Faculty Bibliography

KdpFABC is an ATP-dependent membrane complex that enables prokaryotes to maintain potassium homeostasis under potassium-limited conditions. It features a unique hybrid mechanism combining a channel-like selectivity filter in KdpA with the ATP-driven transport functionality of KdpB. A key unresolved question is whether K+ ions translocate through the inter-subunit tunnel as a queue of ions or individually within a hydrated environment. Using molecular dynamics simulations, metadynamics, anomalous X-ray scattering, and biochemical assays, we demonstrate that the tunnel is predominantly occupied by water molecules rather than multiple K+ ions. Our results identify only one stable intermediate binding site for K+ within the tunnel, apart from the canonical sites in KdpA and KdpB. Free energy calculations reveal a substantial barrier (∼22 kcal/mol) at the KdpA-KdpB interface, making spontaneous K+ translocation unlikely. Furthermore, mutagenesis and functional assays confirm previous findings that Phe232 at this interface plays a key role in coupling ATP hydrolysis to K+ transport. These findings challenge previous models containing a continuous wire of K+ ions through the tunnel and suggest the existence of an as-yet unidentified intermediate state or mechanistic detail that facilitates K+ movement into KdpB.

The discovery of non-coding RNAs has expanded our understanding of how genetic features are linked to cellular function. The illumination of this so-called dark matter of the genome has revealed new categories of RNA with essential roles in the regulation of protein-coding genes and genome organization. In particular, microRNAs and long non-coding RNAs have emerged as important regulators of cardiovascular health and disease. In this Review, we summarize our current understanding of the mechanisms and functional roles of microRNAs and long non-coding RNAs in the regulation of lipid homeostasis, vascular biology and atherosclerosis. We discuss how interruption of non-coding RNA regulatory circuits influence lipoprotein metabolism in the liver and the circulation, as well as the effects of non-coding RNAs on inflammatory processes in the artery wall that contribute to atherosclerotic plaque formation. Finally, we highlight potential opportunities to harness non-coding RNAs as biomarkers and targeted therapeutics for atherosclerotic cardiovascular disease.

The narrowest biological tubes are comprised of cells that hollow to form an intracellular lumen. Here, we examine early lumenogenesis of the C. elegans excretory cell, which branches to form an H-shaped intracellular tube spanning the length of the worm. Using genetically paralyzed embryos to freeze movement, we describe lumen initiation and branching for the first time using time-lapse fluorescence microscopy. We show that the excretory cell lumen forms through a plasma membrane invasion mechanism when a nascent lumen grows from the plasma membrane into the cytoplasm. The lumen subsequently extends along the left-right axis before branching to form anterior-posterior projections. Through a genetic screen, we identify mutations in ina-1/⍺-integrin and pat-3/β-integrin that block lumenogenesis at the anterior-posterior branching step, and we show that integrin function is required within the excretory cell. Finally, we find that the excretory cell crosses the epidermal basement membrane where anterior-posterior branches form and demonstrate that basement membrane crossing fails in integrin mutant embryos. Our findings reveal how an intracellular lumen initiates and branches and identify integrins and basement membrane as key branching regulators.

BACKGROUND:Intestinal ultrasonography (IUS) is increasingly utilised for diagnosing and monitoring IBD. Despite its cost-effectiveness, patient tolerance and suitability for serial bedside assessments, broad adoption has been limited by knowledge gaps in evidence, training and standardisation. AIMS/OBJECTIVE:To summarise key knowledge gaps in the assessment of luminal disease activity, postoperative recurrence, complications, pouch-related disorders and the use of IUS in paediatrics, contrast enhancement, elastography, as well as education, training and future applications involving artificial intelligence. METHODS:We conducted a systematic umbrella review, following PRISMA guidelines, to map the current landscape of high-quality evidence and identify gaps in IUS research relevant to IBD. We searched MEDLINE from inception to February 2025 for systematic reviews, meta-analyses and consensus statements. We extracted data from eligible studies on design, outcomes and identified research gaps. Gaps were categorised by insufficient information, bias, inconsistency or lack of relevant data. RESULTS:Sixty of 507 studies met inclusion criteria. Key gaps included lack of validated and standardised IUS activity indices for Crohn's disease and ulcerative colitis, limited evidence for IUS in post-operative recurrence, paediatric populations and perianal or pouch disease. Data on the use of contrast-enhanced ultrasound and elastography were sparse. Small sample sizes, heterogeneous designs and inadequate follow-up limited most studies. Training, competency assessment and integration of artificial intelligence remain underexplored. CONCLUSIONS:Sizable gaps persist in the evidence base for IUS in IBD. Addressing these gaps through robust, multicentre studies and consensus-driven frameworks is essential to optimise the clinical and research utility of IUS in IBD management.

The science of metabolic profiling exploits chemical compound byproducts of metabolism called metabolites¹ that explain internal biological functions, physiological health and disease, and provide evidence of external influences specific to an organism's habitat. Here we assess palaeometabolomes from fossilized mammalian hard tissues as a molecular ecological strategy to provide evidence of an ancient organism's relationship with its environment. From eastern, central and southern African Plio-Pleistocene localities of palaeoanthropological significance, we study six fossils from Olduvai Gorge, Tanzania, one from the Chiwondo Beds, Malawi, and one from Makapansgat, South Africa. We perform endogeneity assessments by analysing palaeometabolomes of palaeosols and the effects of owl digestion on rodent bones to enable prudent ecological inferences. Diagenesis is indicated by metabolites of collagenase-producing bacteria², whereas the preservation of peptides including those of collagen are identified by proteomics. Endogenous metabolites document biological functions and exogenous metabolites render environmental details including soil characteristics and woody cover, and enable annual minimum and maximum rainfall and temperature reconstructions at Olduvai Gorge, supporting the freshwater woodland and grasslands of Olduvai Gorge Bed I^3-5, and the dry woodlands and marsh of Olduvai Gorge Upper Bed II⁶. All sites denote wetter and/or warmer conditions than today. We infer that metabolites preserved in hard tissues derive from an extravasated vasculature serum filtrate that becomes entombed within developing mineralized matrices, and most probably survive palaeontological timeframes in the nanoscopic 'pool' of structural-bound water that occurs in hard tissue niches⁷.

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.

Vascularized composite allotransplantation (VCA) involves immunologically heterogeneous tissues with a high incidence of acute rejection. Reliable and timely detection of rejection onset remains a major unmet challenge in VCA management. This longitudinal exploratory case study assessed blood- and tissue-derived biomarkers for acute rejection monitoring in a full-face and bilateral hand transplant recipient over 4.6 years. Of these biomarkers, donor-derived cell-free DNA (dd-cfDNA) and short tandem repeats (STR) showed trends toward elevated recipient levels during acute rejection, though differences were not statistically significant. CD8⁺ T-cell percentages increased before acute rejection onset, highlighting a temporal association. Anti-angiotensin II type 1 receptor antibody (AT1R-Ab) levels did not differ significantly between acute rejection and non-rejection episodes, possibly due to prophylactic immune cell depletion. While dd-cfDNA and STR levels correlate with rejection episodes and reflect key graft cellular events, CD8⁺ T-cell dynamics demonstrated the strongest temporal association with rejection episodes in this patient, though no biomarker showed statistically significant differences. These exploratory findings support the need for further longitudinal, multi-patient studies to validate emerging biomarkers and refine rejection monitoring strategies in VCA.

For many rare diseases with no approved preventive interventions, promising interventions exist. However, it has proven difficult to conduct a pivotal phase 3 trial that could provide direct evidence demonstrating a beneficial effect of the intervention on the target disease outcome. When a promising putative surrogate endpoint(s) for the target outcome is available, surrogate-based provisional approval of an intervention may be pursued. Following the general Causal Roadmap rubric, we describe a surrogate endpoint-based provisional approval causal roadmap. Based on an observational study data set and a phase 3 randomized trial data set, this roadmap defines an approach to analyze the combined data set to draw a conservative inference about the treatment effect (TE) on the target outcome in the phase 3 study population. The observational study enrolls untreated individuals and collects baseline covariates, surrogate endpoints, and the target outcome, and is used to estimate the surrogate index-the regression of the target outcome on the surrogate endpoints and baseline covariates. The phase 3 trial randomizes participants to treated vs. untreated and collects the same data but is much smaller and hence very underpowered to directly assess TE, such that inference on TE is based on the surrogate index. This inference is made conservative by specifying 2 bias functions: one that expresses an imperfection of the surrogate index as a surrogate endpoint in the phase 3 study, and the other that expresses imperfect transport of the surrogate index in the untreated from the observational to the phase 3 study. Plug-in and nonparametric efficient one-step estimators of TE, with inferential procedures, are developed. The finite-sample performance of the estimators is evaluated in simulation studies. The causal roadmap is motivated by and illustrated with contemporary Group B Streptococcus vaccine development.