👤 Paula J Stokes

Amyloidosis derived from apolipoprotein C-II (AApoCII) is a recently discovered, rare form of amyloidosis. Data on clinical presentations and natural history are very limited. This study defines the clinicopathologic, proteomic, and outcome characteristics of renal AApoCII. Case series. Twenty-five renal AApoCII cases were identified from the Mayo Clinic Tissue Proteomics Laboratory archives from January 2008 through January 2024. All patients were White, 19 were≥65 years old at diagnosis, and 18 were female. Seven had a family history of chronic kidney disease (CKD). Patients presented with proteinuria (median 3.3g/day) and reduced kidney function (n=16; median creatinine, 1.6mg/dL). No patients had clinical evidence of other organ involvement by amyloidosis or features of monogenic hypertriglyceridemia. Histologically, amyloid deposits were often weakly positive for Congo red and involved glomeruli in all cases (with a nodular pattern in 22), whereas extraglomerular involvement was less common and generally mild. Proteomic analysis revealed abundant spectra for Apo C-II and for all 3 amyloid signature proteins (apolipoprotein E, apolipoprotein A-IV, and serum amyloid P) in all cases and detected an Apo C-II variant in 14 (K19T [p.Lys41Thr] in 12 and E47V [p.Glu69Val] in 2). Among 22 patients with follow-up information available, there were 12 end-stage kidney disease (ESKD) events and 2 deaths without ESKD during an average follow-up period of 75.5±12.5 (SE) months. Retrospective design, small sample size, APOC2 gene sequencing performed in a smaller subset. AApoCII mostly affects the kidney and manifests in the elderly with proteinuria and CKD. A minority of these patients had a family history of kidney disease. Kidney failure occurred in about half, whereas overall survival was more favorable. Amyloidosis derived from apolipoprotein C-II (AApoCII) is very rare, and data on clinicopathologic and outcome characteristics are scant. This study of 25 patients with AApoCII diagnosed by mass spectrometry at the Mayo Clinic Tissue Proteomics Laboratory revealed that most patients were elderly White females who presented with proteinuria and reduced kidney function, without involvement of other organs. A family history of kidney disease was often lacking. Pathologically, most cases exhibited nodular glomerular involvement. Proteomic analysis revealed abundant protein spectra for Apo C-II and amyloid signature proteins, and identified an Apo C-II variant in over half of cases (most commonly the p.Lys41Thr variant). The cumulative incidence of kidney failure was over 50% at 5 years follow-up. Only 4 deaths occurred over an average follow-up period of 76 months. Show less

Finding biomarkers that provide shared link between disease severity, drug-induced pharmacodynamic effects and response status in human trials can provide number of values for patient benefits: elucidating current therapeutic mechanism-of-action, and, back-translating to fast-track development of next-generation therapeutics. Both opportunities are predicated on proactive generation of human molecular profiles that capture longitudinal trajectories before and after pharmacological intervention. Here, we present the largest plasma proteomic biomarker dataset available to-date and the corresponding analyses from placebo-controlled Phase III clinical trials of the phosphodiesterase type 4 inhibitor apremilast in psoriasis (PSOR), psoriatic arthritis (PsA), and ankylosing spondylitis (AS) from 526 subjects overall. Using approximately 150 plasma analytes tracked across three time points, we identified IL-17A and KLK-7 as biomarkers for disease severity and apremilast pharmacodynamic effect in psoriasis patients. Combined decline rate of KLK-7, PEDF, MDC and ANGPTL4 by Week 16 represented biomarkers for the responder subgroup, shedding insights into therapeutic mechanisms. In ankylosing spondylitis patients, IL-6 and LRG-1 were identified as biomarkers with concordance to disease severity. Apremilast-induced LRG-1 increase was consistent with the overall lack of efficacy in ankylosing spondylitis. Taken together, these findings expanded the mechanistic knowledge base of apremilast and provided translational foundations to accelerate future efforts including compound differentiation, combination, and repurposing. Show less

Recessive inheritance of mutations in ceroid neuronal lipofuscinosis type 3 (CLN3) results in juvenile neuronal ceroid lipofuscinosis (JNCL), a childhood neurodegenerative disease with symptoms including loss of vision, seizures, and motor and mental decline. CLN3p is a transmembrane protein with undefined function. Using a Cln3 reporter mouse harboring a nuclear-localized bacterial beta-galactosidase (beta-Gal) gene driven by the native Cln3 promoter, we detected beta-Gal most prominently in epithelial cells of skin, colon, lung, and kidney. In the kidney, beta-Gal-positive nuclei were predominant in medullary collecting duct principal cells, with increased expression along the medullary osmotic gradient. Quantification of Cln3 transcript levels from kidneys of wild-type (Cln3(+/+)) mice corroborated this expression gradient. Reporter mouse-derived renal epithelial cultures demonstrated a tonicity-dependent increase in beta-Gal expression. RT-quantitative PCR determination of Cln3 transcript levels further supported osmoregulation at the Cln3 locus. In vivo, osmoresponsiveness of Cln3 was demonstrated by reduction of medullary Cln3 transcript abundance after furosemide administration. Primary cultures of epithelial cells of the inner medulla from Cln3(lacZ/lacZ) (CLN3p-null) mice showed no defect in osmolyte accumulation or taurine flux, arguing against a requirement for CLN3p in osmolyte import or synthesis. CLN3p-deficient mice with free access to water showed a mild urine-concentrating defect but, upon water deprivation, were able to concentrate their urine normally. Unexpectedly, we found that CLN3p-deficient mice were hyperkalemic and had a low fractional excretion of K(+). Together, these findings suggest an osmoregulated role for CLN3p in renal control of water and K(+) balance. Show less

Skeletal stem and progenitor populations provide a platform for cell-based tissue regeneration strategies. Optimized conditions for ex vivo expansion will be critical and use of serum-free culture may allow enhanced modelling of differentiation potential. Maintenance of human foetal femur-derived cells in a chemically defined medium (CDM) with activin A and fibroblast growth factor-2 generated a unique undifferentiated cell population in comparison to basal cultures, with significantly reduced amino acid depletion, appearance and turnover, reduced alkaline phosphatase (ALP) activity and loss of type I and II collagen expression demonstrated by fluorescence immunocytochemistry. Microarray analysis demonstrated up-regulation of CLU, OSR2, POSTN and RABGAP1 and down-regulation of differentiation-associated genes CRYAB, CSRP1, EPAS1, GREM1, MT1X and SRGN as validated by quantitative real-time polymerase chain reaction. Application of osteogenic conditions to CDM cultures demonstrated partial rescue of ALP activity. In contrast, the addition of bone morphogenetic protein-2 (BMP-2) resulted in reduced ALP levels, increased amino acid metabolism and, strikingly, a marked shift to a cobblestone-like cellular morphology, with expression of SOX-2 and SOX-9 but not STRO-1 as shown by immunocytochemistry, and significantly altered expression of metabolic genes (GFPT2, SC4MOL and SQLE), genes involved in morphogenesis (SOX15 and WIF1) and differentiation potential (C1orf19, CHSY-2,DUSP6, HMGCS1 and PPL). These studies demonstrate the use of an intermediary foetal cellular model for differentiation studies in chemically defined conditions and indicate the in vitro reconstruction of the mesenchymal condensation phenotype in the presence of BMP-2, with implications therein for rescue studies, screening assays and skeletal regeneration research. Show less