Research Discoveries in March 2025

Microglia, the resident immune cells of the central nervous system, play a pivotal role in the response to Huntington's disease (HD) pathology. Through both cell-autonomous mechanisms and exposure to external pathogenic stimuli, microglia transition from a resting to an activated state, producing pro-inflammatory cytokines and chemokines that mediate inflammation. While this inflammatory response attempts to have a neuroprotective compensatory effect, chronic microglial activation exacerbates neuroinflammation, neurodegeneration and contributes to disease progression. Evidence from postmortem analyses and neuroimaging studies indicates that activated microglia are present in various stages of HD, correlating with neuronal degeneration and clinical symptoms. Enhanced microglial activation has been identified as an early predictor of disease onset, particularly in premanifest HD, highlighting the potential of targeting microglial pathways for therapeutic interventions. This review explores microglia's dual role in HD pathophysiology, exploring their contributions to both neuroinflammation and neuroprotection. It also examines recent advances in clinical trials aimed at modulating microglial activity, paving the way for novel therapeutic strategies to alter disease progression and improve patient outcomes.

Detection of mitochondria-ER contacts (MERCs) from diffraction limited confocal images commonly uses fluorescence colocalization analysis of mitochondria and endoplasmic reticulum (ER) as well as split fluorescent probes, such as the split-GFP-based contact site sensor (SPLICS). However, inter-organelle distances (∼10-60 nm) for MERCs are lower than the 200-250 nm diffraction limited resolution obtained by standard confocal microscopy. Super-resolution microscopy of 3D volume analysis provides a two-fold resolution improvement (∼120 nm XY; 250 nm Z), which remains unable to resolve MERCs. MCS-DETECT, a membrane contact site (MCS) detection algorithm faithfully detects elongated ribosome-studded riboMERCs when applied to 3D STED super-resolution image volumes. Here, we expressed the SPLICS_L reporter in HeLa cells co-transfected with the ER reporter RFP-KDEL and label fixed cells with antibodies to RFP and the mitochondrial protein TOM20. MCS-DETECT analysis of 3D STED volumes was compared to contacts determined by co-occurrence colocalization analysis of mitochondria and ER or the SPLICS_L probe. Percent mitochondria coverage by MCS-DETECT derived contacts was significantly smaller than those obtained for colocalization analysis or SPLICS_L, and more closely matched contact site metrics obtained by 3D electron microscopy. Further, STED analysis localized a subset of the SPLICS_L label to mitochondria with some SPLICS_L puncta observed to be completely enveloped by mitochondria in 3D views. These data suggest that MCS-DETECT reports on a limited set of MERCs that more closely corresponds to those observed by EM.

Background: The integration of diverse clinical data sources requires standardization through models like OMOP (Observational Medical Outcomes Partnership). However, mapping data elements to OMOP concepts demands significant technical expertise and time. While large healthcare systems often have resources for OMOP conversion, smaller clinical trials and studies frequently lack such support, leaving valuable research data siloed.

Objective: To develop and validate a user-friendly tool that leverages large language models to automate the OMOP conversion process for clinical trial, electronic health record, and registry data.

Methods: We developed a three-tiered semantic matching system using GPT-3 embeddings to transform heterogeneous clinical data to the OMOP common data model. The system processes input terms by generating vector embeddings, computing cosine similarity against precomputed OHDSI vocabulary embeddings, and ranking potential matches. We validated the system using two independent datasets: a development set of 76 NIH HEAL Initiative clinical trial common data elements (CDEs) for chronic pain and opioid use disorders, and a separate validation set of electronic health record concepts from the NIH N3C COVID-19 enclave. The architecture combines UMLS semantic frameworks with asynchronous processing for efficient concept mapping, made available through an open-source implementation.

Results: The system achieved an Area Under the Receiver Operating Characteristic Curve (AUC) of 0.9975 for mapping clinical trial CDE terms. Precision ranged from 0.92 to 0.99 and recall from 0.88 to 0.97 across similarity thresholds from 0.85 to 1.0. In practical application, the tool successfully automated mappings that previously required manual informatics expertise, reducing the technical barriers for research teams to participate in large-scale data sharing initiatives. Representative mappings demonstrated high accuracy, such as demographic terms achieving 100% similarity with corresponding LOINC concepts. The implementation successfully processes diverse data types through both individual term mapping and batch processing capabilities.

Conclusions: Our validated LLM-based tool effectively automates the transformation of clinical data into OMOP format while maintaining high accuracy. The combination of semantic matching capabilities and researcher-friendly interface makes data harmonization accessible to smaller research teams without requiring extensive informatics support. This has direct implications for accelerating clinical research data standardization and enabling broader participation in initiatives like the NIH HEAL Data Ecosystem.

Cryptococcus neoformans, an invasive basidiomycete fungal pathogen, causes one of the most prevalent, life-threatening diseases in immunocompromised individuals and accounts for ~19% of AIDS-associated deaths. Therefore, understanding the pathogenesis of C. neoformans and its interactions with the host immune system is critical for developing therapeutics against cryptococcosis. Previous studies demonstrated that C. neoformans cells lacking polyphosphate (polyP), an immunomodulatory polyanionic storage molecule, display altered cell surface architecture but unimpaired virulence in a murine model of cryptococcosis. However, the relevance of cell surface changes and the role of hyperaccumulation of polyP in the virulence of C. neoformans remain unclear. Here we show that mutants with abundant polyP due to loss of the polyphosphatases Xpp1 and Epp1 are attenuated for virulence. The double mutant differed from the wild type during disease by demonstrating a higher fungal burden in disseminated organs at the experimental endpoint and by provoking an altered immune response. An analysis of triple mutants lacking the polyphosphatases and the Vtc4 protein for polyP synthesis also caused attenuated virulence in mice, thus suggesting an influence of Xpp1 and/or Epp1 independent of polyP levels. A more detailed characterization revealed that Xpp1 and Epp1 play multiple roles by contributing to the organization of the cell surface, virulence factor production, the response to stress, and mitochondrial function. Overall, we conclude that polyphosphatases have additional functions in the pathobiology of C. neoformans beyond an influence on polyP levels.IMPORTANCECryptococcus neoformans causes one of the most prevalent fungal diseases in people with compromised immune systems and accounts for ~19% of AIDS-associated deaths worldwide. The continual increase in the incidence of fungal infections and limited treatment options necessitate the development of new antifungal drugs and improved diagnostics. Polyphosphate (polyP), an under-explored biopolymer, functions as a storage molecule, modulates the host immune response, and contributes to the ability of some fungal and bacterial pathogens to cause disease. However, the role of polyP in cryptococcal disease remains unclear. In this study, we report that the polyphosphatase enzymes that regulate polyP synthesis and turnover contribute to the virulence of C. neoformans in a mouse model of cryptococcosis. The polyphosphatases influenced the survival of C. neoformans in macrophages and altered the host immune response. In addition, the mutants lacking the enzymes have changes in cell surface architecture and size, as well as defects in both mitochondrial function and the stress response. By using mutants defective in the polyphosphatases and polyP synthesis, we demonstrate that many of the phenotypic contributions of the polyphosphatases are independent of polyP.

Objective: This study aims to explore physical therapists' perspectives on providing physical therapy to First Nations peoples in Canada via telehealth, specifically to understand (1) their perspectives on the feasibility of telehealth as a medium for health care delivery and (2) their experiences building trusting therapeutic relationships via telehealth care.

Methods: This study included 13 physical therapists who provided clinical care via telehealth for First Nations individuals in northern British Columbia in the past 3 years, and 7 master of physical therapy students undergoing or who completed their Indigenous Health clinical placement in the past 3 years and utilized telehealth. In-depth semi-structured interviews were conducted. Interview questions explored: telehealth usage and acceptance, experiences with telehealth, and overall recommendations for telehealth. Audio recordings were transcribed, and reflexive thematic analysis was conducted.

Results: Three overarching themes were identified: "Telehealth can make a huge difference, but it is widely underutilized;" "Telehealth is a little bit less personal and in-depth;" and "There is a time and place for telehealth."

Conclusion: Telehealth shows promise in the delivery of physical therapy to First Nations communities in Canada, enhancing accessibility, offering flexible scheduling options, and optimizing therapist time efficiency. However, successful implementation in these communities is contingent upon addressing several challenges, including building trusting therapeutic relationships. Technological glitches, the absence of physical interaction, and a history of trauma may hinder the development of the therapeutic relationship in telehealth encounters. To mitigate these challenges, cultural safety training, initial in-person appointments, community familiarity, and in-person support from a caregiver or other health care provider may play pivotal roles.

Impact: This study not only sheds light on the underutilization of telehealth but also underscores its potential to significantly improve the accessibility and efficiency of physical therapy to First Nations peoples in Canada. The findings emphasize the nuanced dynamics of therapeutic relationships in telehealth, offering critical insights for the integration of culturally sensitive practices. Addressing the challenges pinpointed can enhance the quality of telehealth care for First Nations individuals, promote more equitable health care delivery, and foster positive health outcomes.

Background: The underrepresentation of students and professionals with disabilities in health professions is well-documented in research, emphasizing the urgent need for greater inclusivity. Institutional structures often restrict disabled individuals from sharing their specialized knowledge on navigating disability, perpetuating epistemic injustice. Research emphasizes the importance of amplifying their voices to address inequities and restore epistemic justice.

Objectives: This study explores the firsthand, experiential views of the challenges and supporting factors that disabled students and professionals face in the health professions education and practice. Participants provided advice for their disabled peers and non-disabled allies. The development of a critical disability epistemology amplifies underrepresented voices in the health field.

Design: This qualitative study was guided by a constructivist approach, with data analysis informed by reflective thematic analysis.

Methods: A series of semi-structured interviews were conducted with 56 participants (27 students and 29 professionals) in nursing, medicine, occupational therapy, physiotherapy, and social work. Participants were interviewed up to three times over the course of a year, resulting in a total of 124 interviews.

Results: Two main categories were identified. Category one, advice for disabled students and professionals, includes the themes: (1) Negotiating disclosure processes to mobilize support, (2) Recognizing personal boundaries and strengths while actively seeking mentorship, and (3) Advocating for oneself and others. Category two, advice for non-disabled allies, encompasses the themes: (4) Fostering inclusivity through thoughtful language, education, and support, and (5) Actively promoting systemic change.

Conclusion: The findings enhance the epistemic agency of disabled individuals by utilizing community resources for collective knowledge production. They offer valuable guidance for educators, institutions, and policymakers, providing a roadmap for making health education programs and workplaces more inclusive and supportive for disabled individuals.

Background: Inherited retinal diseases (IRDs) are genetic conditions that typically cause vision loss in working-age adults, representing a unique hidden disability characterised by variable progression rates.

Objective: This qualitative study explored the lived experiences of adults in the early stages of IRDs, when vision loss is not outwardly apparent.

Methods: Semi-structured interviews were conducted with 15 individuals with IRDs (mean age 37 ± 17 years) with experiences of progressive vision loss in the last 10 years, exploring participants' experiences and challenges following their IRD diagnosis. Interviews were transcribed verbatim and analysed using thematic analysis method.

Results: Analysis yielded five overarching themes: 1) Adapting to the diagnosis: "The journey can be harder than the actual disease", describing challenges in coming to terms with the diagnosis. 2) Daily obstacles: "Accepting what I have, adapting where I can", describing lifestyle and behavioural changes to accommodate for changing vision. 3) A roller-coaster of emotions: "I feel like I'm not in control of the journey", highlighting emotional challenges managing the uncertainty of a variable, progressive disease. 4) Navigating society: "it's invisible, so people forget", capturing interpersonal challenges stemming from a hidden disability. 5) The road ahead: Finding an identity within uncertainty, describing struggles with identity and the future.

Conclusion: Beyond vision impairment, individuals with IRDs face numerous personal and interpersonal challenges due to the hidden nature of their disability. These challenges are not always immediately apparent, highlighting the importance of raising awareness to assist in developing targeted resources, diagnostic support, and broader societal understanding for hidden disabilities.

Accurate diagnosis of both age-related macular degeneration (AMD) and inherited retinal diseases (IRD) with macular atrophy is important because treatments for both conditions are emerging. Phenotypical similarities between macular atrophy associated with AMD (geographic atrophy, GA) and IRD-associated atrophy exist, which can make accurate diagnosis challenging in clinical practice. Misdiagnosis may lead to inappropriate treatment strategies and missed opportunities for disease-specific interventions. A retrospective clinical review of medical records of people diagnosed with AMD between 1995 and 2023 from a large multidisciplinary private ophthalmic practice in Australia was undertaken to identify cases of patients diagnosed with geographic atrophy without drusen, which was then further assessed for potentially missed IRD with macular atrophy. Flagged cases were presented to experts in AMD and IRD to establish a most-likely diagnosis. Cases without consensus between graders were grouped into most-likely diagnosis by a third senior retinal clinician. Of the 1136 cases reviewed, the possible rate of misdiagnosis observed was 1.9%, with 1.0% representing potentially missed IRDs, most commonly pattern dystrophy (0.5%). A multi-modal approach, including clinical features and patient history, is important to limit the possibility of misdiagnosis of GA, and identify a subset of patients who might benefit from genetic testing prior to considering possible treatments.

The sarcin-ricin loop (SRL) is one of the most conserved segments of ribosomal RNA (rRNA). Translational GTPases (trGTPases), such as EF-G, EF-Tu, and IF2, form contacts with the SRL that are critical for GTP hydrolysis and factor function. Previous studies showed that expression of 23S rRNA lacking the SRL confers a dominant lethal phenotype in Escherichia coli Isolated ΔSRL particles were found to be not only inactive in protein synthesis but also incompletely assembled. In particular, block 4 of the subunit, which includes the peptidyl transferase center, remained unfolded. Here, we explore the basis of this assembly defect. We find that 23S rRNA extracted from ΔSRL subunits can be efficiently reconstituted into 50S subunits, and these reconstituted ΔSRL particles exhibit full peptidyl transferase activity. We also further characterize ΔSRL particles purified from cells, using cryo-EM and proteomic methods. These particles lack density for rRNA and r-proteins of block 4, consistent with earlier chemical probing data. Incubation of these particles with excess total r-protein of the large subunit (TP50) fails to restore substantial peptidyl transferase activity. Interestingly, proteomic analysis of control and mutant particles shows an overrepresentation of multiple assembly factors in the ΔSRL case. We propose that one or more GTPases normally act to release assembly factors, and this activity is blocked in the absence of the SRL.

Honey bee (Apis mellifera) colonies depend on the reproductive output of their queens, which in turn is contingent on the care they receive from worker bees. Viral infections in queens can compromise their reproductive output, while viral infections in workers can inhibit the successful functioning of the colony and its ability to care for the queen. Transgenerational immune priming (TGIP) occurs when queens transfer immune-related compounds or immune elicitors to their offspring, enhancing the ability of subsequent generations to resist infections. These maternal effects on offspring could positively impact colony health and resilience to viral infections, but little is currently known about TGIP for viruses in honey bees. In this study, we investigate how viral infections affect the proteomic composition of eggs laid by queens injected with a mixture of black queen cell virus and deformed wing virus B, both in controlled experimental settings and natural field conditions. Our results showed that virus-challenged queens upregulated immune effectors in their eggs and ovaries. In contrast, naturally infected queens from field surveys did not; there were no significant differences in egg protein, lipid, or metabolite composition related to maternal viral load or ovary size. However, egg collection date strongly influenced the protein, lipid, and metabolite composition of eggs, potentially reflecting seasonal variations in pollen resources. These findings suggest that while viral infections can induce transgenerational effects on egg proteomes under short-term experimental conditions, such effects are less apparent in natural settings and can be overshadowed by seasonal and other ecological factors.

No abstract available.

Background and objectives: Type 2 diabetes mellitus (T2DM) affects brain white matter microstructure. While diffusion tensor imaging (DTI) has been used to study white matter abnormalities in T2DM, it lacks specificity for complex white matter tracts. Neurite orientation dispersion and density imaging (NODDI) offers a more specific approach to characterising white matter microstructures. This study aims to explore white matter alterations in T2DM using both DTI and NODDI and assess their association with disease duration and glycaemic control, as indicated by HbA1c levels. Methods and Materials: We analysed white matter microstructure in 48 tracts using data from the UK Biobank, involving 1023 T2DM participants (39% women, mean age 66) and 30,744 non-T2DM controls (53% women, mean age 64). Participants underwent 3.0T multiparametric brain imaging, including T1-weighted and diffusion imaging for DTI and NODDI. We performed region-of-interest analyses on fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), radial diffusivity (RD), orientation dispersion index (ODI), intracellular volume fraction (ICVF), and isotropic water fraction (IsoVF) to assess white matter abnormalities. Results: We observed reduced FA and ICVF, and increased MD, AD, RD, ODI, and IsoVF in T2DM participants compared to controls (p < 0.05). These changes were associated with longer disease duration and higher HbA1c levels (0 < r ≤ 0.2, p < 0.05). NODDI identified microstructural changes in white matter that were proxies for reduced neurite density and disrupted fibre orientation, correlating with disease progression and poor glucose control. In conclusion, NODDI contributed to DTI in capturing white matter differences in participants with type 2 diabetes, suggesting the feasibility of NODDI in detecting white matter alterations in type 2 diabetes. Type 2 diabetes can cause white matter microstructural abnormalities that have associations with glucose control. Conclusions: The NODDI diffusion model allows the characterisation of white matter neuroaxonal pathology in type 2 diabetes, giving biophysical information for understanding the impact of type 2 diabetes on brain microstructure. Future research should focus on the longitudinal tracking of these microstructural changes to better understand their potential as early biomarkers for cognitive decline in T2DM.