Centrioles are cylindrical structures that are usually composed of nine triplets of microtubules (MTs) organized around a cartwheel‐shaped structure. Recent studies have proposed a structural model ...of the SAS‐6‐based cartwheel, yet we do not know the molecular detail of how the cartwheel participates in centriolar MT assembly. In this study, we demonstrate that the human microcephaly protein, CEP135, directly interacts with hSAS‐6 via its carboxyl‐terminus and with MTs via its amino‐terminus. Unexpectedly, CEP135 also interacts with another microcephaly protein CPAP via its amino terminal domain. Depletion of CEP135 not only perturbed the centriolar localization of CPAP, but also blocked CPAP‐induced centriole elongation. Furthermore, CEP135 depletion led to abnormal centriole structures with altered numbers of MT triplets and shorter centrioles. Overexpression of a CEP135 mutant lacking the proper interaction with hSAS‐6 had a dominant‐negative effect on centriole assembly. We propose that CEP135 may serve as a linker protein that directly connects the central hub protein, hSAS‐6, to the outer MTs, and suggest that this interaction stabilizes the proper cartwheel structure for further CPAP‐mediated centriole elongation.
Different organism‐dependent centriole biogenesis roles have been suggested for CEP135/Bld10. Analysis of the human homologue CEP135/MCPH8 supports a key role in connecting the centriolar cartwheel hub SAS‐6, the elongation factor CPAP, and outer microtubules.
Cancer is influenced by its microenvironment, yet broader, environmental effects also play a role but remain poorly defined. We report here that mice living in an enriched housing environment show ...reduced tumor growth and increased remission. We found this effect in melanoma and colon cancer models, and that it was not caused by physical activity alone. Serum from animals held in an enriched environment (EE) inhibited cancer proliferation in vitro and was markedly lower in leptin. Hypothalamic brain-derived neurotrophic factor (BDNF) was selectively upregulated by EE, and its genetic overexpression reduced tumor burden, whereas BDNF knockdown blocked the effect of EE. Mechanistically, we show that hypothalamic BDNF downregulated leptin production in adipocytes via sympathoneural β-adrenergic signaling. These results suggest that genetic or environmental activation of this BDNF/leptin axis may have therapeutic significance for cancer.
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► Mice housed in an enriched environment (EE) show decreased cancer growth and remission ► EE stimulates the expression of BDNF within the hypothalamus ► BDNF, via a sympatho-adipocyte axis, shuts down the fat hormone leptin ► The suppression of leptin mediates the anticancer effects
POMC-derived melanocortins inhibit food intake. In the adult rodent brain, POMC-expressing neurons are located in the arcuate nucleus (ARC) and the nucleus tractus solitarius (NTS), but it remains ...unclear how POMC neurons in these two brain nuclei regulate feeding behavior and metabolism differentially. Using pharmacogenetic methods to activate or deplete neuron groups in separate brain areas, in the present study, we show that POMC neurons in the ARC and NTS suppress feeding behavior at different time scales. Neurons were activated using the DREADD (designer receptors exclusively activated by designer drugs) method. The evolved human M3-muscarinic receptor was expressed in a selective population of POMC neurons by stereotaxic infusion of Cre-recombinase-dependent, adeno-associated virus vectors into the ARC or NTS of POMC-Cre mice. After injection of the human M3-muscarinic receptor ligand clozapine-N-oxide (1 mg/kg, i.p.), acute activation of NTS POMC neurons produced an immediate inhibition of feeding behavior. In contrast, chronic stimulation was required for ARC POMC neurons to suppress food intake. Using adeno-associated virus delivery of the diphtheria toxin receptor gene, we found that diphtheria toxin-induced ablation of POMC neurons in the ARC but not the NTS, increased food intake, reduced energy expenditure, and ultimately resulted in obesity and metabolic and endocrine disorders. Our results reveal different behavioral functions of POMC neurons in the ARC and NTS, suggesting that POMC neurons regulate feeding and energy homeostasis by integrating long-term adiposity signals from the hypothalamus and short-term satiety signals from the brainstem.
In addition to the classical neurotransmitters, neuropeptides represent an important class of modulators for affective behaviors and associated disorders, such as anxiety disorders. Many ...neuropeptides are abundantly expressed in brain regions involved in emotional processing and anxiety behaviors. Moreover, risk factors for anxiety disorders such as stress modulate the expression of various neuropeptides in the brain. Due to the high prevalence of anxiety disorders and yet limited treatment options, there is a clear need for more effective therapeutics. In this regard, the various neuropeptides represent exciting candidates for new therapeutic designs. In this review, I will provide an up-to-date summary on the evidences for the involvement of seven neuropeptides in anxiety: corticotropin-releasing factor, urocortins, vasopressin, oxytocin, substance P, neuropeptide Y and galanin. This review will cover the behavioral effects of these neuropeptides in animal models of anxiety by both genetic and pharmacological manipulations. Human studies indicating a role for these neuropeptides in anxiety disorders will also be discussed.
Changes in whole body energy levels are closely linked to alterations in body weight and bone mass. Here, we show that hypothalamic signals contribute to the regulation of bone mass in a manner ...consistent with the central perception of energy status. Mice lacking neuropeptide Y (NPY), a well-known orexigenic factor whose hypothalamic expression is increased in fasting, have significantly increased bone mass in association with enhanced osteoblast activity and elevated expression of bone osteogenic transcription factors, Runx2 and Osterix. In contrast, wild type and NPY knockout (NPY (-/-)) mice in which NPY is specifically over expressed in the hypothalamus (AAV-NPY+) show a significant reduction in bone mass despite developing an obese phenotype. The AAV-NPY+ induced loss of bone mass is consistent with models known to mimic the central effects of fasting, which also show increased hypothalamic NPY levels. Thus these data indicate that, in addition to well characterized responses to body mass, skeletal tissue also responds to the perception of nutritional status by the hypothalamus independently of body weight. In addition, the reduction in bone mass by AAV NPY+ administration does not completely correct the high bone mass phenotype of NPY (-/-) mice, indicating the possibility that peripheral NPY may also be an important regulator of bone mass. Indeed, we demonstrate the expression of NPY specifically in osteoblasts. In conclusion, these data identifies NPY as a critical integrator of bone homeostatic signals; increasing bone mass during times of obesity when hypothalamic NPY expression levels are low and reducing bone formation to conserve energy under 'starving' conditions, when hypothalamic NPY expression levels are high.
Purpose
Social determinants of health (SDOH) significantly impact individuals’ engagement with the healthcare system. To address SDOH‐related oral health disparities, providers must be equipped with ...knowledge, skills, and attitudes (KSAs) to understand how SDOH affect patients and how to mitigate these effects. Traditional dental school curricula provide limited training on recognizing SDOH or developing empathy for those with SDOH‐related access barriers. This study describes the design and evaluation of such a virtual reality (VR)‐based simulation in dental training. We hypothesize the simulation will increase post‐training KSAs.
Methods
We developed “MPATHI” (Making Professionals Able THrough Immersion), a scripted VR simulation where participants take the role of an English‐speaking caregiver with limited socioeconomic resources seeking dental care for a child in a Spanish‐speaking country. The simulation is a combination of 360° video recording and virtual scenes delivered via VR headsets. A pilot was conducted with 29 dental
residents/faculty, utilizing a pre‐post design to evaluate effectiveness in improving immediate and retention of KSAs toward care delivery for families facing barriers.
Results
MPATHI led to increased mean scores for cognitive (pre = 3.48 ± 0.80, post = 4.56 ± 0.51, p < 0.001), affective (pre = 4.20 ± 0.4, post = 4.47 ± 0.44, p < 0.001), and skill‐based learning (pre = 4.00 ± 0.47, post = 4.52 ± 0.37, p < 0.001) immediately post‐training. There was not a significant difference between skills measured immediately post‐training and in the 1‐month post‐training survey (p = 0.41). Participants reported high satisfaction with the content and methods used in this training.
Conclusions
This pilot study supports using VR SDOH training in dental education. VR technology provides new opportunities for innovative content design.
Post-translational modifications (PTMs), such as glycosylation and palmitoylation, are critical to protein folding, stability, intracellular trafficking, and function. Understanding regulation of ...PTMs of SARS-CoV-2 spike (S) protein could help the therapeutic drug design. Herein, the VSV vector was used to produce SARS-CoV-2 S pseudoviruses to examine the roles of the 611LYQD614 and cysteine-rich motifs in S protein maturation and virus infectivity. Our results show that 611LY612 mutation alters S protein intracellular trafficking and reduces cell surface expression level. It also changes S protein glycosylation pattern and decreases pseudovirus infectivity. The S protein contains four cysteine-rich clusters with clusters I and II as the main palmitoylation sites. Mutations of clusters I and II disrupt S protein trafficking from ER-to-Golgi, suppress pseudovirus production, and reduce spike-mediated membrane fusion activity. Taken together, glycosylation and palmitoylation orchestrate the S protein maturation processing and are critical for S protein-mediated membrane fusion and infection.
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•611LY612 mutation alters the glycosylation pattern of the SARS-CoV-2 S protein•611LY612 mutation reduces S protein surface expression level•Palmitoylation targets mature S protein to the Golgi and plasma membrane•Palmitoylation is required for pseudovirus and SARS-CoV-2 production
Biochemistry; Virology; Cell biology.
Pancreatic polypeptide (PP) is a potent anti-obesity agent known to inhibit food intake in the absence of nausea, but the mechanism behind this process is unknown.
Here we demonstrate that in ...response to i.p. injection of PP in wild type but not in Y4 receptor knockout mice, immunostaining for the neuronal activation marker c-Fos is induced specifically in neurons of the nucleus tractus solitarius and the area postrema in the brainstem, notably in cells also showing immunostaining for tyrosine hydroxylase. Importantly, strong c-Fos activation is also detected in the arcuate nucleus of the hypothalamus (ARC), particularly in neurons that co-express alpha melanocyte stimulating hormone (alpha-MSH), the anorexigenic product of the proopiomelanocortin (POMC) gene. Interestingly, other hypothalamic regions such as the paraventricular nucleus, the ventromedial nucleus and the lateral hypothalamic area also show c-Fos induction after PP injection. In addition to c-Fos activation, PP injection up-regulates POMC mRNA expression in the ARC as detected by in situ hybridization. These effects are a direct consequence of local Y4 signaling, since hypothalamus-specific conditional Y4 receptor knockout abolishes PP-induced ARC c-Fos activation and blocks the PP-induced increase in POMC mRNA expression. Additionally, the hypophagic effect of i.p. PP seen in wild type mice is completely absent in melanocortin 4 receptor knockout mice.
Taken together, these findings show that PP reduces food intake predominantly via stimulation of the anorexigenic alpha-MSH signaling pathway, and that this effect is mediated by direct action on local Y4 receptors within the ARC, highlighting a potential novel avenue for the treatment of obesity.
Hypothalamic brain-derived neurotrophic factor (BDNF) is a key element in the regulation of energy balance. Here we investigated the therapeutic efficacy of BDNF by gene transfer in mouse models of ...obesity and diabetes. Gene transfer of BDNF led to marked weight loss and alleviation of obesity-associated insulin resistance. To facilitate clinical translation and ensure that BDNF protein expression was appropriately decreased as weight loss progressed, thus preventing cachexia, we developed a molecular autoregulatory system involving a single recombinant adeno-associated virus vector harboring two expression cassettes, one constitutively driving BDNF and the other driving a specific microRNA targeting BDNF. The microRNA element was controlled by a promoter (that controlling the Agrp gene encoding agouti-related peptide) responsive to BDNF-induced physiological changes. Hence, as body weight decreased and agouti-related protein is induced, microRNA expression was activated, inhibiting transgene expression. In contrast to the progressive weight loss associated with a nonregulated approach, this microRNA-approach led to a sustainable plateau of body weight after notable weight loss was achieved. This strategy mimics the body's endogenous physiological feedback mechanisms, thereby resetting the hypothalamic set point to reverse obesity and metabolic syndrome.
The importance of neuropeptide Y (NPY) and Y2 receptors in the regulation of bone and energy homeostasis has recently been demonstrated. However, the contributions of the other Y receptors are less ...clear. Here we show that Y1 receptors are expressed on osteoblastic cells. Moreover, bone and adipose tissue mass are elevated in Y1-/- mice with a generalized increase in bone formation on cortical and cancellous surfaces. Importantly, the inhibitory effects of NPY on bone marrow stromal cells in vitro are absent in cells derived from Y1-/- mice, indicating a direct action of NPY on bone cells via this Y receptor. Interestingly, in contrast to Y2 receptor or germ line Y1 receptor deletion, conditional deletion of hypothalamic Y1 receptors in adult mice did not alter bone homeostasis, food intake, or adiposity. Furthermore, deletion of both Y1 and Y2 receptors did not produce additive effects in bone or adiposity. Thus Y1 receptor pathways act powerfully to inhibit bone production and adiposity by nonhypothalamic pathways, with potentially direct effects on bone tissue through a single pathway with Y2 receptors.
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