Na+/K+-ATPase stabilization by Hsp70 in the outer stripe of the outer medulla in rats during recovery from a low-protein diet

A low-protein (LP) diet induces injury from energy depletion in renal epithelial cells. Overexpression of heat-shock proteins has been implicated in the restoration of the cytoskeletal anchorage of Na+/K+-ATPase. We tested if Hsp70 stabilizes renal Na+/K+-ATPase attachment to the cytoskeleton from the cortex and the outer stripe of the outer medulla (OSOM) in rats during recovery from a LP diet. Rats were fed with a LP diet (8% protein) for 14 days, and then the rats were recovered with a 24% protein (RP) diet. The control group received a 24% protein (NP) diet. Increased Na+/K+-ATPase dissociation was demonstrated in soluble fraction from OSOM with lower ATP content as a result of LP diet vs NP. Meanwhile, decreased Hsp70 levels in the same fraction were shown. Translocation of Hsp70 to the cytoskeletal injured fraction associated with stabilization of Na+/K+-ATPase was shown in OSOM from LP after in vitro co-incubation of the cytoskeletal fraction of LP and non-cytoskeletal fraction of RP. These effects were abolished by the addition of the anti-Hsp70 antibody. Absence of Na+/K+-ATPase detachment from its cytoskeletal anchorage was demonstrated in proximal duct segments from cortex in LP. Co-immunoprecipitation showed that the amount of Na+/K+-ATPase co-precipitating with Hsp70 increased in the OSOM as a result of the LP diet. In the cortex tissues from rats fed the LP and the RP diet, the interaction of both proteins were similar to the control groups. Our results indicate that Hsp70 has a critical role in protecting the integrity of the cytoskeletal anchorage of Na+/K+-ATPase during recovery from ATP-depleted injury resulting from LP in OSOM

EBV-positive diffuse large B-cell lymphoma in a patient with primary Sjögren’s syndrome and membranous glomerulonephritis

<p>Abstract</p> <p>Background</p> <p>Sjögren’s syndrome is a systemic autoimmune disease in which lymphatic cells destroy the salivary and lacrimal glands. Glomerulonephritis is thought to be a rare occurrence in primary Sjögren’s syndrome. Furthermore, concurrent glomerular involvement and lymphoma in patients with Sjögren’s syndrome has seldom been reported.</p> <p>Case presentation</p> <p>A 52-year-old woman with primary Sjögren’s syndrome developed membranous glomerulonephritis and Epstein-Barr virus-positive diffuse large B-cell lymphoma (DLBCL). She was diagnosed with Sjögren’s syndrome based on the dry eyes, dry mouth, positive anti-nuclear antibody test, anti-Ro (SS-A) antibody, salivary gland biopsy, and salivary scintigraphy. Moreover, renal biopsy confirmed the diagnosis of membranous glomerulonephritis. Three months later, her small bowel was perforated with pneumoperitoneum, and the biopsy revealed Epstein-Barr virus-positive DLBCL.</p> <p>Conclusions</p> <p>We observed the first case of primary Sjögren’s syndrome associated with Epstein-Barr Virus-positive DLBCL and membranous glomerulonephritis. Because of the possibility of malignancy-associated membranous glomerulonephritis in patients with primary Sjögren’s syndrome, we should be careful and examine such patients for hidden malignancy.</p