Cell adhesion molecule-1 shedding induces apoptosis of renal epithelial cells and exacerbates human nephropathies

Apoptosis in kidney tissue of senior and geriatric cats with chronic kidney disease

Apoptosis, an important pathological event associated with kidney disease progression, is expected to be a therapeutic target in chronic kidney disease (CKD). However, its role in naturally occurring CKD in aged cats remains unclear. Therefore, here, we investigated kidney tissues from aged cats (≥10 years) with or without azotemic CKD to evaluate apoptotic events using a terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labeling (TUNEL) assay. The positive TUNEL signals of the renal cells were quantified and statistically analyzed for correlation with the severity of plasma creatinine (pCre) concentration, renal lesions (glomerulosclerosis, interstitial cell infiltration, peritubular capillaries, and interstitial fibrosis), and oxidative damage of the kidney tissue. Oxidative damage was evaluated using immunohistochemistry for 8-hydroxy-2'-deoxyguanosine (OHdG) and 4-hydroxynonenal (HNE). In the TUNEL assay, regardless of azotemia, positive nuclear signals were observed in the tubular epithelial and intraluminal cells, interstitial infiltrating cells, and glomerular cells. Quantitative TUNEL scores showed no significant differences between the azotemic and non-azotemic groups in any compartment of the kidney tissues. In the azotemic group, TUNEL scores did not correlate with pCre or renal lesion severity. However, the scores showed a significant positive correlation with the scores of 8-OHdG and 4-HNE. These findings suggest that apoptosis associated with oxidative damage in renal tissue is an initial pathological event that leads to CKD, rather than a change following CKD progression, in aged cats. Inhibiting apoptosis by antioxidant treatment may be a key strategy to prevent the development of CKD.

Multi-omic analysis of human kidney tissue identified medulla-specific gene expression patterns

The kidney medulla is a specialized region with important homeostatic functions. It has been implicated in genetic and developmental disorders along with ischemic and drug-induced injuries. Despite its role in kidney function and disease, the medulla's baseline gene expression and epigenomic signatures have not been well described in the adult human kidney. Here we generated and analyzed gene expression (RNA-seq), chromatin accessibility (ATAC-seq), chromatin conformation (Hi-C) and spatial transcriptomic data from the adult human kidney cortex and medulla. Tissue samples were obtained from macroscopically dissected cortex and medulla of tumor-adjacent normal material in nephrectomy specimens from five male patients. We used these carefully annotated specimens to reassign incorrectly labeled samples in the larger public Genotype-Tissue Expression (GTEx) Project, and to extract meaningful medullary gene expression signatures. Using integrated analysis of gene expression, chromatin accessibility and conformation profiles, we found insights into medulla development and function and then validated this by spatial transcriptomics and immunohistochemistry. Thus, our datasets provide a valuable resource for functional annotation of variants from genome-wide association studies and are freely accessible through an epigenome browser portal.

ADAM10 and ADAM17, Major Regulators of Chronic Kidney Disease Induced Atherosclerosis?

Chronic kidney disease (CKD) is a major health problem, affecting millions of people worldwide, in particular hypertensive and diabetic patients. CKD patients suffer from significantly increased cardiovascular disease (CVD) morbidity and mortality, mainly due to accelerated atherosclerosis development. Indeed, CKD not only affects the kidneys, in which injury and maladaptive repair processes lead to local inflammation and fibrosis, but also causes systemic inflammation and altered mineral bone metabolism leading to vascular dysfunction, calcification, and thus, accelerated atherosclerosis. Although CKD and CVD individually have been extensively studied, relatively little research has studied the link between both diseases. This narrative review focuses on the role of a disintegrin and metalloproteases (ADAM) 10 and ADAM17 in CKD and CVD and will for the first time shed light on their role in CKD-induced CVD. By cleaving cell surface molecules, these enzymes regulate not only cellular sensitivity to their micro-environment (in case of receptor cleavage), but also release soluble ectodomains that can exert agonistic or antagonistic functions, both locally and systemically. Although the cell-specific roles of ADAM10 and ADAM17 in CVD, and to a lesser extent in CKD, have been explored, their impact on CKD-induced CVD is likely, yet remains to be elucidated.

Role of renal tubular programed cell death in diabetic kidney disease

The pathogenic mechanism of diabetic kidney disease (DKD) is involved in various functions; however, its inadequate characterisation limits the availability of effective treatments. Tubular damage is closely correlated with renal function and is thought to be the main contributor to the injury observed in early DKD. Programed cell death (PCD) occurs during the biological development of the living body. Accumulating evidence has clarified the fundamental role of abnormalities in tubular PCD during DKD pathogenesis. Among PCD types, classical apoptosis, autophagic cell death, and pyroptosis are the most studied and will be the focus of this review. Our review aims to elucidate the current knowledge of the mechanism of DKD and the potential therapeutic potential of drugs targeting tubular PCD pathways in DKD.

Dezocine inhibits cell proliferation, migration, and invasion by targeting CRABP2 in ovarian cancer

Previous studies have shown that some anesthesia drugs can inhibit tumor growth and metastasis. As a clinical anesthetic drug, dezocine has been reported to play an important role in immune function. However, the effects of dezocine on ovarian cancer cell growth and metastasis are not fully understood. In this study, we found that dezocine dose-dependently inhibited the viability of ES-2 and SKOV3 cells. Dezocine suppressed the migration and invasion abilities of ovarian cancer cells, and promoted apoptosis. Moreover, the Akt/mTOR signaling pathway was also inhibited by dezocine. Furthermore, mechanism study showed that dezocine could significantly inhibit the expression of CRABP2, and CRABP2 overexpression reversed the inhibitory effects of dezocine on ovarian cancer cell proliferation and migration. In conclusion, dezocine has significant anti-tumor effects on the growth and metastatic potential of ovarian cancer cells, and CRABP2 functions as a downstream effector of dezocine.

Possible Therapeutic Utility of anti-Cell Adhesion Molecule 1 Antibodies for Malignant Pleural Mesothelioma

Malignant pleural mesothelioma (MPM) is a highly aggressive malignant tumor, and the effective therapeutic drugs are limited. Thus, the establishment of novel therapeutic method is desired. Considerable proportion of MPMs are shown to express cell adhesion molecule 1 (CADM1), and to use CADM1 to bind to and proliferate on the pleural mesothelial surface, suggesting that CADM1 is a possible therapeutic target. Here, anti-CADM1 ectodomain chicken monoclonal antibodies, 3E1 and 9D2, were examined for their possible therapeutic utility. The full-length form of CADM1 was expressed in eight out of twelve human MPM cell lines. MPM cell lines were cultured on a confluent monolayer of mesothelial MeT-5A cells in the presence of 9D2, the neutralizing antibody. 9D2 suppressed the cell growth of CADM1-positive MPM cells with the loss and aggregation of CADM1 molecules on the MPM cell membrane, but not of CADM1-negative MPM cells. Co-addition of 3E1, lacking the neutralizing action, enhanced the growth-suppressive effect of 9D2. The two antibodies were tested as drug delivery vectors. 3E1 was converted into a humanized antibody (h3E1) and conjugated with monomethyl auristatin E (MMAE), a tubulin polymerization inhibitor. When the resulting h3E1–MMAE antibody-drug conjugate (ADC) was added to the standard cultures of CADM1-positive MPM cells, it suppressed the cell growth in a dose-dependent manner. Co-addition of 9D2 enhanced the growth-suppressive effect of h3E1–MMAE ADC. Anti-CADM1 ectodomain antibodies were suggested to serve as both antibody drugs and drug vectors in the treatment of MPM.

α-Fetoprotein-Producing Endometrial Carcinoma Is Associated With Fetal Gut-Like and/or Hepatoid Morphology, Lymphovascular Infiltration, TP53 Abnormalities, and Poor Prognosis: Five Cases and Literature Review

The clinicopathological, immunohistochemical, and molecular characteristics of α-fetoprotein (AFP)-producing endometrial carcinoma (AFP+ EC) are poorly understood. From 284 cases of endometrial carcinoma in our pathology archive, we identified five cases (1.8%) of AFP+ EC with fetal gut–like (4/5) and/or hepatoid (2/5) morphology. All cases exhibited lymphovascular infiltration. In addition, 24 cases of endometrial carcinoma with elevated serum AFP levels were retrieved from the literature. The patient age ranged from 44 to 86 years (median: 63). Of 26 cases whose FIGO (International Federation of Gynecology and Obstetrics) stage and follow-up information was available (mean follow-up 24 months), 15 were stage I or II and 11 were stage III or IV. Even in stage I or II disease, death or relapse occurred in more than half of the patients (8/15). Detailed analysis of our five cases revealed that, on immunohistochemistry, AFP+ EC was positive for SALL4 (4/5), AFP (3/5), and HNF1β (4/5) in >50% of neoplastic cells and negative for estrogen and progesterone receptors (5/5), PAX8 (4/5), and napsin A (5/5). Four cases exhibited aberrant p53 immunohistochemistry and were confirmed to harbor TP53 mutations by direct sequencing. No mutation was found in POLE, CTNNB1, or KRAS. In conclusion, AFP+ EC merits recognition as a distinct subtype of endometrial carcinoma, which occurs in 1.8% of endometrial carcinoma cases, are associated with TP53 abnormalities, exhibit lymphovascular infiltration, and can show distant metastasis even when treated in early stage.

Brucella melitensis UGPase inhibits the activation of NF-κB by modulating the ubiquitination of NEMO

BACKGROUND

UTP-glucose-1-phosphoryl transferase (UGPase) catalyzes the synthesis of UDP-glucose, which is essential for generating the glycogen needed for the synthesis of bacterial lipopolysaccharide (LPS) and capsular polysaccharide, which play important roles in bacterial virulence. However, the molecular function of UGPase in Brucella is still unknown.

RESULTS

In this study, the ubiquitination modification of host immune-related protein in cells infected with UGPase-deleted or wild-type Brucella was analyzed using ubiquitination proteomics technology. The ubiquitination modification level and type of NF-κB Essential Modulator (NEMO or Ikbkg), a molecule necessary for NF-κB signal activation, was evaluated using Coimmunoprecipitation, Western blot, and dual-Luciferase Assay. We found 80 ubiquitin proteins were upregulated and 203 ubiquitin proteins were downregulated in cells infected with B. melitensis 16 M compared with those of B. melitensis UGPase-deleted strain (16 M-UGPase^-). Moreover, the ubiquitin-modified proteins were mostly enriched in the categories of regulation of kinase/NF-κB signaling and response to a bacterium, suggesting Brucella UGPase inhibits ubiquitin modification of related proteins in the host NF-κB signaling pathway. Further analysis showed that the ubiquitination levels of NEMO K63 (K63-Ub) and Met1 (Met1-Ub) were significantly increased in the 16 M-UGPase^--infected cells compared with that of the 16 M-infected cells, further confirming that the ubiquitination levels of NF-κB signaling-related proteins were regulated by the bacterial UGPase. Besides, the expression level of IκBα was decreased, but the level of p-P65 was significantly increased in the 16 M-UGPase^--infected cells compared with that of the 16 M- and mock-infected cells, demonstrating that B. melitensis UGPase can significantly inhibit the degradation of IκBα and the phosphorylation of p65, and thus suppressing the NF-κB pathway.

CONCLUSIONS

The results of this study showed that Brucella melitensis UGPase inhibits the activation of NF-κB by modulating the ubiquitination of NEMO, which will provide a new scientific basis for the study of immune mechanisms induced by Brucella.

Study of cellular heterogeneity and differential dynamics of autophagy in human embryonic kidney development by single-cell RNA sequencing

Background

Autophagy is believed to participate in embryonic development, but whether the expression of autophagy-associated genes undergoes changes during the development of human embryonic kidneys remains unknown.

Methods

In this work, we identified 36,151 human renal cells from embryonic kidneys of 9–18 gestational weeks in 16 major clusters by single-cell RNA sequencing (scRNA-seq), and detected 1350 autophagy-related genes in all fetal renal cells. The abundance of each cell cluster in Wilms tumor samples from scRNA-seq and GDC TARGET WT datasets was detected by CIBERSORTx. R package Monocle 3 was used to determine differentiation trajectories. Cyclone tool of R package scran was applied to calculate the cell cycle scores. R package SCENIC was used to investigate the transcriptional regulons. The FindMarkers tool from Seurat was used to calculate DEGs. GSVA was used to perform gene set enrichment analyses. CellphoneDB was utilized to analyze intercellular communication.

Results

It was found that cells in the 13th gestational week showed the lowest transcriptional level in each cluster in all stages. Nephron progenitors could be divided into four subgroups with diverse levels of autophagy corresponding to different SIX2 expressions. SSBpod (podocyte precursors) could differentiate into four types of podocytes (Pod), and autophagy-related regulation was involved in this process. Pseudotime analysis showed that interstitial progenitor cells (IPCs) potentially possessed two primitive directions of differentiation to interstitial cells with different expressions of autophagy. It was found that NPCs, pretubular aggregates and interstitial cell clusters had high abundance in Wilms tumor as compared with para-tumor samples with active intercellular communication.

Conclusions

All these findings suggest that autophagy may be involved in the development and cellular heterogeneity of early human fetal kidneys. In addition, part of Wilms tumor cancer cells possess the characteristics of some fetal renal cell clusters.

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s12935-021-02154-w.

Aortic Aneurysms, Chronic Kidney Disease and Metalloproteinases

Metalloproteinases (MPs) are proteolytic enzymes involved in extracellular matrix deposition, regulation of cellular signals of inflammation, proliferation, and apoptosis. Metalloproteinases are classified into three families: Matrix-MPs (MMPs), A-Disintegrin-and-Metalloprotease (ADAMs), and the A-Disintegrin-and-Metalloproteinase-with-Thrombospondin-1-like-Domains (ADAMTS). Previous studies showed that MPs are involved in the development of aortic aneurysms (AA) and, concomitantly, in the onset of chronic kidney disease (CKD). CKD has been, per se, associated with an increased risk for AA. The aim of this review is to examine the pathways that may associate MPs with CKD and AA. Several MMPs, such as MMP-2, -8, -9, and TIMP-1 have been shown to damage the AA wall and to have a toxic effect on renal tubular cells, leading to fibrosis. Similarly, ADAM10 and 17 have been shown to degrade collagen in the AA wall and to worsen kidney function via pro-inflammatory stimuli, the impairment of the Renin-Angiotensin-Aldosterone System, and the degradation of structural proteins. Moreover, MMP-2 and -9 inhibitors reduced aneurysm growth and albuminuria in experimental and human studies. It would be important, in the future, to expand research on MPs from both a prognostic, namely, to refine risk stratification in CKD patients, and a predictive perspective, likely to improve prognosis in response to targeted treatments.

The Role of Cell Adhesion Molecule 1 (CADM1) in Cutaneous Malignancies

Cell adhesion ability is one of the components to establish cell organization and shows a great contribution to human body construction consisting of various types of cells mixture to orchestrate tissue specific function. The cell adhesion molecule 1 (CADM1) is a molecule of cell adhesion with multiple functions and has been identified as a tumor suppressor gene. CADM1 has multifunctions on the pathogenesis of malignancies, and other normal cells such as immune cells. However, little is known about the function of CADM1 on cutaneous cells and cutaneous malignancies. CADM1 plays an important role in connecting cells with each other, contacting cells to deliver their signal, and acting as a scaffolding molecule for other immune cells to develop their immune responses. A limited number of studies reveal the contribution of CADM1 on the development of cutaneous malignancies. Solid cutaneous malignancies, such as cutaneous squamous cell carcinoma and malignant melanoma, reduce their CADM1 expression to promote the invasion and metastasis of the tumor. On the contrary to these cutaneous solid tumors except for Merkel cell carcinoma, cutaneous lymphomas, such as adult-T cell leukemia/lymphoma, mycosis fungoides, and Sézary syndrome, increase their CADM1 expression for the development of tumor environment. Based on the role of CADM1 in the etiology of tumor development, the theory of CADM1 contribution will desirably be applied to skin tumors according to other organ malignancies, however, the characteristics of skin as a multicomponent peripheral organ should be kept in mind to conclude their prognoses.

Cell Adhesion Molecule 1 Contributes to Cell Survival in Crowded Epithelial Monolayers

When epithelial cells in vivo are stimulated to proliferate, they crowd and often grow in height. These processes are likely to implicate dynamic interactions among lateral membranous proteins, such as cell adhesion molecule 1 (CADM1), an immunoglobulin superfamily member. Pulmonary epithelial cell lines that express CADM1, named NCI-H441 and RLE-6TN, were grown to become overconfluent in the polarized 2D culture system, and were examined for the expression of CADM1. Western analyses showed that the CADM1 expression levels increased gradually up to 3 times in a cell density-dependent manner. Confocal microscopic observations revealed dense immunostaining for CADM1 on the lateral membrane. In the overconfluent monolayers, CADM1 knockdown was achieved by two methods using CADM1-targeting siRNA and an anti-CADM1 neutralizing antibody. Antibody treatment experiments were also done on 6 other epithelial cell lines expressing CADM1. The CADM1 expression levels were reduced roughly by half, in association with cell height decrease by half in 3 lines. TUNEL assays revealed that the CADM1 knockdown increased the proportion of TUNEL-positive apoptotic cells approximately 10 folds. Increased expression of CADM1 appeared to contribute to cell survival in crowded epithelial monolayers.

CADM1 inhibits ovarian cancer cell proliferation and migration by potentially regulating the PI3K/Akt/mTOR pathway

Previous studies have shown that cell adhesion molecule 1 (CADM1), an immunoglobulin superfamily member, is frequently inactivated but functions as a tumor suppressor in many solid tumors. However, the characterization of CADM1 expression in ovarian cancer cells and the mechanisms of its tumor suppressor function are not fully understood. We generated ovarian cancer cell lines in which CADM1 was stably upregulated or downregulated. CADM1 expression was significantly decreased in ovarian cancer tissue and cells lines. Functionally, knockdown of CADM1 promoted the growth, migration and invasion of ovarian cancer cells. Conversely, further experimental evidence indicated that overexpression of CADM1 inhibited the migration and invasion of ovarian cancer cells potentially through inhibition of the PI3K/Akt/mTOR signaling pathway by regulating upstream regulators (LXR/RXR, IGF1, IFI44L and C4BPA) and downstream effectors (APP, EDN1, TGFBI and Rap1A). In conclusion, CADM1 inhibits ovarian cancer cell proliferation and migration by potentially regulating the PI3K/Akt/mTOR signaling pathway. CADM1 could be a potential therapeutic target for ovarian cancer.

Urinary Cell Adhesion Molecule 1 Is a Novel Biomarker That Links Tubulointerstitial Damage to Glomerular Filtration Rates in Chronic Kidney Disease

Cell adhesion molecule 1 (CADM1) is an immunoglobulin superfamily member strongly expressed on renal tubular epithelia in the urinary tract. Enzymatic cleavage of its ectodomain increases in chronic kidney disease (CKD), and is assumed to contribute to tubulointerstitial lesion formation. Because the cleaved ectodomain fragments are likely to be released into the urine, a sandwich enzyme-linked immunosorbent assay (ELISA) system for urinary CADM1 was developed using two anti-ectodomain antibodies. Urinary CADM1 concentrations in patients with CKD based on various forms of glomerulonephritis and nephropathy (n = 127) were measured. A total of 44 patients (35%) had elevated CADM1 concentrations over the normal upper limit (362 pg/mL), with a mean of 1,727 pg/mL. Renal biopsy specimens of all patients were pathologically scored for tubulointerstitial lesions using epithelial degeneration, interstitial inflammation, and fibrosis. There were no correlations between urinary CADM1 concentrations and pathological scores or any widely used renal markers, including glomerular filtration rate (GFR), but there was a weak inverse correlation between pathological scores and GFR (R² = 0.292). Notably, this correlation gradually increased in patients with increasing CADM1 concentrations, and reached a maximum R² (0.899) at a cutoff of 1,569 pg/mL. The results of this study suggest that urinary CADM1 is a useful marker indicating tubulointerstitial damage from elevated GFR levels in CKD.

Renal ADAM10 and 17: Their Physiological and Medical Meanings

A disintegrin and metalloproteinases (ADAMs) are a Zn²⁺-dependent transmembrane and secreted metalloprotease superfamily, so-called “molecular scissors,” and they consist of an N-terminal signal sequence, a prodomain, zinc-binding metalloprotease domain, disintegrin domain, cysteine-rich domain, transmembrane domain and cytoplasmic tail. ADAMs perform proteolytic processing of the ectodomains of diverse transmembrane molecules into bioactive mediators. This review summarizes on their most well-known members, ADAM10 and 17, focusing on the kidneys. ADAM10 is expressed in renal tubular cells and affects the expression of specific brush border genes, and its activation is involved in some renal diseases. ADAM17 is weakly expressed in normal kidneys, but its expression is markedly induced in the tubules, capillaries, glomeruli, and mesangium, and it is involved in interstitial fibrosis and tubular atrophy. So far, the various substrates have been identified in the kidneys. Shedding fragments become released ligands, such as Notch and EGFR ligands, and act as the chemoattractant factors including CXCL16. Their ectodomain shedding is closely correlated with pathological factors, which include inflammation, interstitial fibrosis, and renal injury. Also, the substrates of both ADAMs contain the molecules that play important roles at the plasma membrane, such as meaprin, E-cadherin, Klotho, and CADM1. By being released into urine, the shedding products could be useful for biomarkers of renal diseases, but ADAM10 and 17 per se are also notable as biomarkers. Furthermore, ADAM10 and/or 17 inhibitions based on various strategies such as small molecules, antibodies, and their recombinant prodomains are valuable, because they potentially protect renal tissues and promote renal regeneration. Although temporal and spatial regulations of inhibitors are problems to be solved, their inhibitors could be useful for renal diseases.