IDOL regulates systemic energy balance through control of neuronal VLDLR expression.

Liver X receptors limit cellular lipid uptake by stimulating the transcription of Inducible Degrader of the LDL Receptor (IDOL), an E3 ubiquitin ligase that targets lipoprotein receptors for degradation. The function of IDOL in systemic metabolism is incompletely understood. Here we show that loss of IDOL in mice protects against the development of diet-induced obesity and metabolic dysfunction by altering food intake and thermogenesis. Unexpectedly, analysis of tissue-specific knockout mice revealed that IDOL affects energy balance, not through its actions in peripheral metabolic tissues (liver, adipose, endothelium, intestine, skeletal muscle), but by controlling lipoprotein receptor abundance in neurons. Single-cell RNA sequencing of the hypothalamus demonstrated that IDOL deletion altered gene expression linked to control of metabolism. Finally, we identify VLDLR rather than LDLR as the primary mediator of IDOL effects on energy balance. These studies identify a role for the neuronal IDOL-VLDLR pathway in metabolic homeostasis and diet-induced obesity

Higher COVID-19 pneumonia risk associated with anti-IFN-α than with anti-IFN-ω auto-Abs in children

We found that 19 (10.4%) of 183 unvaccinated children hospitalized for COVID-19 pneumonia had autoantibodies (auto-Abs) neutralizing type I IFNs (IFN-alpha 2 in 10 patients: IFN-alpha 2 only in three, IFN-alpha 2 plus IFN-omega in five, and IFN-alpha 2, IFN-omega plus IFN-beta in two; IFN-omega only in nine patients). Seven children (3.8%) had Abs neutralizing at least 10 ng/ml of one IFN, whereas the other 12 (6.6%) had Abs neutralizing only 100 pg/ml. The auto-Abs neutralized both unglycosylated and glycosylated IFNs. We also detected auto-Abs neutralizing 100 pg/ml IFN-alpha 2 in 4 of 2,267 uninfected children (0.2%) and auto-Abs neutralizing IFN-omega in 45 children (2%). The odds ratios (ORs) for life-threatening COVID-19 pneumonia were, therefore, higher for auto-Abs neutralizing IFN-alpha 2 only (OR [95% CI] = 67.6 [5.7-9,196.6]) than for auto-Abs neutralizing IFN-. only (OR [95% CI] = 2.6 [1.2-5.3]). ORs were also higher for auto-Abs neutralizing high concentrations (OR [95% CI] = 12.9 [4.6-35.9]) than for those neutralizing low concentrations (OR [95% CI] = 5.5 [3.1-9.6]) of IFN-omega and/or IFN-alpha 2

Integration of Metabolic and Reproductive Cues in the Neural Control of Feeding

Metabolism and reproduction are linked homeostatic processes. This linkage becomes particularly important for animals who gestate their young, as gestation and postpartum care are energetically taxing life stages. Indeed, long- and short-term measures of metabolic reserve and availability, adiposity and feeding, gate reproductive processes in mammals with ovaries. Many neuronal nodes and circuits that help mediate this tradeoff are located in the hypothalamus. As an important component of energy intake, feeding nodes have been investigated as responsive to reproductive cues such as gonadal hormones for many decades. Feeding is a complex behavior, tapping into both homeostatic and hedonic mechanisms. As such, there are many locations where metabolic and reproductive status may integrate and affect feeding behavior. This thesis explores how the tuberal nucleus (TN), a relatively new feeding node, may integrate metabolic and reproductive cues to affect food intake. Using the Cre-lox system and viral stereotaxic injections, somatostatin neurons in the TN (TNSST) were selectively manipulated to interrogate neuronal function. Chemogenetic activation of TNSST neurons increased food intake across sexes, but cell autonomous caspase ablation only decreased food intake in female mice (mice with ovaries) during the night of proestrus, when circulating hormones like estradiol are high. This apparent effect of estradiol was only evident in animals with a low body weight, and the inverse correlation of food intake and body weight during proestrus was completely eliminated with TNSST neuron ablation. Further analysis revealed that this body weight effect may be primarily determined by adiposity, as high levels of hypothalamic estradiol seem to increase communication between TNSST neurons and various adipocyte depots. This may be a direct effect of estradiol on TNSST neurons, as these neurons are both estrogen sensitive and responsive. Ongoing fat transplantation studies confirm the adipose dependency of this effect. Together, this dissertation proposes a model whereby TNSST neurons activate during periods of fertility to induce food intake when body reserves are low. Thus, sex differential recruitment and/or activation of TNSST neurons may work to mitigate the effects of sex steroids on behavioral feeding output. This dissertation research illustrates how gonadal steroid modulation of neuronal circuits can be context-dependent and gated by other physiological signals. Furthermore, this project illustrates how sex as a singular, coherent biological variable is insufficient for current explorations into the contributions of sexed physiologies to feeding behavior. Thus, this dissertation also proposes a framework shift to a “sex variables” paradigm that recognizes the limitations of binary, internally consistent sex in favor of a more contextual and expansive definition of sex and sexed physiologies

Sexes on the brain: Sex as multiple biological variables in the neuronal control of feeding

Neuronal interactions at the level of vagal, homeostatic, and hedonic circuitry work to regulate the neuronal control of feeding. This integrative system appears to vary across sex and gender in the animal and human worlds. Most feeding research investigating these variations across sex and gender focus on how the organizational and activational mechanisms of hormones contribute to these differences. However, in limited studies spanning both the central and peripheral nervous systems, sex differences in feeding have been shown to manifest not just at the level of the hormonal, but also at the chromosomal, epigenetic, cellular, and even circuitry levels to alter food intake. In this review, we provide a brief orientation to the current understanding of how these neuronal systems interact before dissecting selected studies from the recent literature to exemplify how feeding physiology at all levels can be affected by the various components of sex

Multiple sclerosis patient-specific primary neurons differentiated from urinary renal epithelial cells via induced pluripotent stem cells

As multiple sclerosis research progresses, it is pertinent to continue to develop suitable paradigms to allow for ever more sophisticated investigations. Animal models of multiple sclerosis, despite their continuing contributions to the field, may not be the most prudent for every experiment. Indeed, such may be either insufficient to reflect the functional impact of human genetic variations or unsuitable for drug screenings. Thus, we have established a cell- and patient-specific paradigm to provide an in vitro model within which to perform future genetic investigations. Renal proximal tubule epithelial cells were isolated from multiple sclerosis patients' urine and transfected with pluripotency-inducing episomal factors. Subsequent induced pluripotent stem cells were formed into embryoid bodies selective for ectodermal lineage, resulting in neural tube-like rosettes and eventually neural progenitor cells. Differentiation of these precursors into primary neurons was achieved through a regimen of neurotrophic and other factors. These patient-specific primary neurons displayed typical morphology and functionality, also staining positive for mature neuronal markers. The development of such a non-invasive procedure devoid of permanent genetic manipulation during the course of differentiation, in the context of multiple sclerosis, provides an avenue for studies with a greater cell- and human-specific focus, specifically in the context of genetic contributions to neurodegeneration and drug discovery

Schematic overview of methodological procedure.

<p>After isolation and cultivation of RPTECs from urine samples, cells were transfected with pluripotency-inducing genes hOCT3/4, hSK, and hUL, resulting in long-lasting iPSC colonies. Through the cultivation of iPSCs in a free-floating condition, embryoid bodies (EBs) were formed and guided towards ectodermal lineage by addition of SB431542 (SB) and dorsomorphin for the suppression of the meso-, ento-, and epidermal lineages. Maturations of these cell aggregations with EGF and FGF under adherent conditions resulted in neural rosette formations, which were subsequently excised and dissociated into neural progenitor cells (NPCs). These cells were then differentiated to primary neurons (PNs) via basal medium with Sonic hedgehog (Shh) and retinoic acid (RA); cultures were further cultivated through the addition of BDNF and GDNF.</p

Primary antibody list and specifications.

<p>Primary antibody list and specifications.</p

Electrophysiology of MSiPNs.

<p>(A) Representative photomicrograph of an MSiPN while advancing the recording pipette. Independent from the mode of culturing, examined cells were characterized by a pyramidal shaped soma and multipolar dendrite formations. (B) AP firing induced in MSiPNs by increasing depolarizing current injections. (C) Voltage dependence of steady state and fast inward currents recorded in cells derived from a healthy control (HC; 5 cells analyzed) and a MS patient (MS; 5 cells analyzed). (D) Isolated fast inward sodium currents in both MS- and HCiPNs are abolished by TTX bath (10 μM). (E) Representative MSiPN responses to TTX-block of sodium currents to depolarizing voltage steps and of (F) action potentials elicited by current injections.</p

Examples of key stages in neuronal differentiation from epithelial cells.

<p>(A) Male patient RPTECs were photographed after 22 days <i>in vitro</i> and subsequently transfected; scale bar 500 μm. Arrows indicate distinct morphologies as previously reported [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0155274#pone.0155274.ref008" target="_blank">8</a>]. (B) First fully-formed colonies were visualized and cut 21 days after transfection; scale bar 500 μm. Inset shows isolated colony at passage 19; scale bar 375 μm. (C) Cultured EBs were obtained from iPSCs after 4 passages; scale bar 200 μm. (D) Large neural rosettes were photographed and subsequently mechanically isolated 12 days after EB plating; scale bar 200 μm. (E) Cut rosettes underwent trypsinization to form a single-cell suspension of NPCs. Image shows NPCs 8 days after single-cell plating; scale bar 100 μm. (F) Induced primary neurons demonstrates typical neuron morphology, including pyramidal somata (indicated by arrows), extended axons, and formation of neural networks 21 days after switch to differentiation medium; scale bar 200 μm. Inset shows enlarged example of pyramidal morphology; scale bar 100 μm.</p