The uptake and metabolism of long chain fatty acids (LCFA) are critical to many physiological and cellular processes. Aberrant accumulation or depletion of LCFA underlie the pathology of numerous metabolic diseases. Protein-mediated transport of LCFA has been proposed as the major mode of LCFA uptake and activation. Several proteins have been identified to be involved in LCFA uptake. This review focuses on the SLC27 family of fatty acid transport proteins, also known as FATPs, with an emphasis on the gain- and loss-of-function animal models that elucidate the functions of FATPs in vivo and how these transport proteins play a role in physiological and pathological situations.

Olfactory inputs help coordinate food appreciation and selection, but their role in systemic physiology and energy balance is poorly understood. Here we demonstrate that mice upon conditional ablation of mature olfactory sensory neurons (OSNs) are resistant to diet-induced obesity accompanied by increased thermogenesis in brown and inguinal fat depots. Acute loss of smell perception after obesity onset not only abrogated further weight gain but also improved fat mass and insulin resistance. Reduced olfactory input stimulates sympathetic nerve activity, resulting in activation of β-adrenergic receptors on white and brown adipocytes to promote lipolysis. Conversely, conditional ablation of the IGF1 receptor in OSNs enhances olfactory performance in mice and leads to increased adiposity and insulin resistance. These findings unravel a new bidirectional function for the olfactory system in controlling energy homeostasis in response to sensory and hormonal signals.

Objectives Studies suggest that rheumatoid arthritis (RA)-related autoimmunity is initiated at a mucosal site. However, the factors associated with the mucosal generation of this autoimmunity are unknown, especially in individuals who are at-risk for future RA. Therefore, we tested anti-cyclic citrullinated peptide (anti-CCP) antibodies in the sputum of RA-free first-degree relatives (FDRs) of RA patients and patients with classifiable RA. Methods We evaluated induced sputum and serum from 67 FDRs and 20 RA subjects for anti-CCP-IgA and anti-CCP-IgG, with cut-off levels for positivity determined in a control population. Sputum was also evaluated for cell counts, neutrophil extracellular traps (NETs) using sandwich ELISAs for protein/nucleic acid complexes, and total citrulline. Results Sputum anti-CCP-IgA and/or anti-CCP-IgG was positive in 17/67 (25%) FDRs and 14/20 (70%) RA subjects, including a portion of FDRs who were serum anti-CCP negative. In FDRs, elevations of sputum anti-CCP-IgA and anti-CCP-IgG were associated with elevated sputum cell counts and levels of NET complexes. Anti-CCP-IgA was associated with ever-smoking and elevated sputum citrulline levels. Conclusions Anti-CCP is elevated in the sputum of FDRs, including seronegative FDRs, suggesting the lung may be one site of anti-CCP generation in this population. The association of anti-CCP with elevated cell counts and NET levels in FDRs supports a hypothesis that local airway inflammation and NET formation may drive anti-CCP production in the lung and may promote the early stages of RA development. Longitudinal studies are needed to follow the evolution of these processes relative to the development of systemic autoimmunity and articular RA.

Biomarkers such as DNA, RNA, and protein are powerful tools in clinical diagnostics and therapeutic development for many diseases. Identifying RNA expression at the single cell level within the morphological context by RNA in situ hybridization provides a great deal of information on gene expression changes over conventional techniques that analyze bulk tissue, yet widespread use of this technique in the clinical setting has been hampered by the dearth of automated RNA ISH assays. Here we present an automated version of the RNA ISH technology RNAscope that is adaptable to multiple automation platforms. The automated RNAscope assay yields a high signal‐to‐noise ratio with little to no background staining and results comparable to the manual assay. In addition, the automated duplex RNAscope assay was able to detect two biomarkers simultaneously. Lastly, assay consistency and reproducibility were confirmed by quantification of TATA‐box binding protein (TBP) mRNA signals across multiple lots and multiple experiments. Taken together, the data presented in this study demonstrate that the automated RNAscope technology is a high performance RNA ISH assay with broad applicability in biomarker research and diagnostic assay development. J. Cell. Biochem. 117: 2201–2208, 2016. © 2016 The Authors. Journal of Cellular Biochemistry Published by Wiley Periodicals, Inc.

Summary Brown adipose tissue (BAT) possesses the inherent ability to dissipate metabolic energy as heat through uncoupled mitochondrial respiration. An essential component of the mitochondrial electron transport chain is coenzyme Q (CoQ). While cells mostly synthesize CoQ endogenously, exogenous supplementation with CoQ has been successful as a therapy for patients with CoQ deficiency. However, which tissues depend on exogenous CoQ uptake as well as the mechanism by which CoQ is taken up by cells and the role of this process in BAT function is not well understood. Here we report that the scavenger receptor CD36 drives the uptake of CoQ by BAT and is required for normal BAT function. BAT from mice lacking CD36 displays CoQ deficiency, impaired CoQ uptake, hypertrophy, altered lipid metabolism, mitochondrial dysfunction, and defective non-shivering thermogenesis. Together, these data reveal an important new role for the systemic transport of CoQ to BAT and its function in thermogenesis.