Thrombospondin Type-1 Domain-containing 7A Research Articles

Clinicopathological characteristics of neural epidermal growth factor-like 1 protein-associated membranous glomerulonephritis.

Neural epidermal growth factor-like 1 protein (NELL1) is the second most common target antigen in membranous glomerulonephritis (MGN). However, data regarding the clinicopathological characteristics of NELL1-associated MGN are limited owing to its low prevalence. This study examined the prevalence and clinicopathological characteristics of NELL1-associated MGN in a Japanese cohort. Additionally, we compared the clinicopathological features of NELL1-positive MGN, phospholipase A2 receptor 1 (PLA2R1)-positive MGN, and MGN negative for all three antigens (NELL1, PLA2R1, and thrombospondin type-1 domain-containing 7A). Among 257 consecutive patients pathologically diagnosed with MGN at two centers in Japan, 24 (9.3%) were immunohistochemically positive for NELL1. Clinically, patients with NELL1-positive MGN were significantly older (p < 0.001) and had a higher frequency of bucillamine use (vs PLA2R1-positive MGN, p < 0.01). Histologically, NELL1-positive MGN exhibited significantly lower detection of spikes and crater formation (p < 0.001), higher prevalence of segmental spike distribution (vs PLA2R1-positive MGN: p < 0.001), and higher prevalence of stage I cases on electron microscopy (p < 0.01). There were no significant differences in the prognoses among the three groups. The characteristic histological feature of segmental distribution in NELL1-positive MGN may be related to bucillamine use and the early phase of the disease. Further investigations with larger numbers of patients may offer further insight into the prognosis of patients with NELL1-positive MGN.

Diagnosis and Treatment of Membranous Nephropathy in Integrative Medicine

Membranous nephropathy (MN) is a common glomerular disease. The related pathological changes are primarily characterized by the deposition of immune complexes beneath the epithelial cells of the glomerular basement membrane, accompanied by diffuse thickening of the basement membrane. Its etiology and pathogenesis are not fully understood yet; however, they are associated with genetics, infections, tumors, drugs, heavy metals poisoning, environmental pollution, and the loss of immune tolerance. Over 10 target antigens, including the phospholipase A2 receptor (PLA2R) and thrombospondin type 1 domain containing 7A (THSD7A), associated with MN have been identified, each having different clinical implications. Clinical manifestations of MN patients mainly include proteinuria and nephrotic syndrome, with a propensity to form thrombi. Its diagnostic accuracy can be enhanced by combining clinical manifestations, serum antibody testing, and renal biopsy. Proteinuria, estimated glomerular filtration rate (eGFR), and PLA2R antibody levels are vital for the prognostic risk stratification of MN. Low-risk patients primarily undergo non-immunosuppressive treatment (angiotensin-converting enzyme inhibitor [ACEI]/angiotensin II receptor blocker [ARB], sodium-glucose cotransporter 2 inhibitor [SGLT2i], anticoagulants, and traditional Chinese medicine [TCM] treatments), while high-risk patients need to consider using steroids and immunosuppressants, such as cyclophosphamide (CTX), calcineurin inhibitors (CNIs), and anti-cluster of differentiation 20 (anti-CD20) monoclonal antibodies. TCM holds that MN is the imbalance of Fei (lung), Pi (spleen), and Shen (kidney) function, leading to the generation of Neixie such as Shi, Re, Du, and Yu. This disease is difficult to heal because of Shire and Yu. The treatment is based on the use of Jianpi Bushen, simultaneously emphasizing the use of drugs for Qingre Qushi Huoxue. Dialectical use of TCM can obviously improve the clinical response rate and alleviate symptoms such as edema and fatigue by increasing the serum albumin level more rapidly while introducing fewer adverse reactions. Combined with Western medicine, TCM can also reduce toxicity and increase efficiency. This article systematically reviews the etiology, podocyte antigens, clinical manifestations, diagnostic approaches, risk assessment, and integrative medicine therapeutic strategies for MN, aiming to deepen the understanding of MN and guide clinical practice.

Therapeutic targets in membranous nephropathy: plasma cells and complement.

Membranous nephropathy (MN) is an antibody-mediated autoimmune disease and the most common cause of nephrotic syndrome in adults. The discovery of phospholipase A2 receptor 1 (PLA2R1) as the first target antigen in patients with MN 15years ago has led to a paradigm shift in the pathobiological understanding of this disease. Autoantibodies against PLA2R1 as well as thrombospondin type-1 domain-containing 7A, the second identified antigen in adults, were shown to be disease-causing and act through local activation of the complement system, primarily via the classical and lectin pathways. These findings indicate that both plasma cells, the main source of antibodies and autoantibodies, as well as the complement system, the main pathogenic effector mechanism in MN, are rational and pathogenesis-based treatment targets in MN. This review summarizes pathomechanistic and clinical evidence for and against plasma cell- and complement-targeted treatments in MN.

THSD7A-associated membranous nephropathy involves both complement-mediated and autonomous podocyte injury.

Membranous nephropathy (MN) continues to be a leading cause of nephrotic syndrome in non-diabetic adults. As a unique subtype in the serology-based classification of MN, thrombospondin type 1 domain containing 7A (THSD7A)-associated MN has attracted increasing interest, because, unlike other autoantigens, THSD7A is also expressed in preclinical species, facilitating the study of its role in MN. A heterologous mouse model of THSD7A-associated MN was previously established using a proprietary in-house antibody that was unfortunately not available to the research community. Here, we developed a mouse model of THSD7A-associated MN by administering a commercially available antibody targeting the most N-terminal part of THSD7A. Our model was characterized by heavy proteinuria and pathological features of human MN without sex differences. Complement depletion with cobra venom factor only partially attenuated proteinuria and glomerular injury in this model, entailing that complement-independent pathomechanisms also contribute. Consistently, in vitro in primary podocytes, exposure to the anti-THSD7A antibody caused evident podocytopathic changes, including disruption of actin cytoskeleton integrity, podocyte hypermobility, oxidative stress, and apoptotic cell death. These signs of podocytopathy were preserved, albeit to a lesser extent, after complement inactivation, indicating autonomous podocyte injury. Furthermore, as the first FDA-approved treatment for primary MN, adrenocorticotropic hormone therapy with repository corticotropin injection (Purified Cortrophin Gel®) appeared to be beneficial and significantly attenuated proteinuria and glomerular injury, suggesting that this model may be useful for developing novel treatments or understanding the pathogenesis of MN. Collectively, our model, based on the use of a commercially available anti-THSD7A antibody, will be an important tool for MN research.

The Prevalence, Characteristics, and Putative Mechanisms of Dual Antigen-Positive Membranous Nephropathy: The Underestimated Condition.

Following the discovery of podocyte phospholipase A2 receptor and thrombospondin type-1 domain-containing 7A, various potential target antigens for membranous nephropathy (MN) have been reported one after another. MN target antigens have now been identified in a significant proportion of patients, and a new classification framework classifies patients with MN based on the detected antigen and associated disease phenotype. A serology-based approach that does not require a histological diagnosis for patients suspected of having MN has also been proposed. However, there have been cases in which dual positivity for MN antigens and/or corresponding antibodies has been shown. Importantly, some of them showed a transition of the affected patient's immune responses to MN antigens, suggesting that serological diagnosis changes depending on the timing of the analysis. In this review, we provide detailed information on these cases and present an overview of our recent understanding of their putative mechanisms involved in these cases. Greater awareness is required to adequately recognize and develop appropriate therapeutic strategies for this condition.

Prevalence and prognosis of malignancy in THSD7A-associated membranous nephropathy: a systematic literature review and clinical case study

Background This study aims to investigate the incidence and prognosis of malignancy in individuals with thrombospondin type-1 domain-containing 7A (THSD7A)-associated membranous nephropathy (MN). Methods First, we performed a systematic literature review of prevalence of malignancy in THSD7A-associated MN. Then, we conducted a retrospective analysis of 454 patients diagnosed with MN through renal biopsy at our hospital between January 2016 and December 2020. We assessed the presence of serum anti-THSD7A antibodies and performed immunohistochemical staining of renal tissue for THSD7A. Subsequently, we followed patients with THSD7A-associated MN for a minimum of 3–5 years, collecting their clinical, pathological characteristics, and prognosis. Additionally, we conducted a literature review on patients with THSD7A-associated MN in conjunction with malignancy. Results We identified a total of nine articles containing comprehensive data on THSD7A-associated MN and malignancy. Among 235 patients with THSD7A-positive MN, 36 individuals had concurrent malignancies, resulting in a malignancy prevalence of 13.3% (95% CI: 8.9–17.7%). In our center, we followed up with 15 patients diagnosed with THSD7A-associated MN and observed three cases of concomitant tumors: two cases of lung adenocarcinoma and one case of small cell lung cancer with multiple metastases. The prevalence of malignancy in our cohort was 20%. Notably, we detected positive THSD7A staining in both renal and lung cancer tissues in one patient with small cell lung cancer. Conclusions Patients with THSD7A-associated MN should undergo vigilant follow-up assessments, with a particular focus on actively seeking potential tumorigenic lesions to prevent misdiagnosis or oversight.

Down-Regulation of miRNA-1303 Promotes the Angiogenesis of HUVECs via Targeting THSD7A.

Angiogenesis promotes neurological recovery after acute ischemic stroke (AIS), and microRNAs play crucial roles in cerebral angiogenesis. This study found that Homo sapiens-microRNA-1303(miR-1303) was reduced in blood specimens of AIS patients and human umbilical vein endothelial cells after suffering from oxygen-glucose deprivation/reperfusion. The experiment detected the effect of miR-1303 on angiogenesis by wound healing assay, tube formation assay, and transwell assay. Down-regulation of miRNA-1303 promotes angiogenesis in vitro experiments, while miR-1303 over-expression reverses this effect. Based on bioinformatics analyses and dual-luciferase reporter assay, the thrombospondin type 1 domain containing 7A (THSD7A) was investigated and further validated as the downstream gene of miR-1303. Furthermore, the knockdown of miR-1303 decreased the protein translation and mRNA transcript levels of THSD7A. Our results reveal a novel miR-1303/THSD7A pathway for angiogenesis and further imply that miR-1303 can be a promising biomarker and therapeutic target for AIS.

#6502 ETIOLOGICAL SPECTRUM OF MEMBRANOUS NEPHROPATHY

Abstract Background and Aims Primary MN includes forms of MN in which there is a humoral autoimmune response to a normal podocyte antigen in the absence of secondary features or etiologies of disease. Antigens implicated in primary MN include PLA2R, thrombospondin type-1 domain-containing 7A (THSD7A), neural epidermal growth factor-like 1 (NELL1), semaphorin 3B (Sema3B), the serine protease high-temperature requirement A1 (HTRA1), protocadherin 7 (PCDH7), and others. PLA2R associated MN is most common MN among primary MN. Nowadays, a significant number of newer antigens implicating MN are being discovered. Research is ongoing for a better understanding of the role of these antigens in pathophysiology, and targeted therapeutic implications in future if possible. We aim to analyze the etiological spectrum associated with different antigens in patients with Membranous Nephropathy. We assessed the renal tissue staining of autoantigens PLA2R, THSD7A, and NELL-1 in patients with biopsy-proven Membranous Nephropathy. Method This was a single center ambispective observational study. The study was performed up till September 2022 for prospective data, and retrospective data from January 2018 to March 2021 was retrieved from the medical records department of the institute. The study included patients with biopsy-proven Membranous Nephropathy (Primary and secondary). The primary outcome was to study the etiological spectrum of Membranous Nephropathy. Results A total of 90 patients were included in the study of membranous nephropathy over the period of 4 years. 72 cases had primary MN whereas 18 cases had secondary MN. The mean age was 42.01 ± 14.6 years. Among 18 cases of Secondary MN, the majority of the cases were of lupus nephritis 14 (78%), while other etiologies of secondary MN were malignancy related (11%), rheumatoid arthritis (5.5%) and HCV (5.5%). PLA2R renal tissue positivity was found in 44 (61.1%) cases of primary MN, whereas in 4 (22.2%) cases of Secondary MN. The THSD7A was found in 4 (5.6%) cases of primary MN. One patient of MN was dual PLA2R and NELL1 positive. Two cases of MN were dual PLA2R and THSD7A positive. Renal tissue staining for NELL-1 was found in 8 (11.1%) cases of primary MN whereas it was found in 1 (5.6%) case of secondary MN. In terms of clinical presentation, proteinuria is the most common clinical finding present in nearly all the patients (80%). Most of the cases with nephrotic syndrome (60%) belonged to primary MN. Conclusion PLA2R is the most common etiology of Primary membranous nephropathy. None of the antigens was exclusive to primary membranous nephropathy.

#4851 MOLECULAR FEATURES OF CIRCULATORY B CELLS AND RENAL CELLS AT THE SINGLE-CELL LEVEL IN AUTOANTIBODY-NEGATIVE PRIMARY MEMBRANOUS NEPHROPATHY PATIENTS

Abstract Background and Aims Primary membranous nephropathy (PMN) is an organ-specific autoimmune disease that is the most common cause of idiopathic nephrotic syndrome in adults. Furthermore, the incidence of PMN is increasing, especially in young adults and children. The landmark discovery of nephritogenic autoantibodies against podocyte antigens such as M-type phospholipase A2 receptor (PLA2R) and thrombospondin type-1 domain-containing protein 7A (THSD7A) has provided a paradigm shift in diagnosis and treatment of PMN. However, there are still few patients with negative serum and renal tissue autoantibodies. This study aims to explore the molecular features of antibody-negative PMN. Method We sorted CD19+ cells from the peripheral blood of a pediatric patient with seven nephritogenic autoantibodies-negative PMN (NEG) by flow cytometry and performed single-cell transcriptome sequencing (scRNA-seq) and single-cell B cell receptor sequencing (scBCR-seq). Meanwhile, scRNA-seq was performed on renal biopsy tissues from the same patient. In addition, we included the scRNA-seq data of renal from anti-PLA2R antibody positive patients (POS) and healthy controls (CTRL), and the scBCR-seq data of B cell from CTRL for integrative analysis. Results The NEG patient showed typical nephrotic syndrome and was diagnosed as stage Ⅲ membranous nephropathy by renal biopsy. There was no evidence of anti-PLA2R or anti-THSD7A antibodies in peripheral blood and seven nephritogenic autoantibodies such as anti-PLA2R antibodies in renal tissue. After excluding secondary factors, the patient was diagnosed with PMN. Through scRNA-seq of CD19+ cells, we found that the number, characteristic gene, function and clonotype of naÏve B cells and memory B cells in NEG were significantly changed. Expanded CD38+ naÏve B cells in NEG had the molecular characteristics of CD19+CD24+CD27-CD38+, defined as transitional B cells. This group of cells had distinct function features of cell activation, and its up-regulated genes were involved in multiple aspects of the BCR signaling pathway. Pseudotime trajectory analysis suggested CD38+ naÏve B cells were highly enriched in the beginning of B cell differentiation. There was a preference in the use of VJ gene segments of B cells between NEG and CTRL, especially an increase of the IGHV3-23 and IGLV2-14 in NEG. The stronger pairing frequencies, IGLV2-14/IGLJ3 and IGKV2D-29/IGKJ2, were indicated in NEG. We identified 14 distinct kidney cell types by marker genes. Through re-clustering of glomerular parietal epithelial cells (PECs), the patients were clearly distinct from their control counterparts, indicating a major shift in gene expression for this cell type. PECs in NEG showed significant up-regulation of cellular communication network factor-related genes (CCN1, CCN2), phospholipase A and acyltransferase-related genes (PLAAT4, PLAAT3), and septin protein-related genes (SEPTIN2, SEPTIN7), accompanied by significant down-regulation of podocyte-related genes. In addition, there are clearly distinct cellular functions and pseudotime trajectory in PECs from NEG and POS, and genes such as CCN2, PLAAT4, SEPTIN2 might drive the special trajectory of PECs in NEG. For the podocytes, the genes related with extracellular matrix and cell adhesion were significantly enhanced in NEG, which consistented with the functional enrichment analysis of the differentially expressed genes and gene set-based scores. We calculated the gene set-based scores including genes encoding lumen-to-blood sodium transporters. Results indicated the enhanced expression of sodium transporters in distal nephrons of MN patients. More surprisingly, a group of proximal tubule epithelial cells showed significantly higher expression levels of sodium transporters. Among them, the expression of SLC5A12 encoding SMCT2 increased significantly. Conclusion We have systematic revealed the cell-type specific molecular features of PMN patients from circulation to renal tissue. Our research provides valuable evidence for the molecular diagnosis of PMN in children and insights into pathogenic mechanism of classical nephritogenic autoantibody-negative PMN.

Heterogeneity of Target Antigens in Sarcoidosis-Associated Membranous Nephropathy

Membranous nephropathy (MN) is the most common glomerular disease associated with sarcoidosis. The target antigen M-type phospholipase A2 receptor 1 (PLA2R) has been identified in a subset of sarcoidosis-associated MN. The target antigen is not known in the remaining sarcoidosis-associated MN. Data of patients with history of sarcoidosis and biopsy-proven MN were retrieved and analyzed. Mass spectrometry (MS/MS) was performed on all kidney biopsies of sarcoidosis-associated MN to detect the target antigens. Immunohistochemistry (IHC) studies were performed to confirm and localize the target antigens along the glomerular basement membrane (GBM). Eighteen patients with history of sarcoidosis and biopsy-proven MN were identified, of whom 3 were known to be PLA2R-negative, and in the remaining patients the target antigen was unknown. Thirteen (72%) patients were males; the median age at MN diagnosis was 54.5 years. The median proteinuria at presentation was proteinuria 9.8 g/24 h. Eight patients (44.4%) had concurrent sarcoidosis. Using MS/MS, we detected PLA2R and neural epidermal growth factor-like-1 protein (NELL1) in 7 (46.6%) and 4 (22.2%) patients, respectively. In addition, 1 case each (5.5%) was positive for thrombospondin type 1 domain-containing 7A (THSD7A), protocadherin-7 (PCDH7), and putative antigen Serpin B12. No known target antigen was detected in the remaining 4 patients (22.2%). Patients with sarcoidosis and MN exhibit heterogeneous target antigens. We identified, along with PLA2R, the presence of previously unreported antigens, including NELL1, PCDH7, and THSD7A. The incidence of the target antigens in sarcoidosis appears to mirror the overall incidence of target antigens in MN. MN in sarcoidosis may be the result of a heightened immune response and is not associated with a single target antigen.

Clinical Significance of Thrombospondin Type 1 Domain-Containing 7A and Neural Epidermal Growth Factor-Like 1 Protein in M-Type Phospholipase A2 Receptor-Negative Membranous Nephropathy

Objective To investigate the clinical significance of thrombospondin type 1 domain-containing 7A (THSD7A) and neural epidermal growth factor-like 1 protein (NELL1) in phospholipase A2 receptor (PLA2R)-negative membranous nephropathy (MN). Methods A total of 116 PLA2R-negative MN patients treated in Hangzhou TCM Hospital Affiliated to Zhejiang Chinese Medical University from 2014 to 2021 were enrolled in this study.Immunohistochemistry was employed to detect THSD7A and NELL1 in the renal tissue.The pathological characteristics,treatment,and prognosis were compared between positive and negative groups. Results The 116 PLA2R-negative MN patients included 23 THSD7A-positive patients and 9 NELL1-positive patients.One patient was tested positive for both proteins.The THSD7A-positive group showed higher positive rate of IgG4 (P=0.010),more obvious glomerular basement membrane (GBM) thickening (P=0.034),and higher proportion of stage Ⅱ MN and lower proportion of stage I MN (P=0.002) than the THSD7A-negative group.The NELL1-positive group had lower positive rates of C1q and IgG2 (P=0.029,P=0.001),less obvious GBM thickening (P<0.001),more extensive inflammatory cell infiltration (P=0.033),lower proportion of deposits on multi-locations (P=0.001),and lower proportion of atypical MN (P=0.010) than the NELL1-negative group.One patient with THSD7A-positive MN was diagnosed with colon cancer,while none of the NELL1-positive patients had malignancy.Survival analysis suggested that THSD7A-positive MN had worse composite remission (either complete remission or partial remission) of nephrotic syndrome than the negative group (P=0.016),whereas NELL1-positive MN exhibited better composite remission of nephrotic syndrome than the negative group (P=0.015).The MN patients only positive for NELL1 showed better composite remission of nephrotic syndrome than the MN patients only positive for THSD7A (P<0.001). Conclusions THSD7A- and NELL1-positive MN is more likely to be primary MN,and there is no significant malignancy indication.However,it might have a predictive value for the prognosis of MN.

A Genetic Risk Score Distinguishes Different Types of Autoantibody-Mediated Membranous Nephropathy

Introduction: Membranous nephropathy (MN) is the leading cause of nephrotic syndrome in adults and is characterized by detectable autoantibodies against glomerular antigens, most commonly phospholipase A2 receptor 1 (PLA2R1) and thrombospondin type-1 domain containing 7A (THSD7A). In Europeans, genetic variation in at least five loci, PLA2R1, HLA-DRB1, HLA-DQA1, IRF4, and NFKB1, affects the risk of disease. Here, we investigated the genetic risk differences between different autoantibody states. Methods: 1,409 MN individuals were genotyped genome-wide with a dense SNV array. The genetic risk score (GRS) was calculated utilizing the previously identified European MN loci, and results were compared with 4,929 healthy controls and 422 individuals with steroid-sensitive nephrotic syndrome. Results: GRS was calculated in the 759 MN individuals in whom antibody status was known. The GRS for MN was elevated in the anti-PLA2R1 antibody-positive (N = 372) compared with both the unaffected control (N = 4,929) and anti-THSD7A-positive (N = 31) groups (p < 0.0001 for both comparisons), suggesting that this GRS reflects anti-PLA2R1 MN. Among PLA2R1-positive patients, GRS was inversely correlated with age of disease onset (p = 0.009). Further, the GRS in the dual antibody-negative group (N = 355) was intermediate between controls and the PLA2R1-positive group (p < 0.0001). Conclusion: We demonstrate that the genetic risk factors for PLA2R1- and THSD7A-antibody-associated MN are different. A higher GRS is associated with younger age of onset of disease. Further, a proportion of antibody-negative MN cases have an elevated GRS similar to PLA2R1-positive disease. This suggests that in some individuals with negative serology the disease is driven by autoimmunity against PLA2R1.

Segmental Membranous Glomerulopathy in Adults

Introduction: The clinicopathological features of segmental membranous glomerulopathy (SMGN) have not been well characterized. The aim of this study was to investigate the prevalence and clinicopathological features of SMGN in adults. Methods: Adult patients with biopsy-confirmed SMGN in the native kidney at our center between January 2017 to September 2020 were identified. The clinicopathological features of SMGN were collected. The glomerular deposition of IgG subclasses, M-type phospholipase A2 receptor 1 (PLA2R), thrombospondin type 1 domain-containing 7A (THSD7A), and neural epidermal growth factor-like 1 protein (NELL1) were tested. Clinical and pathologic features were comparable between NELL1-positive and NELL1-negative SMGN. Results: A total of 167 patients with biopsy-proven SMGN were enrolled. During the same period, 32,640 (33.0%) out of 98,939 renal biopsies were diagnosed with membranous nephropathy (MN) in adults. SMGN accounted for 0.17% of total kidney biopsies and 0.51% of MN in adults. One hundred and fifty (89.8%) cases were isolated SMGN, and 17 (10.2%) cases were complicated with other kidney disease. Clinically, the median age of isolated SMGN patients was 41.5 years, with female (74%) predominance, and 33.1% had full nephrotic syndrome. Pathologically, IgG1 was the dominant subclass (92.5%), followed by IgG4 (45.0%). PLA2R and THSD7A staining were done in 142 and 136 isolated SMGN cases, respectively, in which, all the cases showed negative. NELL1 staining was done in 135 isolated SMGN cases; 58 cases (43.0%) showed positive. Fifty-eight patients (41.1%) had diffuse (≥90%) foot process effacement, and 119 patients (83.8%) had either stage I (38.0%) or stage II (45.8%) membranous alterations in patients with SMGN. Most patients with NELL1-positive SMGN were female. Patients with NELL1-positive SMGN were more likely with lower prevalence of full nephrotic syndrome than NELL1-negative SMGN. Conclusions: SMGN is a relatively rare pathological type. Majority of patients with isolated SMGN were female, with a median age of 41.5 years, 33.1% had full nephrotic syndrome, absence of PLA2R and THSD7A, 43.0% with NELL1-positive, and mainly stage I or II MN (83.8%). NELL1 is the major target antigen of SMGN in adults.

Disease-Specific Treatment For Primary Membranous Nephropathy: The Role of Monoclonal Antibodies

Primary Membranous Nephropathy is an autoimmune disease caused by the deposition of Immunoglobulin G and complement components on the subepithelial layer of the glomerular capillary wall. It affects 5-10 patients per million population and is the second cause of nephrotic syndrome in adults after diabetic kidney disease. For decades steroids and non-specific immunosuppressive medications have been advocated as a therapeutic option for patients with membranous nephropathy at increased risk of kidney failure because of persistent nephrotic syndrome. These medications, however, have major and potentially fatal adverse effects that offset their potential benefits and should be abandoned. The discovery of nephritogenic autoantibodies against podocyte M-type phospholipase A2 receptor (PLA2R) and thrombospondin type-1 domain-containing protein 7A (THSD7A) antigens provided a clear pathophysiological rationale for interventions specifically targeting B cell lineages to prevent antibody production and subepithelial deposition. The first-in-class anti-CD20 monoclonal antibody rituximab is safe and achieves remission in approximately two-thirds of patients with nephrotic membranous nephropathy. In PLA2R-related disease, remission is invariably preceded by depletion of anti PLA2R autoantibodies and relapse by their re-emergence into the circulation. Because of its superior risk/benefit profile as compared to non-specific immunosuppressive therapy, rituximab is now first-line therapy for patients with membranous nephropathy at risk of kidney failure. Novel monoclonal antibodies targeting CD20 cells (such as ofatumumab and obinutuzumab) and their differentiation (belimumab) or targeting long-living antibody producing CD38 memory cells (daratumumab, felzartamab) along with proteasome inhibitors such as bortezomib are being evaluated for the treatment of nephrotic patients with membranous nephropathy who are resistant or intolerant to rituximab. Complement inhibitor therapy might serve to stop the glomerular inflammatory process until the benefits of these medications become effective. Thus, major advances in the understanding of the mechanisms of membranous nephropathy have led to novel treatment perspectives. The integrated evaluation of serum autoantibody titer and proteinuria, together with serum albumin levels in patients with overt nephrotic syndrome, could guide diagnosis of membranous nephropathy and individually tailored treatment protocols. The introduction of monoclonal antibodies targeting disease-specific mechanisms will pave the way for a novel therapeutic paradigm based on the principle of precision medicine and personalized therapy.

Determination of Anti-Phospholipase A2 and Anti-Thrombospondin Type 1 Domain-Containing Protein 7A in Latin Patients with Membranous Nephropathy

Primary membranous nephropathy (MN) is caused by antibodies against podocyte antigens, especially the type M receptor of phospholipase A2 (PLA2R) and thrombospondin type-1 domain containing 7 A (THSD7A). This study's aim was the determination of anti-PLA2R, anti-THSD7A serum antibodies, and anti-PLA2R renal tissue staining prevalence in a Latin population with MN, as well as evaluating their role as biomarkers for disease activity. The performance of the two anti-PLA2R serum diagnostic methods-ELISA and indirect immunofluorescence (IFI)-was evaluated for the diagnosis of MN. Fifty-nine patients, including 29 with MN, 18 with lupus membranous nephropathy (LMN) and 12 with focal and segmental glomerulosclerosis (FSGS), were evaluated for serum antibodies. Renal biopsies were also evaluated for the presence of anti-PLA2R staining. Twenty-one patients with MN were followed for 1 year. Patients with LMN and FSGS were negative for both antibodies. All 29 MN patients were negative for anti-THSD7A; 16 MN patients were positive for anti-PLA2R by ELISA and/or IFI, and 3 MN patients were positive for anti-PLA2R only by IFI. Thus, the anti-PLA2R ELISA test demonstrated 45% sensitivity and 97% specificity, while the IFI test showed, respectively, 55% and 100% in our MN patients. Among the 28 MN renal biopsies, 20 presented anti-PLA2R positive staining, corresponding to a 72% sensitivity. Positive correlations were observed between the anti-PLA2R ELISA titer and proteinuria. In conclusion, determination of anti-PLA2R antibodies in the MN Latin population showed similar rates to those reported for other populations. The anti-PLA2R serum levels correlated with MN disease activity.

Membranous nephropathy: Clearer pathology and mechanisms identify potential strategies for treatment.

Primary membranous nephropathy (PMN) is one of the common causes of adult-onset nephrotic syndrome and is characterized by autoantibodies against podocyte antigens causing in situ immune complex deposition. Much of our understanding of the disease mechanisms underpinning this kidney-limited autoimmune disease originally came from studies of Heymann nephritis, a rat model of PMN, where autoantibodies against megalin produced a similar disease phenotype though megalin is not implicated in human disease. In PMN, the major target antigen was identified to be M-type phospholipase A2 receptor 1 (PLA2R) in 2009. Further utilization of mass spectrometry on immunoprecipitated glomerular extracts and laser micro dissected glomeruli has allowed the rapid discovery of other antigens (thrombospondin type-1 domain-containing protein 7A, neural epidermal growth factor-like 1 protein, semaphorin 3B, protocadherin 7, high temperature requirement A serine peptidase 1, netrin G1) targeted by autoantibodies in PMN. Despite these major advances in our understanding of the pathophysiology of PMN, treatments remain non-specific, often ineffective, or toxic. In this review, we summarize our current understanding of the immune mechanisms driving PMN from animal models and clinical studies, and the implications on the development of future targeted therapeutic strategies.

The Efficacy of Cyclophosphamide Combined with Prednisone in Membranous Nephropathy Patients with Different Cytochrome P450 2B6 Gene Polymorphisms and Analysis of Factors Influencing the Efficacy.

ObjectiveTo investigate the efficacy of cyclophosphamide combined with prednisone in membranous nephropathy (MN) patients with different cytochrome P450 (CYP) 2B6 gene polymorphisms and explore the factors influencing the efficacy.MethodsWe performed a prospective and interventional study including 153 outpatients diagnosed with membranous nephropathy from April 2020 to June 2020 in the Bayannur Hospital. Based on the results of CYP2B6 gene polymorphisms, patients were divided into CYP2B6*4 group (785A>G) with 93 cases and CYP2B6*5 group (1459C>T) with 60 cases, and all patients were treated with cyclophosphamide and prednisone. The efficacy of the two groups was compared, and the serum levels of antibody against thrombospondin type-1 domain-containing 7A (THSD7A-Ab), 8-hydroxy-2’-deoxyguanosine (8-OHdG) and antibody against the M-type phospholipase A2 receptor (PLA2R-Ab) determined by the enzyme-linked immunosorbent method were analyzed in the two groups before and after treatment.ResultsAfter the treatment with cyclophosphamide and prednisone, serum levels of THSD7A-Ab, 8-OHdG, and PLA2R-Ab were higher in the CYP2B6*4 group than those in the CYP2B6*5 group (All three P<0.001). The univariate Logistic regression analysis showed that CYP2B6*4 (OR = 1.727, 95% CI: 1.028–2.654. P=0.012), CYP2B6*5 (OR = 1.802, 95% CI: 1.179–2.752. P=0.031), THSD7A-Ab (OR = 1.832, 95% CI: 0.871–2.348. P=0.023), 8-OHdG (OR = 1.661, 95% CI: 1.123–2.231. P=0.009), PLA2R-Ab (OR = 1.649, 95% CI: 1.083–2.761. P=0.017) were independent influencing factors on the efficacy of MN. The multivariate Logistic regression analysis showed that CYP2B6*4 (OR = 2.009, 95% CI: 1.327–2.703. P<0.001), CYP2B6*5 (OR = 3.009, 95% CI: 1.467–5.231. P=0.005), THSD7A-Ab (OR = 1.396, 95% CI: 1.002–1.897. P=0.019), 8-OHdG (OR = 0.704, 95% CI: 0.591–0.742. P<0.001), PLA2R-Ab (OR = 2.761, 95% CI: 1.231–3.918. P=0.017) were independent factors influencing the efficacy of cyclophosphamide and prednisone on MN.ConclusionCyclophosphamide combined with prednisone was effective in treating MN with different CYP2B6 gene polymorphisms. CYP2B6*4, CYP2B6*5, and serum levels of THSD7A-Ab, 8-OHdG, and PLA2R-Ab were independent influencing factors on the outcome of MN.

Membranous nephropathy: Systems biology-based novel mechanism and traditional Chinese medicine therapy.

Membranous nephropathy (MN) is a renal-limited non-inflammatory autoimmune disease in the glomerulus, which is the second or third main cause of end-stage kidney diseases in patients with primary glomerulonephritis. Substantial achievements have increased our understanding of the aetiology and pathogenesis of murine and human MN. The identification of nephritogenic autoantibodies against neutral endopeptidase, phospholipase A2 receptor (PLA2R) and thrombospondin type-1 domain-containing 7A (THSD7A) antigens provide more specific concept-driven intervention strategies for treatments by specific B cell-targeting monoclonal antibodies to inhibit antibody production and antibody-antigen immune complex deposition. Furthermore, additional antibody specificities for antigens have been discovered, but their pathogenic effects are uncertain. Although anti-PLA2R and anti-THSD7A antibodies as a diagnostic marker is widely used in MN patients, many questions including autoimmune response development, antigenic epitopes, and podocyte damage signalling pathways remain unresolved. This review describes the current available evidence regarding both established and novel molecular mechanisms based on systems biology approaches (gut microbiota, long non-coding RNAs, metabolite biomarkers and DNA methylation) in MN, with an emphasis on clinical findings. This review further summarizes the applications of traditional Chinese medicines such as Tripterygium wilfordii and Astragalus membranaceus for MN treatment. Lastly, this review considers how the identification of novel antibodies/antigens and unresolved questions and future challenges reveal the pathogenesis of MN.

Highly Expressing SCARA5 Promotes Proliferation and Migration of Esophageal Squamous Cell Carcinoma.

Background Thrombospondin type 1 domain-containing 7A (THSD7A) was reported to play a procancer role in esophageal squamous cell carcinoma (ESCC). The aim of the study was to screen the downstream functional genes of THSD7A and explore their functions in ESCC, based on the reported research into THSD7A function and on gene microarrays. Methods We adopted quantitative reverse-transcription polymerase chain reaction (qRT-PCR) and Celigo high-content screening (HCS) technology to screen the downstream genes of THSD7A. The expression level of target genes was examined by PCR, western blot, and immunohistochemistry (IHC). The effects of these target genes on ESCC malignant biological behavior were performed in vivo and in vitro. The Kaplan-Meier (K-M) survival analysis and Cox regression were used to analyze the prognostic significance of target genes in ESCC patients. Experiments in the literature on liver cancer (LC) were repeated to verify the functions of these genes in different tumors. We further explored the cancer-promoting mechanism of target genes in ESCC by sequencing of the genes' exons. Results Scavenger receptor class A member 5 (SCARA5) was proved to be the downstream driving gene of THSD7A. SCARA5 promoted cell proliferation and migration but inhibited apoptosis in ESCC. IHC results confirmed that SCARA5 expression in ESCC exceeded that in normal tissues. The K-M survival analysis indicated that SCARA5 expression quantity was not related to prognosis, but tumor volume and T classification were both the independent prognostic factors. Repetition of experiments in LC in the literature confirmed that SCARA5 had exactly opposite functions in EC and LC. Conclusion SCARA5 was related to the development and occurrence of ESCC. Our findings suggested that it was a potentially diagnostic individualized therapeutic target for ESCC in the future and that its application could possibly be combined with that of upstream THSD7A gene.

Paraneoplastic Glomerular Diseases.

Paraneoplastic glomerular diseases (GNs) are rare manifestations in patients with underlying hematologic and solid organ malignancies and can occur before or after the detection of cancer. In the absence of established algorithms for investigation and reliable tests, they remain difficult to diagnose. Given the heterogeneity and infrequency of cases, the pathogenesis of most paraneoplastic GNs is poorly understood. Most of our recent understanding of paraneoplastic GNs has emerged from the discovery of target antigens in membranous nephropathy such as thrombospondin type-1 domain-containing protein 7A and neural epidermal growth factor-like 1 protein that appear to be promising in differentiating a primary vs paraneoplastic cause of membranous nephropathy. Treatment of paraneoplastic GNs is usually directed at the underlying malignancy. This review will focus on the epidemiology, pathogenesis, and diagnosis of paraneoplastic glomerular processes.