The M-type phospholipase A2 receptor (PLA2R) is a target autoantigen in adult idiopathic membranous nephropathy (MN), but the prevalence of autoantibodies against PLA2R is unknown among Chinese patients with MN. Here, we measured anti-PLA2R antibody in the serum of 60 patients with idiopathic MN, 20 with lupus-associated MN, 16 with hepatitis B (HBV)-associated MN, and 10 with tumorassociated MN. Among patients with idiopathic MN, 49 (82%) had detectable anti-PLA2R autoantibodies using a Western blot assay; an assay with greater sensitivity detected very low titers of anti-PLA2R in 10 of the remaining 11 patients. Using the standard assay, we detected anti-PLA2R antibody in only 1 patient with lupus, 1 with HBV, and 3 with cancer, producing an overall specificity of 89% in this cohort limited to patients with secondary MN. The enhanced assay detected low titers of anti-PLA2R in only 2 additional samples of HBV-associated MN. In summary, these results suggest that PLA2R is a major target antigen in Chinese idiopathic MN and that detection of anti-PLA2R is a sensitive test for idiopathic MN.

NEET proteins belong to a highly conserved group of [2Fe-2S] proteins found across all kingdoms of life. Due to their unique 2Fe-2S cluster structure, they play a key role in the regulation of many different redox and oxidation processes. In eukaryotes, NEET proteins are localized to the mitochondria, ER and the membranes connecting these organelles (MAM), and are involved in the control of multiple processes, ranging from autophagy and apoptosis to ferroptosis, oxidative stress, cell proliferation, redox control and iron and iron-sulfur homeostasis. Through their different functions and interactions with key proteins such as VDAC and Bcl-2, NEET proteins coordinate different mitochondrial, MAM, ER and cytosolic processes and functions and regulate major signaling molecules such as calcium and reactive oxygen species. Owing to their central role in cells, NEET proteins are associated with numerous human maladies including cancer, metabolic diseases, diabetes, obesity, and neurodegenerative diseases. In recent years, a new and exciting role for NEET proteins was uncovered, i.e., the regulation of mitochondrial dynamics and morphology. This new role places NEET proteins at the forefront of studies into cancer and different metabolic diseases, both associated with the regulation of mitochondrial dynamics. Here we review recent studies focused on the evolution, biological role, and structure of NEET proteins, as well as discuss different studies conducted on NEET protein function using transgenic organisms. We further discuss the different strategies used in the development of drugs that target NEET proteins, and link these with the different roles of NEET proteins in cells.

Serum phospholipase A2 receptor antibodies (SAbs) and glomerular phospholipase A2 receptor antigen (GAg) deposits have been observed in idiopathic membranous nephropathy (IMN). However, the clinical application of these two biomarkers, particularly GAg deposition, needs to be further evaluated. We measured SAb concentration by ELISA and GAg deposition by immunofluorescence in 572 patients with biopsy-proven IMN. Overall, 68.5% of patients (392 of 572) had detectable SAb (SAb+), and 98.7% of patients who were SAb+ (387 of 392) and 70.6% of patients who were SAb- (127 of 180) had GAg deposition (GAg+). Compared with patients who were SAb-/GAg+, patients who were SAb+/GAg+ exhibited higher levels of proteinuria (P<0.001) and a lower chance of proteinuria remission (P<0.001). In 52 patients who underwent repeat biopsies, patients who did not achieve remission had a higher SAb+ rate on the first biopsy than patients who went into remission (P=0.001). Furthermore, SAb+ levels persisted in patients who did not achieve remission but significantly decreased in patients who achieved remission by the second biopsy. Patients who did not achieve remission also had a higher GAg+ rate on the first biopsy than patients who achieved remission (P<0.01). Sustained GAg+ deposits correlated with disease relapse. In conclusion, combining the measurements of SAb levels and detection of GAg deposition may provide additional information regarding diagnoses, treatment response, and disease relapse in patients with IMN.