👤 Elizabeth Sparks

White adipose tissue (WAT) expansion occurs through generation of new adipocytes from adipose progenitor cells (APC). The objective of this study was to characterize and validate a new transcriptional profile of APC. Single-cell (sc)/nuclei (sn) RNA-Seq was performed on nuclei from whole WAT (n = 20), cells from WAT stromal vascular fraction (n = 5), and cultured APC in vitro (n = 8) using ICELL8 smart-Seq technology. Additional snRNA-Seq was performed on WAT using 10x genomic platform. Pseudotime analyses and differentiation of hiPSCs was used to track the temporal patterns of novel gene signatures. Immunohistochemistry was performed to validate a new marker. A pre-adipocyte population was found across the four independent datasets that expressed known pre-adipocyte markers (ZNF423 and DLK1) in addition to genes typically associated with neurogenes (DPP10, PTRPT, CTNNA2, NRXN3, CTNNA2, PTPRD, CNTNAP2 and RBFOX1). The expression of these genes were temporally regulated with adipocyte differentiation. Immunohistochemistry analyses confirmed these pre-adipocytes are located in the neurovascular niche of WAT but are not neurons or endothelial cells. This work has defined a new transcriptional signature of pre-adipocytes in human subcutaneuous WAT that are distinct from mesencyhmal stem cell populations and represent novel targets for WAT expansion. Show less

Declines in skeletal muscle and cognitive function in older adults have been linked to abnormalities in abdominal subcutaneous adipose tissue (ASAT), yet the underlying molecular mediators remain poorly understood. Here, leveraging ASAT transcriptomics and explant-conditioned media proteomics from participants in the Study of Muscle, Mobility and Aging (SOMMA; age ≥70 years, n = 229), we identified ASAT gene clusters and secreted proteins strongly associated with comprehensive assessments of physical and cognitive function in older adults. ASAT inflammation and secreted immunoglobulins were identified as key signatures of aging-associated physical and cognitive performance limitations. Systems genetics analysis confirmed secreted-SERPINF1 as a negative regulator of skeletal muscle contraction and highlighted its potential role in inducing inflammation in the heart in silico. Additionally, novel ASAT-secreted proteins such as NID2 and APOA4 were implicated in mediating ASAT crosstalk with skeletal muscle and brain in silico. Our framework provides insights into ASAT-driven tissue crosstalk underlying physical and cognitive performance in older adults and offers a valuable resource for understanding the role of ASAT in human aging. Show less

Declines in skeletal muscle and cognitive function in older adults have been linked to abnormalities in abdominal subcutaneous adipose tissue (ASAT), yet the underlying molecular mediators remain poorly understood. Here, leveraging ASAT transcriptomics and explant-conditioned media proteomics from participants in the Study of Muscle, Mobility and Aging (SOMMA; age ≥70 years, n = 229), we identified ASAT gene clusters and secreted proteins strongly associated with comprehensive assessments of physical and cognitive function in older adults. ASAT inflammation and secreted immunoglobulins were identified as key signatures of aging-associated physical and cognitive performance limitations. Systems genetics analysis confirmed secreted-SERPINF1 as a negative regulator of skeletal muscle contraction and highlighted its potential role in inducing inflammation in the heart Show less

Bardet-Biedl Syndrome (BBS) is a pleiotropic genetic disease caused by the dysfunction of primary cilia. The immune system of patients with ciliopathies has not been investigated. However, there are multiple indications that the impairment of the processes typically associated with cilia may have influence on the hematopoietic compartment and immunity. In this study, we analyze clinical data of BBS patients and corresponding mouse models carrying mutations in Bbs4 or Bbs18. We find that BBS patients have a higher prevalence of certain autoimmune diseases. Both BBS patients and animal models have altered red blood cell and platelet compartments, as well as elevated white blood cell levels. Some of the hematopoietic system alterations are associated with BBS-induced obesity. Moreover, we observe that the development and homeostasis of B cells in mice is regulated by the transport complex BBSome, whose dysfunction is a common cause of BBS. The BBSome limits canonical WNT signaling and increases CXCL12 levels in bone marrow stromal cells. Taken together, our study reveals a connection between a ciliopathy and dysregulated immune and hematopoietic systems. Show less

Dysregulation of neuropeptides may play an important role in aging-induced impairments. Among them, pituitary adenylate cyclase-activating polypeptide (PACAP) is a potent cytoprotective peptide that provides an endogenous control against a variety of tissue-damaging stimuli. We hypothesized that the progressive decline of PACAP throughout life and the well-known general cytoprotective effects of PACAP lead to age-related pathophysiological changes in PACAP deficiency, supported by the increased vulnerability to various stressors of animals partially or totally lacking PACAP. Using young and aging CD1 PACAP knockout (KO) and wild type (WT) mice, we demonstrated pre-senile amyloidosis in young PACAP KO animals and showed that senile amyloidosis appeared accelerated, more generalized, more severe, and affected more individuals. Histopathology showed age-related systemic amyloidosis with mainly kidney, spleen, liver, skin, thyroid, intestinal, tracheal, and esophageal involvement. Mass spectrometry-based proteomic analysis, reconfirmed with immunohistochemistry, revealed that apolipoprotein-AIV was the main amyloid protein in the deposits together with several accompanying proteins. Although the local amyloidogenic protein expression was disturbed in KO animals, no difference was found in laboratory lipid parameters, suggesting a complex pathway leading to increased age-related degeneration with amyloid deposits in the absence of PACAP. In spite of no marked inflammatory histological changes or blood test parameters, we detected a disturbed cytokine profile that possibly creates a pro-inflammatory milieu favoring amyloid deposition. In summary, here we describe accelerated systemic senile amyloidosis in PACAP gene-deficient mice, which might indicate an early aging phenomenon in this mouse strain. Thus, PACAP KO mice could serve as a model of accelerated aging with human relevance. © 2018 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland. Show less

The study sought to assess the safety, feasibility, and effect of diltiazem as disease-modifying therapy for at-risk hypertrophic cardiomyopathy (HCM) mutation carriers. HCM is caused by sarcomere mutations and characterized by left ventricular hypertrophy (LVH) with increased risk of heart failure and sudden death. HCM typically cannot be diagnosed early in life, although subtle phenotypes are present. Animal studies indicate that intracellular calcium handling is altered before LVH develops. Furthermore, early treatment with diltiazem appeared to attenuate disease emergence. In a pilot, double-blind trial, we randomly assigned 38 sarcomere mutation carriers without LVH (mean 15.8 years of age) to therapy with diltiazem 360 mg/day (or 5 mg/kg/day) or placebo. Treatment duration ranged from 12 to 42 months (median 25 months). Study procedures included electrocardiography, echocardiography, cardiac magnetic resonance imaging, and serum biomarker measurement. Diltiazem was not associated with serious adverse events. Heart rate and blood pressure did not differ significantly between groups. However, mean left ventricular (LV) end-diastolic diameter improved toward normal in the diltiazem group but decreased further in controls (change in z-scores, +0.6 vs. -0.5; p < 0.001). Mean LV thickness-to-dimension ratio was stable in the diltiazem group but increased in controls (-0.02 vs. +0.15; p = 0.04). Among MYBPC3 mutation carriers, LV wall thickness and mass, diastolic filling, and cardiac troponin I levels improved in those taking diltiazem compared with controls. Four participants developed overt HCM, 2 in each treatment group. Pre-clinical administration of diltiazem is safe and may improve early LV remodeling in HCM. This novel strategy merits further exploration. (Treatment of Preclinical Hypertrophic Cardiomyopathy With Diltiazem; NCT00319982). Show less

The myosin-binding protein C isoform 3 (MYBPC3) variant Arg502Trp has been identified in multiple hypertrophic cardiomyopathy (HCM) cases, but compelling evidence to support or refute the pathogenicity of this variant is lacking. To determine the prevalence, origin and clinical significance of the MYBPC3 Arg502Trp variant. The prevalence of MYBPC3 Arg502Trp was ascertained in 1414 sequential HCM patients of primarily European descent. MYBPC3 Arg502Trp was identified in 34 of these 1414 unrelated HCM patients. Segregation of MYBPC3 Arg502Trp with clinical status was assessed in family members. Disease haplotypes were examined in 17 families using two loci flanking MYBPC3. Family studies identified an additional 43 variant carriers, many with manifest disease, yielding a calculated odds ratio of 11 000:1 for segregation of MYBPC3 Arg502Trp with HCM. Analyses in 17 families showed at least 4 independent haplotypes flanked MYBPC3 Arg502Trp. Eight individuals (4 probands and 4 family members) also had another sarcomere protein gene mutation. Major adverse clinical events occurred in approximately 30% of MYBPC3 Arg502Trp carriers by age 50; these were significantly more likely (P<0.0001) when another sarcomere mutation was present. MYBPC3 Arg502Trp is the most common and recurrent pathogenic mutation in a diverse primarily European descent HCM cohort, occurring in 2.4% of patients. MYBPC3 Arg502Trp conveys a 340-fold increased risk for HCM by 45 years of age, when more than 50% of carriers have overt disease. HCM prognosis worsens when MYBPC3 Arg502Trp occurs in the setting of another sarcomere protein gene mutation. Show less