Faculty Bibliography

Differential mRNA translation efficiency (mTE) of codons is important in regulating protein synthesis and cellular states and can change in response to amino acid availability. While the mTE of codons is canonically associated with their corresponding transfer RNA (tRNA) isoacceptors, its regulation by amino acids in mammalian cells remains unexplored. We found that ELAC2, a 3' tRNA maturation endonuclease, decreases the mTE of UC[C/U] serine (Ser) codons in response to Ser limitation. Ablation of ELAC2 restored UC[C/U] mTE but reduced the mTE of AG[U/C] Ser codons. Among the tRNA^Ser isoacceptors, tRNA^Ser(GCU) decreased the most in ELAC2-deficient cells. Unexpectedly, tRNA^Ser(GCU) delivery restored AG[U/C] mTE and reduced UC[C/U] mTE in ELAC2-deficient cells. Last, we deciphered the effects of Ser-sensitive codons on mRNA translation and the human proteome. Our study revealed that in response to Ser limitation, regulation of tRNA^Ser(GCU) levels fine-tune the mTE of UC[C/U] or AG[U/C] Ser-sensitive codons and shapes the proteome.

Huntington's disease (HD) is a rare, neurodegenerative disorder for which only symptomatic treatments are available. The PROOF-HD study was a randomized, double-blind, placebo-controlled phase 3 trial evaluating the efficacy and safety of pridopidine, a selective Sigma-1 receptor agonist, in HD. The primary and key secondary endpoints, change in total functional capacity (TFC) and composite Unified Huntington's Disease Rating Scale (cUHDRS) score at week 65, were not met in the overall population. The TFC least-squares mean difference between pridopidine and placebo was -0.18 (95% confidence interval -0.49 to 0.14; P = 0.26). The cUHDRS least-squares mean difference between pridopidine and placebo was -0.11 (95% confidence interval -0.40 to 0.18; P = 0.45). Sensitivity analysis in a subgroup of participants not treated with antidopaminergic medications at any time demonstrated a consistent pattern favoring pridopidine across multiple measures, including TFC and cUHDRS. Notably, pridopidine 45 mg twice daily demonstrated a favorable safety and tolerability profile. Taken together, pridopidine has the potential to address a critical unmet need in HD. ClinicalTrials.gov identifier: NCT04556656 .

IntroductionTraumatic intracranial aneurysms (TICAs) are rare, potentially fatal complications of traumatic brain injury (TBI) or iatrogenic insult. Often forming as pseudoaneurysms, TICAs result from direct arterial wall disruption. Their unique pathophysiology, delayed presentation, and high rupture risk pose diagnostic and therapeutic challenges. This review synthesizes current evidence on TICA pathogenesis, diagnosis, and treatment, with particular emphasis on the evolving role of angiographic diagnosis and endovascular intervention.MethodsA structured PubMed search was conducted, supplemented by manual citation screening. All study designs were considered with no date restrictions. Articles were included if they reported traumatic intracranial aneurysms in patients of any age and discussed diagnostic or therapeutic approaches. Data were synthesized thematically across epidemiology, pathophysiology, imaging, treatment (endovascular and surgical), and surveillance.ResultsTICAs typically arise at sites of direct injury or at fixed vessel segments (e.g., distal ACA, peripheral MCA, cavernous/supraclinoid ICA). Their delayed and subtle appearance necessitates high clinical suspicion and serial imaging. Digital subtraction angiography is the diagnostic gold standard, though immediate or early post-trauma studies may be negative. Endovascular techniques, particularly flow diversion, are increasingly favored for their minimally invasive nature and ability to achieve parent vessel reconstruction. Open surgery retains a role for lesions complicated by mass effect, intracerebral hematoma, or anatomy unsuitable for endovascular repair. Outcomes vary with aneurysm location, treatment timing, modality, and TBI severity.ConclusionTICAs represent a distinct, high-risk entity requiring timely diagnosis and individualized, multidisciplinary management. Endovascular approaches are increasingly favored. Further research is needed to guide optimal surveillance imaging protocols.

Monitoring representative fractions of neurons from multiple brain circuits in behaving animals is necessary for understanding how different brain regions interact. Using multishank, high-density recording silicon probes (up to 1,024 sites), we describe the main characteristic LFP patterns in the hippocampus, including sharp wave-ripples (SPW-Rs), dentate spikes (DSs), theta, and gamma oscillations. Our novel observations primarily relate to the distinction between subclasses of SPW-Rs and DSs, as well as their neuronal spiking correlations. In addition to the classical SPW-Rs, initiated in the CA2-3 recurrent collateral system and characterized by a large negative sharp wave (sink) in the mid-CA1 stratum radiatum (SPW-R^Rad), a small subset of ripples, associated with a sink in CA1 str. lacunosum-moleculare was also observed (SPW-R^LM). The two types of ripple events differed in frequency, magnitude, and neuronal correlates. CA3 pyramidal neurons were strongly active during SPW-R^Rad but not during (SPW-R^LM). DSs could also be grouped further based on their excitatory inputs from the medial and lateral entorhinal cortex (DS^MEC and DS^LEC), by their impact on their physiological targets, and by the brain states into which they were embedded. Overall, our experiments demonstrate the utility and need for high-density recording of both LFP and spiking activity for the appropriate classification of seemingly similar events. These distinctions relate not only to their neurogenesis but also to their behavioral-cognitive contributions.

Understanding consciousness remains a significant challenge in science. What distinguishes conscious beings from unconscious systems, such as organoids, artificial intelligence or other non-sentient entities? Research on consciousness often focuses on identifying brain activity associated with conscious and non-conscious states, primarily in neurotypical human adults. However, this approach is limited in scope when applied to entities with developmental or evolutionary trajectories different from our own. How do we investigate consciousness in infants, whose brains are still maturing or in non-human animals, shaped by diverse ecological and evolutionary pressures? This opinion piece encourages consciousness studies to adopt a neuroethological perspective, drawing on Tinbergen's framework for studying behaviour. By examining the (1) mechanisms, (2) development, (3) adaptive functions and (4) evolutionary origins of consciousness, we can move beyond a human-centric focus to explore its diversity across life forms. Most investigators now accept that consciousness is not confined to humans alone but that some other animals have it, and it is a continuum shaped by evolutionary pressures. By adopting this broader approach, consciousness studies can better investigate and understand consciousness in its various forms and contexts, with significant scientific, ethical and societal implications.This article is part of the theme issue 'Evolutionary functions of consciousness'.

BACKGROUND:CDKL5 deficiency disorder (CDD) is a rare developmental and epileptic encephalopathy (DEE) associated with multiple impairments and comorbidities. Outcome measures for disease-modifying clinical trials for DEEs should measurably capture a spectrum of caregiver priorities and be externally validated. METHODS:The International CDKL5 Clinical Research Network was the data source for this observational study. A Structural Equation Model was constructed with latent, exogenous variables related to observed clinical features to calculate a global severity score from the following assessments: the CDKL5 Clinical Severity Assessment-Clinician and -Caregiver, Communication and Symbolic Behavior Scales Developmental Profile Infant Toddler Checklist and the Sleep Disturbance Scale for Children. Quantitative EEG power was measured as a biomarker. The Quality of Life Inventory-Disability measured quality of life. RESULTS:Acceptable fit statistics for models were obtained using data from 206 subjects (median [range] age 6.8 [3 months to 40] years). Motor and communication measures were the most important weighted contributors to the global severity score which correlated well with the biomarker and quality of life to support external validation. CONCLUSIONS:The resultant global severity score provided evidence that the assessments formed a coherent set of measures that reliably and meaningfully captured the diversity of severity in CDD. The models illustrated how the symptoms form a measurable network of relationships which may be suitable as an outcome measure for CDD and DEEs more broadly in clinical trials.

INTRODUCTION/BACKGROUND:The Neighborhoods Study (TNS) is a novel investigation of adverse social exposome and brain health leveraging 22 Alzheimer's Disease Research Centers (ADRCs). TNS aims to understand if the adverse social exposures increase Alzheimer's disease and related dementias (ADRD) risk. METHODS:TNS uses innovative methods to determine lifetime addresses of living (n = ≈ 3116) and brain bank cohorts (n = ≈ 8637). Addresses are linked to time-concordant adverse social exposome using the Area Deprivation Index (ADI) and summarized over time. Brain health measures are provided by the National Alzheimer's Coordinating Center. RESULTS:We highlight a general overview and methodology of TNS. Data collection is ongoing; however, preliminary findings indicate that the adverse social exposome is related to ADRD biomarkers, neuropathology, and cognitive function. DISCUSSION/CONCLUSIONS:TNS is the largest study of adverse social exposome and ADRD, using the ADRC network to build robust scientific consortia. Its findings will inform ADRD interventions, precision medicine, and policy. HIGHLIGHTS/CONCLUSIONS:The Neighborhoods Study (TNS) investigates adverse social exposome and brain health. TNS is a collaboration among 22 Alzheimer's Disease Research Centers. TNS will give insight on environmental and exposomal factors which may be modifiable. Participant lifetime addresses are linked to temporal adverse social exposome metrics. This study's findings will inform precision approaches to mitigate dementia risk.