Faculty Bibliography

The current generation of highly successful atherosclerosis treatments, such as low-density lipoprotein (LDL)-cholesterol reduction, blood pressure management, and smoking cessation, has largely focused on ameliorating factors perceived to drive incident disease and its complications. The adverse contributions of these factors have typically been identified through epidemiological studies. The therapeutic strategies that arose in response focused on risk factors for disease development and tended to overlook the fact that patients already have established disease, by the time of presentation. However, by capitalizing on contemporary biological knowledge and technologies, it is becoming increasingly possible to shift from a model based on population-derived risk factor management to next-generation treatments (including monoclonal antibodies, small interfering RNA [siRNA], mRNA, epigenetic reprogramming, and gene editing) for atherosclerosis that are tailored to patient-level disease processes, informed by mechanistic characterization, offer potential to reverse or regress disease, and incorporate systems-level interventions that extend beyond the atherosclerotic plaque.

BACKGROUND:Motor stereotypies (MS) represent one of the transdiagnostic symptom dimensions identified by the NIMH Research Domain Criteria work group as relevant to psychopathology. MS are common in neurodevelopmental conditions, but they remain poorly understood, particularly in early childhood. The present study examined MS in 648 toddlers with autism spectrum disorder (autism, n = 455) and other neurodevelopmental conditions (non-autism, n = 193) and their concurrent and prospective links with other phenotypic characteristics. METHODS:Toddlers were recruited between February 2000 and October 2018 and evaluated at 24 +/- 5 months (Time 1, N = 648) and 41 +/- 6 months (Time 2, N = 455). The presence of MS was determined based on the Autism Diagnostic Observation Schedule assessment. The phenotypic measures included adaptive socialization skills, severity of social symptoms of autism, and verbal, nonverbal, and motor skills. The analysis was conducted using the general linear models while controlling for age, sex, visit year, group, and other relevant covariates. RESULTS: CONCLUSIONS:Motor stereotypies are present in toddlers with and without autism and may represent a distinct transdiagnostic dimension expressed early in development, associated with core developmental skills and, putatively, characterized by shared pathophysiology across neurodevelopmental conditions.

Ribosomes are central to protein synthesis in all organisms. Among mammals, the ribosome functional core is highly conserved. Remarkably, two rodent species, the naked mole-rat (NMR) and tuco-tuco display fragmented 28S rRNA, coupled with high translational fidelity and long lifespan. The unusual ribosomal architecture in the NMR and tuco-tuco has been speculated to be linked to high translational fidelity. Here we show, by single-particle cryo-electron microscopy (cryo-EM), that despite the fragmentation of their rRNA, NMR and tuco-tuco ribosomes retain their core functional architecture. Compared to ribosomes of the guinea pig, a phylogenetically related rodent without 28S rRNA fragmentation, ribosomes of NMR and tuco-tuco exhibit poorly resolved, certain expansion segments. In contrast, the structure of the guinea pig ribosome shows high similarity to human ribosome. Enhanced translational fidelity in the NMR and tuco-tuco may stem from subtle, allosteric effects in dynamics, linked to rRNA fragmentation.

OBJECTIVE:This study examined racial and ethnic differences in percent total weight loss (%TWL) and glycemic improvement following sleeve gastrectomy (SG) and explored the role of socioeconomic and psychosocial factors in postsurgical outcomes. METHODS:This longitudinal study included patients who underwent SG between 2017 and 2020, with follow-up visits over 24 months. RESULTS:Non-Hispanic Black (NHB) participants had lower %TWL at 3, 12, and 24 months compared with Hispanic (H) and non-Hispanic White (NHW) participants. Fat mass index was initially lower in NHB, with smaller reductions over time and significant group differences persisting at 24 months. NHB participants had higher baseline fat-free mass index values; by 24 months, fat-free mass index values were lower in H participants. Hemoglobin A1c decreased across all groups but remained consistently higher in NHB and H compared with NHW at 24 months. NHB participants reported higher perceived discrimination, sleep disturbance, and perceived stress than H and NHW participants at all time points. Employment status predicted %TWL at 12 months. There was a significant interaction between race and ethnicity and employment status observed at 12 and 24 months, suggesting that employment-related disparities could impact surgical outcomes. CONCLUSIONS:NHB participants experienced less favorable outcomes following SG, emphasizing the need for tailored interventions addressing socioeconomic and psychosocial disparities.

Auxins are plant hormones that direct the growth and development of organisms on the basis of environmental cues. Indole-3-acetic acid (IAA) is the most abundant auxin in most plants. A variety of membrane transport proteins work together to distribute auxins. These include the AUX/LAX protein family that mediate auxin import from the apoplast to the cytosol. Here we use structural and biophysical approaches combined with molecular dynamics to study transport by Arabidopsis thaliana LAX3, which is essential for plant root formation. Transport assays document high-affinity transport of IAA, as well as competitive behaviour of the synthetic phenoxyacetic acid auxin herbicide 2,4-dichlorophenoxyacetic acid and the auxin transport inhibitors 1-naphthoxyacetic acid and 2-naphthoxyacetic acid. Four cryo-EM structures were solved with resolutions of 2.9-3.4 Å: an inward open apo structure, two inward semi-occluded structures in complex with IAA and 2,4-dichlorophenoxyacetic acid, and a fully occluded structure in complex with 2-naphthoxyacetic acid. Structurally, LAX3 consists of a bundle and a scaffold domain. The ligand-binding site is sandwiched between these domains with two histidines occupying positions analogous to the sodium-binding sites in distantly related sodium:neurotransmitter transporters. This architecture suggests that these histidines couple transport to the proton motive force. Molecular dynamics simulations are used to explore substrate binding and release, including their dependence on specific protonation states. This study advances our understanding of auxin recognition and transport by AUX/LAX, providing insights into a fundamental aspect of plant physiology and development.

BACKGROUND:Patients with peripheral artery disease have an increased risk of cancer development. Aging-associated changes in hematopoietic stem and progenitor cells (HSPCs), including inflammation and increased myelopoiesis, are implicated in both cardiovascular disease and cancer, but their contributions to cardiovascular disease-driven tumor progression are unclear. OBJECTIVES/OBJECTIVE:This study sought to study tumor growth after peripheral ischemia and consequent changes within the HSPC bone marrow compartment to uncover mechanisms through which altered hematopoiesis promotes cancer. METHODS:Mammary cancer (E0771) growth was monitored in C57BL/6J mice after hind limb ischemia (HLI) or sham surgery. The tumor immune microenvironment, circulatory immune cells, and HSPC compartment were assessed by flow cytometry. Next-generation single-cell RNA and assay for transposase-accessible chromatin sequencing of bone marrow progenitors was performed to assess the distinct and synergistic transcriptomic and epigenetic changes of cancer and peripheral ischemia. The functional impact on tumor progression and persistence of ischemia-induced epigenetic reprogramming of HSPCs and their myeloid progeny was examined by bone marrow transplantation. RESULTS:myeloid-biased hematopoietic stem cells. This was associated with accelerated cancer growth and enrichment of tumors with myeloid cells (monocytes, macrophages, neutrophils) and regulatory T cells. Increased myelopoiesis was also supported by sequencing analyses showing HLI and tumor-induced transcriptional and epigenetic enrichment for inflammatory (NLRP3 inflammasome) and aging-associated neogenin-1, thrombospondin-1) signatures in subsets of monocyte/dendritic progenitors. HLI-accelerated tumor growth and myeloid-skewing was transmissible via bone marrow transplantation, indicating long-term reprogramming of innate immune responses. CONCLUSIONS:Peripheral ischemia enhances inflammaging of hematopoietic stem cells and long-lasting alterations to antitumoral immunity, accelerating breast tumor growth.

The mammalian brain is the most cholesterol-rich organ of the body, relying on in situ de novo cholesterol synthesis. Maintaining cholesterol homeostasis is crucial for normal brain function. Oxysterol-binding protein (OSBP)-related proteins (ORPs) are highly conserved cytosolic proteins that coordinate lipid homeostasis by regulating cell signaling, inter-organelle membrane contact sites, and non-vesicular transport of cholesterol. Here, we show that ORP6 is highly enriched in the mammalian brain, particularly within neurons and astrocytes, with widespread expression across distinct brain regions, including the hippocampus, which is essential for learning and memory. Whole-body ablation of ORP6 (Osbpl6^-/-) in mice resulted in dysregulation of systemic and brain lipid homeostasis, with elevated levels of brain desmosterol and amyloid-beta oligomers (AβOs). Mechanistically, ORP6 knockdown in astrocytes altered the expression of cholesterol metabolism genes, promoting the accumulation of esterified cholesterol in lipid droplets, reducing cholesterol efflux and plasma membrane cholesterol content, and increasing amyloid-beta precursor protein (APP) processing. Our findings underscore the role of ORP6 in systemic and brain lipid homeostasis, highlighting its importance in maintaining overall brain health.

BACKGROUND:As the incidence of frontal fibrosing alopecia (FFA) continues to rise, there is a need for an optimal treatment algorithm for FFA. OBJECTIVE:To produce an international consensus statement on the treatment modalities and prognostic indicators of FFA. METHODS:Sixty-nine hair experts from six continents were invited to participate in a three-round Delphi process. The final stage was held as a virtual meeting facilitated via Zoom. The consensus threshold was set at ≥66%. RESULTS:Of 365 questions, expert consensus was achieved in 204 (56%) questions following completion of the three rounds. Three additional questions were included at the final meeting. The category with the strongest consensus agreement was disease monitoring (9; 100%). Questions pertaining to physical therapies achieved the least category consensus (15; 40%), followed by systemic therapy (45; 43%). LIMITATIONS/CONCLUSIONS:The study lacked sufficient representation from Africa and South America. CONCLUSION/CONCLUSIONS:SOFFIA highlights areas of agreement and disagreement among experts. Robust research is warranted to provide evidence-based treatment recommendations.