immunofluorescence was used to observe the distribution of the glycocalyx as well as the expression levels of syndecan-1 and Zonula occludens-1 (ZO-1). Endothelial permeability assays were performed to assess the effects of PF on the integrity of the filtration barrier. Protein and mRNA expression levels were measured by western blotting and reverse transcription-quantitative PCR analyses, respectively. In vitro experiments revealed that adenosine monophosphate-activated protein kinase (AMPK) mediated HG-induced glycocalyx degradation and endothelial barrier injury. PF inhibited the HG-induced endothelial barrier injury and restored the expression levels of heparanase-1 (Hpa-1), ZO-1 and occludin-1 by AMPK. In vivo assays demonstrated that PF reduced the expression levels of Hpa-1, increased the expression levels of ZO-1 and attenuated glycocalyx degradation in the glomerulus. These data suggested that PF attenuated HG-induced filtration barrier injury of GEnC by regulating AMPK expression.

Mucin-Type O-GalNAc Glycosylation in Health and Disease

Mucin-type GalNAc O-glycosylation is one of the most abundant and unique post-translational modifications. The combination of proteome-wide mapping of GalNAc O-glycosylation sites and genetic studies with knockout animals and genome-wide analyses in humans have been instrumental in our understanding of GalNAc O-glycosylation. Combined, such studies have revealed well-defined functions of O-glycans at single sites in proteins, including the regulation of pro-protein processing and proteolytic cleavage, as well as modulation of receptor functions and ligand binding. In addition to isolated O-glycans, multiple clustered O-glycans have an important function in mammalian biology by providing structural support and stability of mucins essential for protecting our inner epithelial surfaces, especially in the airways and gastrointestinal tract. Here the many O-glycans also provide binding sites for both endogenous and pathogen-derived carbohydrate-binding proteins regulating critical developmental programs and helping maintain epithelial homeostasis with commensal organisms. Finally, O-glycan changes have been identified in several diseases, most notably in cancer and inflammation, where the disease-specific changes can be used for glycan-targeted therapies. This chapter will review the biosynthesis, the biology, and the translational perspectives of GalNAc O-glycans.

The Detection of Plasma Soluble Podoplanin of Patients with Breast Cancer and Its Clinical Signification

Background

Podoplanin (PDPN) is a type-1 membrane sialoglycoprotein that is expressed in many cancer tumors including breast cancer; nonetheless, its roles in tumor occurrence, development, and metastasis are unclear. In this study, we aimed to investigate the clinical significance of plasma soluble PDPN (sPDPN) levels in patients with breast cancer and its significance in the diagnosis and metastasis.

Materials and Methods

Blood samples from healthy controls (CTL), patients with fibroadenomas of breast (FOB), and breast cancer (pathological type: invasive ductal carcinoma, IDC) were collected. sPDPN levels in the plasma of CTL and patients with FOB and IDC were measured by the ELISA.

Results

The plasma sPDPN levels in IDC patients (159 cases, 22.59±3.70 ng/mL) were higher than those in FOB patients (50 cases, 8.29±1.09 ng/mL; P<0.05) and CTL (100 cases, 1.21±0.12 ng/mL; P<0.0001). The sPDPN levels in patients at stage III and stage IV (30.08±4.66 ng/mL) were higher than in patients at stage I and stage II (11.84±1.12 ng/mL; P=0.005). The sPDPN levels in patients with high-moderate and moderate differentiation (17.50±3.02 ng/mL) were lower than those in patients with moderately low and low differentiation (35.73±4.26 ng/mL; P=0.026). The sPDPN levels in patients with metastasis (30.60±4.27 ng/mL) were much higher than those in patients without metastasis (13.02±1.30 ng/mL; P=0.017).

Conclusion

Plasma sPDPN may be used as a new marker for the determination of the clinical stage, differentiation degree, and metastasis status of breast cancer.

Genomic history of the Italian population recapitulates key evolutionary dynamics of both Continental and Southern Europeans

BACKGROUND

The cline of human genetic diversity observable across Europe is recapitulated at a micro-geographic scale by variation within the Italian population. Besides resulting from extensive gene flow, this might be ascribable also to local adaptations to diverse ecological contexts evolved by people who anciently spread along the Italian Peninsula. Dissecting the evolutionary history of the ancestors of present-day Italians may thus improve the understanding of demographic and biological processes that contributed to shape the gene pool of European populations. However, previous SNP array-based studies failed to investigate the full spectrum of Italian variation, generally neglecting low-frequency genetic variants and examining a limited set of small effect size alleles, which may represent important determinants of population structure and complex adaptive traits. To overcome these issues, we analyzed 38 high-coverage whole-genome sequences representative of population clusters at the opposite ends of the cline of Italian variation, along with a large panel of modern and ancient Euro-Mediterranean genomes.

RESULTS

We provided evidence for the early divergence of Italian groups dating back to the Late Glacial and for Neolithic and distinct Bronze Age migrations having further differentiated their gene pools. We inferred adaptive evolution at insulin-related loci in people from Italian regions with a temperate climate, while possible adaptations to pathogens and ultraviolet radiation were observed in Mediterranean Italians. Some of these adaptive events may also have secondarily modulated population disease or longevity predisposition.

CONCLUSIONS

We disentangled the contribution of multiple migratory and adaptive events in shaping the heterogeneous Italian genomic background, which exemplify population dynamics and gene-environment interactions that played significant roles also in the formation of the Continental and Southern European genomic landscapes.

Mice lacking core 1-derived O-glycan in podocytes develop transient proteinuria, resulting in focal segmental glomerulosclerosis

The glomerular filtration barrier is composed of podocytes, glomerular basement membrane, and endothelial cells. Disruption of these structures causes several glomerular injuries, such as focal segmental glomerulosclerosis (FSGS). The surface of podocyte apical membranes is coated by negatively charged sialic acids on core 1-derived mucin-type O-glycans. Here, we aimed to investigate the physiological role of core 1-derived O-glycans in the podocytes using adult mice lacking podocyte-specific core 1-derived O-glycans (iPod-Cos). iPod-Cos mice exhibited early and transient proteinuria with foot process effacements and developed typical FSGS-like disease symptoms. To identify the key molecules responsible for the FSGS-like phenotype, we focused on podocalyxin and podoplanin, which possess mucin-type O-glycans. Expression and localization of podocalyxin did not change in iPod-Cos glomeruli. Besides, western blot analysis revealed significantly lower levels of intact podocalyxin in isolated glomeruli of iPod-Cos mice, and high levels of processed forms in iPod-Cos glomeruli, as compared to that in control glomeruli. Conversely, podoplanin mRNA, and protein levels were lower in iPod-Cos mice than in control mice. These results demonstrated that core 1-derived O-glycan on podocytes is required for normal glomerular filtration and may contribute to the stable expression of podocalyxin and podoplanin.

Cosmc-dependent mucin-type O-linked glycosylation is essential for podocyte function

Mucin-type O-linked glycosylation, a posttranslational modification affecting the stability and biophysical characteristics of proteins, requires C1GalT1 (T synthase) and its obligate, X-linked chaperone Cosmc. Hypomorphic C1GalT1 mutations cause renal failure via not yet established mechanisms. We hypothesize that impaired Cosmc-dependent O-glycosylation in podocytes is sufficient to cause disease. Podocyte-specific Cosmc knockout mice were generated and phenotyped to test this hypothesis. Female heterozygous mice displaying mosaic inactivation of Cosmc in podocytes due to random X-linked inactivation were also examined. Mice with podocyte-specific Cosmc deletion develop profound albuminuria, foot process effacement, glomerular sclerosis, progressive renal failure, and impaired survival. Glomerular transcriptome analysis reveals early changes in cell adhesion, extracellular matrix organization, and chemokine-mediated signaling pathways, coupled with podocyte loss. Expression of the O-glycoprotein podoplanin was lost, while Tn antigen, representing immature O-glycans, was most abundantly found on podocalyxin. In contrast to hemizygous male and homozygous female animals, heterozygous female mosaic animals developed only mild albuminuria, focal foot process effacement, and nonprogressive kidney disease. Ultrastructurally, Cosmc-deficient podocytes formed Tn antigen-positive foot processes interdigitating with those of normal podocytes but not with other Cosmc-deficient cells. This suggests a cell nonautonomous mechanism for mucin-type O-glycoproteins in maintaining podocyte function. In summary, our findings demonstrated an essential and likely cell nonautonomous role for mucin-type O-glycosylation for podocyte function.

Growth hormone induces Notch1 signaling in podocytes and contributes to proteinuria in diabetic nephropathy

Growth hormone (GH) plays a significant role in normal renal function and overactive GH signaling has been implicated in proteinuria in diabetes and acromegaly. Previous results have shown that the glomerular podocytes, which play an essential role in renal filtration, express the GH receptor, suggesting the direct action of GH on these cells. However, the exact mechanism and the downstream pathways by which excess GH leads to diabetic nephropathy is not established. In the present article, using immortalized human podocytes in vitro and a mouse model in vivo, we show that excess GH activates Notch1 signaling in a γ-secretase-dependent manner. Pharmacological inhibition of Notch1 by γ-secretase inhibitor DAPT (N-[N-(3,5-Difluorophenacetyl)-l-alanyl]-S-phenyl glycine t-butylester) abrogates GH-induced epithelial to mesenchymal transition (EMT) and is associated with a reduction in podocyte loss. More importantly, our results show that DAPT treatment blocks cytokine release and prevents glomerular fibrosis, all of which are induced by excess GH. Furthermore, DAPT prevented glomerular basement membrane thickening and proteinuria induced by excess GH. Finally, using kidney biopsy sections from people with diabetic nephropathy, we show that Notch signaling is indeed up-regulated in such settings. All these results confirm that excess GH induces Notch1 signaling in podocytes, which contributes to proteinuria through EMT as well as renal fibrosis. Our studies highlight the potential application of γ-secretase inhibitors as a therapeutic target in people with diabetic nephropathy.

"Stuck on sugars - how carbohydrates regulate cell adhesion, recognition, and signaling"

We have explored the fundamental biological processes by which complex carbohydrates expressed on cellular glycoproteins and glycolipids and in secretions of cells promote cell adhesion and signaling. We have also explored processes by which animal pathogens, such as viruses, bacteria, and parasites adhere to glycans of animal cells and initiate disease. Glycans important in cell signaling and adhesion, such as key O-glycans, are essential for proper animal development and cellular differentiation, but they are also involved in many pathogenic processes, including inflammation, tumorigenesis and metastasis, and microbial and parasitic pathogenesis. The overall hypothesis guiding these studies is that glycoconjugates are recognized and bound by a growing class of proteins called glycan-binding proteins (GBPs or lectins) expressed by all types of cells. There is an incredible variety and diversity of GBPs in animal cells involved in binding N- and O-glycans, glycosphingolipids, and proteoglycan/glycosaminoglycans. We have specifically studied such molecular determinants recognized by selectins, galectins, and many other C-type lectins, involved in leukocyte recruitment to sites of inflammation in human tissues, lymphocyte trafficking, adhesion of human viruses to human cells, structure and immunogenicity of glycoproteins on the surfaces of human parasites. We have also explored the molecular basis of glycoconjugate biosynthesis by exploring the enzymes and molecular chaperones required for correct protein glycosylation. From these studies opportunities for translational biology have arisen, involving production of function-blocking antibodies, anti-glycan specific antibodies, and synthetic glycoconjugates, e.g. glycosulfopeptides, that specifically are recognized by GBPs. This invited short review is based in part on my presentation for the IGO Award 2019 given by the International Glycoconjugate Organization in Milan.

The first identified heterozygous nonsense mutations in podocalyxin offer new perspectives on the biology of podocytopathies

In the last two decades, our understanding of the genetic underpinnings of inherited podocytopathies has advanced immensely. By sequencing the genomes of a large pool of families affected by focal segmental glomerulosclerosis (FSGS), researchers have identified a common theme: familial podocytopathies are frequently caused by genes selectively expressed in podocytes. Podocalyxin is a podocyte-specific surface sialomucin that has long been known to play important roles in podocyte morphogenesis and function. Few studies, however, have shown a conclusive link between mutations in the gene and FSGS complemented by functional evidence. In a fascinating new paper published in Clinical Science, Lin et al. identify two unrelated pedigrees in which dominant loss-of-function mutations in PODXL lead to adult-onset FSGS. Nonsense-mediated decay of the mutated PODXL transcripts leads to protein insufficiency, which in turn cause podocyte dysfunction through defects in motility and cytoskeletal organization. This is the first study to date that demonstrates, mechanistically, how autosomal dominant mutations in podocalyxin can lead to FSGS and renal insufficiency. Here, we summarize the experimental findings of this manuscript and propose, perhaps, a more controversial hypothesis: down-regulation of podocalyxin protein expression from podocytes is a critical turning point in the progression of most podocytopathies and may be mechanistically relevant to glomerulopathies in which podocyte damage is not necessarily induced by genetic lesions.

Functional significance of the platelet immune receptors GPVI and CLEC-2

Although platelets are best known for their role in hemostasis, they are also crucial in development, host defense, inflammation, and tissue repair. Many of these roles are regulated by the immune-like receptors glycoprotein VI (GPVI) and C-type lectin receptor 2 (CLEC-2), which signal through an immunoreceptor tyrosine-based activation motif (ITAM). GPVI is activated by collagen in the subendothelial matrix, by fibrin and fibrinogen in the thrombus, and by a remarkable number of other ligands. CLEC-2 is activated by the transmembrane protein podoplanin, which is found outside of the vasculature and is upregulated in development, inflammation, and cancer, but there is also evidence for additional ligands. In this Review, we discuss the physiological and pathological roles of CLEC-2 and GPVI and their potential as targets in thrombosis and thrombo-inflammatory disorders (i.e., disorders in which inflammation plays a critical role in the ensuing thrombosis) relative to current antiplatelet drugs.

Probing the contribution of individual polypeptide GalNAc-transferase isoforms to the O-glycoproteome by inducible expression in isogenic cell lines

The GalNAc-type O-glycoproteome is orchestrated by a large family of polypeptide GalNAc-transferase isoenzymes (GalNAc-Ts) with partially overlapping contributions to the O-glycoproteome besides distinct nonredundant functions. Increasing evidence indicates that individual GalNAc-Ts co-regulate and fine-tune specific protein functions in health and disease, and deficiencies in individual GALNT genes underlie congenital diseases with distinct phenotypes. Studies of GalNAc-T specificities have mainly been performed with in vitro enzyme assays using short peptide substrates, but recently quantitative differential O-glycoproteomics of isogenic cells with and without GALNT genes has enabled a more unbiased exploration of the nonredundant contributions of individual GalNAc-Ts. Both approaches suggest that fairly small subsets of O-glycosites are nonredundantly regulated by specific GalNAc-Ts, but how these isoenzymes orchestrate regulation among competing redundant substrates is unclear. To explore this, here we developed isogenic cell model systems with Tet-On inducible expression of two GalNAc-T genes, GALNT2 and GALNT11, in a knockout background in HEK293 cells. Using quantitative O-glycoproteomics with tandem-mass-tag (TMT) labeling, we found that isoform-specific glycosites are glycosylated in a dose-dependent manner and that induction of GalNAc-T2 or -T11 produces discrete glycosylation effects without affecting the major part of the O-glycoproteome. These results support previous findings indicating that individual GalNAc-T isoenzymes can serve in fine-tuned regulation of distinct protein functions.

Loss of complex O-glycosylation impairs exocrine pancreatic function and induces MODY8-like diabetes in mice

Cosmc is ubiquitously expressed and acts as a specific molecular chaperone assisting the folding and stability of core 1 synthase. Thus, it plays a crucial role in the biosynthesis of O-linked glycosylation of proteins. Here, we show that ablation of Cosmc in the exocrine pancreas of mice causes expression of truncated O-glycans (Tn antigen), resulting in exocrine pancreatic insufficiency with decreased activities of digestive enzymes and diabetes. To understand the molecular causes of the pleiotropic phenotype, we used Vicia villosa agglutinin to enrich Tn antigen-modified proteins from Cosmc-KO pancreatic lysates and performed a proteomic analysis. Interestingly, a variety of proteins were identified, of which bile salt-activated lipase (also denoted carboxyl-ester lipase, Cel) was the most abundant. In humans, frameshift mutations in CEL cause maturity-onset diabetes of the young type 8 (MODY8), a monogenic syndrome of diabetes and pancreatic exocrine dysfunction. Here, we provide data suggesting that differentially O-glycosylated Cel could negatively affect beta cell function. Taken together, our findings demonstrate the importance of correct O-glycan formation for normal exocrine and endocrine pancreatic function, implying that aberrant O-glycans might be relevant for pathogenic mechanisms of the pancreas.

Identification of Novel Urinary Biomarkers for Predicting Renal Prognosis in Patients With Type 2 Diabetes by Glycan Profiling in a Multicenter Prospective Cohort Study: U-CARE Study 1

OBJECTIVE

Because quantifying glycans with complex structures is technically challenging, little is known about the association of glycosylation profiles with the renal prognosis in diabetic kidney disease (DKD).

RESEARCH DESIGN AND METHODS

In 675 patients with type 2 diabetes, we assessed the baseline urinary glycan signals binding to 45 lectins with different specificities. The end point was a decrease of estimated glomerular filtration rate (eGFR) by ≥30% from baseline or dialysis for end-stage renal disease.

RESULTS

During a median follow-up of 4.0 years, 63 patients reached the end point. Cox proportional hazards analysis revealed that urinary levels of glycans binding to six lectins were significantly associated with the outcome after adjustment for known indicators of DKD, although these urinary glycans, except that for DBA, were highly correlated with baseline albuminuria and eGFR. Hazard ratios for these lectins were (+1 SD for the glycan index) as follows: SNA (recognizing glycan Siaα2-6Gal/GalNAc), 1.42 (95% CI 1.14-1.76); RCA120 (Galβ4GlcNAc), 1.28 (1.01-1.64); DBA (GalNAcα3GalNAc), 0.80 (0.64-0.997); ABA (Galβ3GalNAc), 1.29 (1.02-1.64); Jacalin (Galβ3GalNAc), 1.30 (1.02-1.67); and ACA (Galβ3GalNAc), 1.32 (1.04-1.67). Adding these glycan indexes to a model containing known indicators of progression improved prediction of the outcome (net reclassification improvement increased by 0.51 [0.22-0.80], relative integrated discrimination improvement increased by 0.18 [0.01-0.35], and the Akaike information criterion decreased from 296 to 287).

CONCLUSIONS

The urinary glycan profile identified in this study may be useful for predicting renal prognosis in patients with type 2 diabetes. Additional investigation of glycosylation changes and urinary glycan excretion in DKD is needed.

Podoplanin emerges as a functionally relevant oral cancer biomarker and therapeutic target

Oral cancer has become one of the most aggressive types of cancer, killing 140,000 people worldwide every year. Current treatments for oral cancer include surgery and radiation therapies. These procedures can be very effective; however, they can also drastically decrease the quality of life for survivors. New chemotherapeutic treatments are needed to more effectively combat oral cancer. The transmembrane receptor podoplanin (PDPN) has emerged as a functionally relevant oral cancer biomarker and chemotherapeutic target. PDPN expression promotes tumor cell migration leading to oral cancer invasion and metastasis. Here, we describe the role of PDPN in oral squamous cell carcinoma progression, and how it may be exploited to prevent and treat oral cancer.