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Fibrillary glomerulonephritis (FGN) is a rare glomerular disease. Kidney biopsy is required to establish the diagnosis. Recent studies have identified abundant glomerular deposition of DNAJB9 as a unique histological marker of FGN. We developed an immunoprecipitation-based multiple reaction monitoring method to measure serum levels of DNAJB9. We detected a 4-fold higher abundance of serum DNAJB9 in FGN patients when compared to controls, including patients with other glomerular diseases. Serum DNAJB9 levels were also negatively associated with estimated glomerular filtration rate in patients with FGN. Serum DNAJB9 levels accurately predicted FGN with moderate sensitivity (67%) and with high specificity (98%) and positive and negative predictive value (89% and 95%, respectively). A receiver operating curve analysis demonstrated an AUC of 0.958. These results suggest that serum levels of DNAJB9 could be a valuable marker to predict FGN, with the potential to complement kidney biopsy for the diagnosis of FGN.Kidney International (2019) 95, 1269-1272; https://doi.F ibrillary glomerulonephritis (FGN) is a glomerular disease observed in z1% of native renal biopsies. 1,2 Patients present with proteinuria, hematuria, and impaired renal function. A renal biopsy is required to diagnose FGN. [1][2][3][4] Traditional diagnostic criteria for FGN include the finding, by electron microscopy, of randomly oriented fibrils measuring 10-30 nm in diameter in the mesangium and/or along the glomerular basement membranes. On immunofluorescence, the deposits most commonly stain for IgG, both k and l light chains, and C3. Light microscopy usually reveals mesangial expansion/hypercellularity, with or without duplication of the glomerular basement membranes microscopy. 3 Recently, we 5,6 and others 7 have identified DNAJB9 as a biomarker protein in FGN. Normally, DNAJB9 is localized to endoplasmic reticulum and protects the cells from stress-mediated apoptosis. However, this protein was overly abundant in the extracellular space of FGN glomeruli and absent from glomeruli of healthy controls and a wide variety of non-FGN glomerular diseases (NFGNGDs). 5 Given that FGN is characterized by increased glomerular deposition of DNAJB9, in this study, we measured serum DNAJB9 concentrations in patients with renal disease to assess its potential for distinguishing FGN patients from NFGNGD controls. RESULTSWe wanted to assess whether DNAJB9 has potential as a serum biomarker for FGN. To accomplish this, we developed an immuno-MRM method for measuring serum levels of DNAJB9 in FGN patients and negative controls. FGN patients had significantly higher levels of serum DNAJB9. Multivariate and univariate analyses have suggested that serum DNAJB9 has significant predictive power for FGN. FGN patients have higher serum DNAJB9 levelsFigure 1a 8,9 presents the serum concentrations (expressed in nM) of DNAJB9 in FGN patients and negative controls (normal controls, multiple myeloma patients, NFGNGD patients, and AL patients). FGN patients had significantly hig...

The adenylyl cyclase‐cyclic AMP (cAMP) second messenger pathway has been proposed to regulate myelin gene expression; however, a clear correlation between endogenous cAMP levels and myelin‐specific mRNA levels has never been demonstrated during the induction or maintenance of differentiation by the myelinating Schwann cell. Endogenous cAMP levels decreased to 8–10% of normal nerve by 3 days after crush or permanent transection injury of adult rat sciatic nerve. Whereas levels remained low after transection injury, cAMP levels reached only 27% of the normal values by 35 days after crush injury. Because P0 mRNA levels were 60% of normal levels by 14 days and 100% by 21 days after crush injury, cAMP increased only well after P0 gene induction. cAMP, therefore, does not appear to trigger myelin gene induction but may be involved in myelin assembly or maintenance. Forskolin, an activator of adenylyl cyclase, increased endoneurial cAMP levels only in the normal nerve, and in the crushed nerve beginning at 16 days after injury, but at no time in the transected nerve. Only by treating transected nerve with 3‐isobutyl‐1‐methylxanthine (IBMX), an inhibitor of cAMP phosphodiesterases, in combination with forskolin was it possible to increase cAMP levels. No induction of myelin genes, however, was observed with short‐ or long‐term treatment with IBMX and forskolin in the transected nerve. A three‐fold increase in phosphodiesterase activity was observed at 35 days after both injuries, and a nonmyelinated nerve was shown to have even higher activity. These experiments, therefore, suggest an important role for phosphodiesterase in the inactivation of this second messenger‐dependent stimuli when Schwann cells are non‐myelinating, such as after sciatic nerve injury or in the nonmyelinated nerve, which again implies that cAMP may be required for the maintenance of the myelin sheath.

Dysfunction of glutamate neurotransmission in the nucleus accumbens (NAc) has been implicated in the pathophysiology of alcohol use disorders (AUD). Neurogranin (Ng) is exclusively expressed in the brain and mediates N-methyl-D-aspartate receptor (NMDAR) hypo-function by regulating the intracellular calcium-calmodulin (Ca 2+ -CaM) pathway. Interestingly, Ng null mice (Ng -/mice) demonstrate increased alcohol drinking compared to wild-type mice, while also showing less tolerance to the effect of alcohol. To identify the molecular mechanism related to alcohol seeking, we utilized both in vivo microdialysis and label-free quantification proteomics comparing Ng genotype and effects of alcohol treatment on the NAc. There is significant difference in glutamate and GABA neurotransmission between genotypes, however, alcohol administration normalizes both glutamate and GABA levels in the NAc. Using label-free proteomics, we identified 427 protein expression changes against alcohol treatment in the NAc among 4,347 total proteins detected. Bioinformatics analyses revealed significant molecular differences in Ng null mice in response to acute alcohol treatment. Ingenuity pathway analysis found that the AKT network was altered significantly between genotypes, which might increase the sensitivity of alcohol in Ng null mice. Finally, our pharmacoproteomics results illustrate a possible molecular basis for the NAc-mediated alcohol seeking, which provides a better understanding of the Ngmediated signaling in AUD.