Science Translational Medicine

Chikungunya virus (CHIKV) infection is typically not life-threatening but may, in rare cases, affect the central nervous system (CNS). In three cohorts of confirmed CHIKV cases from Martinique (French overseas territory) and Brazil (patients aged 0--89 years, n = 245), 20 patients had CNS infection (aged 17--87 years). Autoantibodies neutralizing type I interferons (AAN-I-IFN) were found in 35% of patients (4 male and 3 female, aged 17--87 years) with encephalitis (4/15), encephalomyelitis (1/2), or myelitis (2/3), but were absent in 225 patients without CNS infection. They neutralized high concentrations (10--1,000 ng/mL) of IFN-2, IFN-8, and IFN-{omega}, and the antibodies of one patient also neutralized IFN-{beta}. All samples also neutralized the other 10 IFN- subtypes (at least 100 pg/mL). This combination of blood autoantibodies occurs in ~0.02% and 0.6% of healthy individuals under and over 70 years of age, respectively. The presence of AAN-I-IFN before CHIKV infection therefore increased the risk of CNS disease ~850-fold relative to the general population.

Individuals with fibrodysplasia ossificans progressiva (FOP), a rare genetic disorder caused by mutations in the bone morphogenetic protein receptor ACVR1 (also known as ALK2), experience progressive and severely debilitating endochondral heterotopic ossification (HO). Previous studies have identified fibro-adipogenic progenitors (FAPs) as a major cellular source of HO in FOP mouse models. Here, we used mRNA sequencing of FAPs isolated from injured muscle of FOP mice to capture the earliest gene expression changes associated with the transformation of muscle tissues into bone. Whereas the transcriptomes of mutant and wild-type FAPs were indistinguishable prior to injury and at 1 day post injury, dramatic dysregulation of gene expression was observed at 3 and 5 days after injury. Surprisingly, gene expression changes suggested early specification of osteochondral lineages by 3 days post injury, approximately 3 to 4 days before the appearance of histologically identifiable cartilage. We identified dysregulation of genes encoding components of major signaling pathways, cell cycle regulators, extracellular matrix components, and hypoxia response mediators, and showed that these gene expression changes are temporally associated with abnormal population growth of mutant FAPs. We further demonstrated that treatment of FOP mice with either an anti-activin A monoclonal antibody or the ACVR1 kinase inhibitor BLU-782 (IPN60130; fidrisertib) normalized the expression of the majority of dysregulated FAP genes. However, the relative efficacy of the drugs differed, and distinct sets of overlapping genes were normalized by the treatments. The substantial transcriptional changes caused by these drugs in FAPs from normally regenerating muscle were also enumerated and described. These findings define early transcriptional events associated with pathogenic FAP reprogramming and provide a molecular framework for understanding the shared and distinct effects of activin A and ACVR1 inhibition.

Purpose: Neurofibromatosis type 2-related schwannomatosis (NF2-SWN) is an autosomal dominant tumor syndrome with complete penetrance and variable expressivity. Underlying patterns of disease burden and severity are largely unexplained. Methods: We comprehensively phenotyped 168 NF2-SWN patients over a mean duration of 4.5 years. We used a custom sequencing panel of NF2 and schwannomatosis genes to identify germline (n=166) and somatic variants in tumors (n=37). An optimized composite severity (CSS) score based on clinical and radiological data was created to analyze the effect of genetic variants on phenotype. Results: We found significant variable expressivity not explainable by demographic variables. Germline variants included premature termination (42%), splice-site (18%), and large deletions (16%). The CSS successfully predicted worsening clinical function in patients. Unsupervised clustering of clinical data revealed distinct phenotypic clusters that corresponded to CSS. Mosaicism, however, was not associated with CSS or any other disease severity marker. CSS was significantly associated with germline variant location along the NF2 locus. Specifically, FERM-F1 and the -helical variants were associated with increased disease severity. Within tumors, germline variants with severe effects on merlin acquired milder somatic second-hits at the NF2 locus. Conclusion: We identified a second-hit modifier to the Mendelian first-hit: severe germline variants were associated with milder somatic variants, and vice versa. This phenomenon partly explains the variable expressivity in NF2-SWN.

Scalable human models that capture interactions between distinct tissues remain limited, constraining mechanistic insight and therapeutic prediction. Here, we established a scalable, automation-compatible human neuromuscular organoid (NMO) platform that enables integrated analysis of neuronal and muscle lineages in spinal muscular atrophy (SMA). Patient-derived NMOs reproducibly self-organise into spinal cord and skeletal muscle compartments and form functional neuromuscular circuits. SMA NMOs recapitulate early disease features, including reduced survival motor neuron (SMN) protein levels and impaired neuromuscular junction (NMJ) maturation. Single-nucleus RNA sequencing identifies lineage-specific transcriptional changes across neuronal and muscle compartments preceding functional deficits. Using this platform, we compared two clinically relevant SMN2 splicing modulators and observed distinct, cell-type-dependent responses. While both compounds increased SMN levels and NMJ number, only one enhanced myofiber growth and improved contractile function. These findings highlight muscle maturation, rather than NMJ number alone, as a key determinant of functional recovery and establish NMOs as a scalable system for studying cell-type-specific therapeutic responses.

Defining how human host factors shape HIV-1 infection in vivo remains essential for the development of genetically engineered cell therapies. Here, we established a non-viral CRISPR/Cas9 ribonucleoprotein-based platform for efficient single and multiplex gene editing in primary human CD34+ hematopoietic stem and progenitor cells (HSPCs). Edited HSPCs retained viability, proliferative capacity, primitive immunophenotypes, and multilineage differentiation potential and supported targeted reporter knock-in independently of the cell source, cord blood (CB), bone marrow (BM), and mobilized from peripheral blood (MPB). Following differentiation, SAMHD1 knockout increased HIV-1 susceptibility of HSPC-derived macrophages, MX2 knockout also increased HIV infection in cells pre-stimulated with IFN-2a, and CXCR4 knockout blocked X4-tropic HIV-1 infection of HSPC-derived megakaryocytes. We then transplanted CCR5-, SAMHD1-, or non-targeting control-edited HSPCs into immunodeficient mice and challenged reconstituted animals with R5-tropic HIV-1. CCR5 knockout prevented detectable viral spread, validating the model using a clinically relevant dependency factor. In contrast, SAMHD1 knockout accelerated viral dissemination, with earlier plasma viremia and 3.6-fold higher cumulative viremia, although endpoint viral burden was not significantly different from controls. These findings establish transplantation of CRISPR/Cas9-edited human HSPCs as a modular platform for dissecting HIV-1 host-factor function across hematopoietic lineages ex vivo and in vivo and for evaluating engineered cell-based strategies.

Duchenne muscular dystrophy (DMD) is classically defined as a primary myopathy, and current AAV-mediated microdystrophin gene therapies are shown to successfully preserve muscle integrity. However, their efficacy in recovering functional outcomes remains to improve. We hypothesized that this limitation stems from an unaccounted vulnerability within the peripheral nerve. Here, we demonstrate that the mdx mouse model exhibits a peripheral axonopathy independently of muscle necrosis. Using single-nucleus RNA sequencing and structural analyses, we have identified an active denervation program and a profound failure of neural repair pathways. Importantly, we revealed that the full-length dystrophin isoform Dp427c is expressed in the healthy peripheral nerve, intimately following the cytoskeletal organization and accumulating at regions of high biomechanical stress, including Schmidt-Lanterman incisures and Nodes of Ranvier. In its absence, nerves of mdx mice loss an essential scaffolding support, leading to localized structural collapse. Furthermore, we showed that muscle-restricted microdystrophin gene therapy rescues sarcolemmal integrity but failed to restore nerve-muscle connectivity or resolved neurotransmission defects. These findings fundamentally redefine DMD as an integrated motor unit pathology, thereby underscoring the absolute necessity of implementing combined therapeutic strategies that target both the muscle and the peripheral nervous system.

Fibrotic skin diseases are characterized by persistent fibroblast activation and extracellular matrix remodeling, yet the mechanisms governing fibroblast state transitions remain incompletely understood. Here, we established a human iPSC-derived skin organoid model of fibrosis through chronic TGF-{beta} stimulation. Single-cell RNA sequencing combined with immunofluorescence-based spatial analysis revealed dynamic fibroblast state transitions, spatial reorganization, and expansion of activated fibroblast populations during fibrotic remodeling. Integration with human scleroderma single-cell datasets demonstrated conserved fibroblast states and transcriptional programs between organoids and patient tissues. We further identified broad induction of RUNX2 in the dermal compartment during fibrosis, and RUNX2 depletion attenuated fibrotic marker expression. CUT&RUN profiling revealed RUNX2 occupancy at fibrosis-associated loci, including RUNX1 and LOXL2. Using a machine learning-guided screening approach, we identified F0565-0303, a small molecule that suppressed RUNX2-dependent fibrotic programs in vitro and reduced fibrosis in a bleomycin-induced mouse model. Together, these findings establish human skin organoids as a platform for modeling fibrosis and nominate RUNX2 as a potential therapeutic target.

CD28 costimulation contributes to pathogenic T cell responses in inflammatory bowel disease (IBD), but current B7-directed blockade also limits CTLA-4 signaling. Using a sensitive NanoBiT split-luciferase screening platform, we identified and optimized CA-23, a small molecule antagonist that directly binds human and mouse CD28 without measurable binding to CD80, CD86, or CTLA-4. CA-23 inhibited CD28-B7 engagement and CD28-dependent T cell activation without agonist activity in human whole blood and peripheral blood mononuclear cells. CA-23 achieved exposure in the colon and mesenteric lymph nodes and reduced disease severity, histologic injury, and pathogenic Th1 and Th17 responses in a T cell transfer model of colitis. In PBMCs from donors with ulcerative colitis or Crohns disease, CA-23 suppressed inflammatory cytokine production and T cell activation to a degree matching or exceeding Abatacept. In human intestinal epithelial-PBMC co-cultures, CA-23 preserved Treg suppressive activity and epithelial barrier integrity, whereas Abatacept reduced Treg function. CA-23 did not alter CD80 or CD86 expression on autologous antigen-presenting cells and showed no substantial off-target activity in the tested selectivity panel. These findings support direct CD28 antagonism as a mechanistically differentiated alternative to B7-directed co-stimulation blockade for suppressing pathogenic T cell responses in preclinical models of IBD. One Sentence SummaryA CD28-selective small molecule blocks pathogenic T cell activation and preserves Treg function unlike Abatacept in IBD models.

Background: SARS-CoV-2 vaccines have been updated based on circulating variants and the antibody protection from prior vaccination and infection against emerging variants. We evaluated longitudinal antibody correlates of SARS-CoV-2 infection risk during Omicron waves. Methods: We used data from a longitudinal cohort study from 2021 through 2025 with prospective surveillance for acute respiratory illness and repeated blood collection. A subset of participants also provided weekly respiratory specimens to identify asymptomatic infections. Serum samples were tested using multiplex assays measuring anti-Spike (S) binding IgG and angiotensin-converting enzyme 2 (ACE2) inhibition, a measure of inhibition of the ACE2 receptor interaction, across multiple SARS-CoV-2 variants. Cox models were used to evaluate associations between antibody levels, prior vaccination and infection, and SARS-CoV-2 infections. Findings: Among 119 participants who contributed 438.8 person-years of follow-up, 81 symptomatic SARS-CoV-2 infections and 4 asymptomatic infections (from 33 participants with weekly swabs) were detected. Each two-fold increase in anti-S IgG concentration was associated with a 15% lower hazard of symptomatic infection (hazard ratio [HR] = 0.85, 95% CI: 0.82-0.88). Similarly, each 10% increase in ACE2 inhibition was associated with a 7% lower infection hazard (HR = 0.93, 95% CI: 0.90-0.95). After adjusting for antibody levels, prior SARS-CoV-2 infection remained protective, while recent vaccination was not associated with infection hazard. The peak predicted antibody level after repeated COVID-19 vaccinations was estimated to confer 62-65% protection against symptomatic infection. Interpretation: Higher levels of binding and functional antibodies were associated with reduced risk of SARS-CoV-2 infections across multiple waves between 2021-2025. These findings support the use of longitudinal serologic surveillance to inform vaccine evaluation and future booster strategies against evolving SARS-CoV-2 variants.

Fibrosis severity is routinely inferred from collagen abundance, although whether collagen quantity determines pathological fibrosis remains unclear. In Duchenne muscular dystrophy (DMD), chronic muscle injury and inflammation drive extracellular matrix accumulation, making these processes difficult to disentangle. We exploit sarcospan overexpression in mdx mice, a model of DMD (mdxTG), which improves membrane integrity and muscle function despite persistent matrix remodeling. mdxTG muscle accumulates more collagen than mdx yet lacks its dense macrophage-rich scars. Matrisome proteomics and spatial transcriptomics reveal compositionally and spatially distinct matrix states, while decellularized mdxTG matrix protects myotubes from membrane damage relative to mdx matrix. Despite these differences, both dystrophic matrices remain stiff and induce nuclear YAP in fibro-adipogenic progenitors. Verteporfin suppresses collagen production and reduces fibrosis in vivo, while nuclear YAP is increased in FAPs from patients with DMD. Thus, collagen abundance alone does not define pathological fibrosis; matrix organization, biological activity, and mechanosignaling distinguish functionally distinct fibrotic states.

Mitochondrial DNA depletion syndromes (MDS) are inherited conditions caused by pathogenic variants in mitochondrial DNA maintenance genes. Most MDS are severe, fatal and incurable conditions. Mitochondrial neurogastrointestinal encephalomyopathy (MNGIE) is an MDS resulting from loss-of-function mutations in the TYMP gene, encoding Thymidine Phosphorylase (TP). Systemic nucleoside accumulation caused by TP deficiency disrupts mitochondrial nucleotide homeostasis, which underlies disease progression and mortality. Current treatments, including liver and hematopoietic stem cell transplantation, partially restore TP activity but are invasive, carry substantial risk and are limited by donor availability. Here, we establish TYMP-mRNA in lipid nanoparticles (hTYMP-mRNA-LNPs) as a safe non-viral protein-replacement therapy for MNGIE. Intravenous administration of hTYMP-mRNA-LNPs induced robust hepatic TP expression in a mouse model of MNGIE, was well tolerated and restored circulating nucleosides to wild-type levels within hours, lasting up to three weeks, at a preclinical minimally effective dose of 0.25mg/kg. To facilitate repeat administration and patient access, we demonstrate enhanced efficiency of subcutaneous mRNA-LNP delivery by co-administration of recombinant or mRNA-encoded (SPAM1-mRNA-LNPs) hyaluronidase, achieving effective hepatic TP expression and systemic nucleoside clearance. These findings establish mRNA-LNP-mediated protein replacement as a therapeutic strategy for a primary mitochondrial disease where transient liver-targeted expression is sufficient to correct a systemic metabolic defect. More broadly, our results support the development of mRNA-LNP therapeutics and their subcutaneous delivery as a generalizable platform for treating monogenic diseases, through repeatable, non-viral protein replacement.

BACKGROUND: Increased left ventricular mass (LVM) at a single time point after heart transplantation (HT) predicts future adverse outcomes. However, dynamic changes in LVM could have better biological relevance and reflect adverse graft remodeling (AGR). The prognostic significance of such serial changes has not been studied. METHODS: Using an automated, electronic health record-based institutional data infrastructure, we studied 439 HT recipients with 5,563 LVM measurements. Separate Bayesian joint models estimated the simultaneous associations of current LVM and its instantaneous rate of change with graft dysfunction (GD) and mortality. A joint-model-derived remodeling score combining patient-specific deviations in LVM and slope was dichotomized to define AGR and non-AGR groups. A mixed-effects analysis of all clinical variables was performed to assess associations with LVM both between and within patients. An independent cohort of 35 patients with 79 surveillance-biopsy RNA-sequencing samples was used to examine early stress-responsive pathways associated with the remodeling score. RESULTS: LVM declined by approximately 7 g/year after transplantation, with regression attenuating over time. Sixty patients (13.7%) had GD, and 75 (17.1%) died. Higher LVM was associated with subsequent GD (hazard ratio [HR] per 10 g, 1.14; 95% credible interval [CrI], 1.02-1.28) and mortality (HR, 1.10; 95% CrI, 1.02-1.19). A more positive LVM slope was associated with GD (HR per 1 g/year, 1.21; 95% CrI, 1.06-1.42) and with cardiac allograft vasculopathy (CAV) grade 2 or 3 (HR, 1.39; 95% Crl, 1.02-1.96). LVM regressed more slowly in the AGR group (-5.8 vs -8.4 g/year), with higher GD (21.0% vs 6.4%) and mortality (24.2% vs 10.0%). Time-updated GD was associated with subsequent death (HR, 8.12; 95% Confidence Interval [CI], 4.67-14.14). Transcriptomic analysis showed enrichment of interferon-mediated signaling and vascular endothelial activation with higher remodeling scores, whereas lower scores were associated with mitochondrial and metabolic processes, ribosome biogenesis, and pathways related to tissue repair and stress responses. CONCLUSIONS: AGR is an easily accessible imaging biomarker that reflects the changes in the allograft in response to various stressors and predicts future adverse outcomes. Discovery of molecular mechanisms of AGR could lead to novel therapies to protect the allograft from chronic rejection.

Chronic IL-1{beta}-driven inflammation contributes to cardiovascular risk and potentially HIV reservoir persistence in people with HIV (PWH) but the effects of direct IL-1{beta} blockade have not been defined. We show that canakinumab, an anti-IL-1{beta} monoclonal antibody, induces a unique set of genes (Cana_Up) and suppresses a unique set of genes (Cana_Down) in whole blood sequencing that are both associated with reduced HIV reservoir. We validated the association of Cana_Up genes with low reservoir in an independent dataset. Cana_Up genes are expressed mainly by CD4 and CD8 T cells and map to pathways of cell cycling (Myc, E2F, G2M) and antigen presentation. Th17 cells in the blood and tissue resident HIV reservoir in the gut express pathways targeted by canakinumab to reduce reservoir. Participants with reduced reservoir after canakinumab show enhanced HIV-specific CD4 and CD8 effector function. Cana_Down genes are expressed the highest by CD14+ monocytes, which are a confirmed source of IL-1b in our study, and map to inflammatory pathways (NF-kB, RELA) and PRC1/2 complex members that regulate epigenetics (EZH2, JARID2). These findings establish a mechanistic rationale for IL-1{beta} blockade as an immune reconditioning strategy in HIV that can reverse monocyte driven inflammatory dysfunction and enhance HIV-specific CD4 and CD8 effector responses to effectively target the HIV reservoir.

Among the many subtypes of Charcot-Marie-Tooth (CMT) disease, several result from mutations in genes encoding aminoacyl-tRNA synthetases, enzymes required for tRNA charging during cytoplasmic and mitochondrial translation. We report that activation of the integrated stress response (ISR) pathway is a shared molecular feature of tRNA synthetase-associated and other axonal CMT subtypes. RTX-117, a CNS-penetrant small molecule currently in Phase 1 clinical trials, targets eukaryotic initiation factor 2B (eIF2B), a key modulator of protein synthesis and the ISR pathway. Using cryo-EM studies, we have characterized the binding mode of RTX-117 to the eIF2B decamer. In GarsP278KY/+ mice, which develop early onset motor defects and axonal pathology that recapitulate CMT2D symptoms from tRNA synthetase mutations, RTX-117 treatment started after disease onset reduced chronic ISR activation and produced significant functional and electrophysiological improvement. We further identify ISR targets, including secreted proteins such as GDF15 and FGF21 that may serve as translational biomarkers for treatment response to RTX-117 in CMT disease. Broader surveillance of the ISR pathway across models of neurodegeneration reveals strong activation in several diseases and a correlation with disease progression, particularly in models of Alzheimers disease. These findings identify chronic ISR activation as a recurrent, though not universal, pathological mechanism of neurodegenerative disease models. Overall, our study identifies candidate biomarkers for CMT disease subtypes associated with defects in translational homeostasis and supports eIF2[a]-ATF4 axis modulation as a promising therapeutic strategy for this disease class. One Sentence SummaryRTX-117, a clinical stage eIF2B activator, blunts chronic ISR activation and improves nerve and motor function in a mouse model of Charcot-Marie-Tooth Disease Type 2D.

Cardiac fibrosis is causally linked to heart failure progression and survival. Currently, there are no approved treatments that directly target cardiac fibrosis. Recent studies have identified a subset of activated cardiac fibroblasts distinct from myofibroblasts that are marked by fibroblast activation protein (FAP) expression, emerge in the injured and diseased heart through inflammatory signaling, and contribute to fibrosis. Using a genetic mouse model, we demonstrate the potential benefits of FAP+ fibroblast depletion following myocardial infarction. Unexpectedly, while FAP targeted bispecific T-cell engaging antibodies (BiTE(R) molecules) effectively eliminate FAP+ fibroblasts from the heart, they surprisingly lead to accelerated deterioration of cardiac function, enhanced remodeling, and increased scar size. FAP BiTE(R) molecules elicit a robust cytokine response within the heart with prominent activation of interferon gamma (IFNg) and CD40 ligand pathways. Target cell killing was independent of IFNg; and CD40L signaling and blockade of these pathways was sufficient to unmask the protective therapeutic effects of FAP+ fibroblast depletion. Mechanistically, we reveal that IFNg; signaling to fibroblasts drives the differentiation of an independent lineage of activated fibroblasts not typically found in the infarcted heart, which are responsible for the harmful effects of FAP BiTE(R) molecules. Collectively, these findings highlight a previously unrecognized cardiac liability of BiTE(R) molecules and inform the design of the next generation of therapeutics.

Inflammatory bowel disease (IBD) is a heterogeneous chronic disease driven by dysregulated mucosal immunity and impaired epithelial barrier function. Although biologics have improved disease management, they are frequently associated with systemic immunosuppression and adverse effects, highlighting the need for localized therapeutic strategies that both control inflammation and promote tissue repair. Here, we developed a protein bispecific termed 7A2-IgG4-IL22, composed of a human IgG4-Fc domain displaying an antagonistic anti-human MAdCAM-1 single chain (sc)-Fv and a human interleukin (IL-)22. The anti-MAdCAM-1 scFv retained the functional activity of the parental monoclonal antibody, inhibiting T cell activation, expansion and differentiation from naive precursors. Blockade of the MAdCAM-1 signaling axis also reduced production of pro-inflammatory cytokines relevant to IBD pathogenesis, including IFN{gamma} and TNF. On the epithelial side, the IL-22 cargo induces robust signaling in epithelial cells, promoting the expression of IL-22 response genes associated with antimicrobial defense, mucosal homeostasis, as well as IL-10 and CXCL1 expression. This effect contributes to immune cell trafficking to the intestinal mucosa. Together, this bispecific provides a localized dual-mechanism strategy for restoring intestinal immune homeostasis.

Focused ultrasound (FUS) is a promising noninvasive neuromodulation approach, but whether it can directly activate central auditory neurons in vivo remains unresolved. We applied high-frequency FUS (20 MHz) to the central nucleus of the inferior colliculus (CNIC) in anesthetized guinea pigs while recording electrophysiological responses from the auditory pathway and cochlea. FUS evoked cortical activity through indirect cochlear activation, possibly via skull-mediated mechanical coupling, rather than direct inferior colliculus activation, with ultrasound-evoked compound action potentials predominating in the ipsilateral cochlea. More interestingly, FUS stimulation of the CNIC induced activation of neurons and glial cells in the CNIC and auditory cortex as demonstrated by c-Fos expression, suggesting that FUS stimulation activated the afferent pathway. We also show that FUS engaged the auditory efferent system, likely via medial olivocochlear neurons, producing reduced compound action potential amplitudes, enhanced cochlear microphonics, and persistent effects lasting at least two hours, consistent with long-lasting efferent plasticity. Strikingly, FUS administered before acoustic trauma almost completely prevented noise-induced hearing loss, limiting auditory brainstem response threshold shifts to <10 dB versus ~60 dB in controls. Gentamicin abolished these physiological and protective effects, implicating medial olivocochlear activation. These findings identify FUS as a potent noninvasive strategy for engaging auditory efferent circuits and protecting against acoustic injury.

Beyond its critical roles in development and tissue homeostasis, TGF{beta} signaling promotes key aspects of cancer progression and is a primary driver of fibrosis. Although blocking TGF{beta} signaling has great therapeutic potential for cancer and fibrotic diseases such as idiopathic pulmonary fibrosis (IPF), preclinical and clinical studies revealed that non-specific alteration of the pathway can have severe adverse consequences; therefore, inhibiting TGF{beta} signaling in a cell-type specific manner may avoid systemic toxic effects while preserving potential therapeutic effects. The parasitic helminth Heligmosomoides polygyrus has evolved cell-type-targeted modulators of TGF{beta} signaling. With insights from the development of other targeted signaling modulators and using the worm proteins as a guide, we sought to develop a human-fibroblast-targeted TGFBR2 antagonist. Here, we report mechanistic insights into the targeted worm TGFBR2 antagonist TGM6 and fusion proteins containing the TGM6 targeting domains. We created a bispecific antibody TGFBR2 antagonist that binds PDGFRA as a targeting receptor and demonstrates cell selectivity and enhanced potency in fibroblasts. Our findings suggest a viable path for developing targeted TGF{beta} signaling antagonists as therapeutics for cancer and tissue fibrosis.

Beckwith-Wiedemann syndrome (BWS) is a pediatric imprinting disorder characterized by tissue overgrowth, most commonly macroglossia, which can result in airway and feeding complications. Although dysregulated growth is a defining feature of BWS, the cellular interactions that drive organ-specific overgrowth remain poorly understood. We previously demonstrated that BWS macroglossia arises through distinct cell-intrinsic and cell-extrinsic mechanisms depending on molecular subtype. Here, we identify fibroadipogenic progenitor cells (FAPs) as modulators of myogenic differentiation and fusion in the human BWS tongue. BWS-derived FAPs were not increased in abundance in situ and did not exhibit hyperproliferation in vitro. Instead, FAPs from one BWS subtype promoted enhanced differentiation and fusion of normal human myoblasts. Secretome profiling revealed enrichment of CATHEPSIN L and TRANSFERRIN in conditioned media from these FAP populations, and functional perturbation of these factors supported their role in regulating myogenesis. These findings define a non-cell-autonomous mechanism of muscle overgrowth and implicate mesenchymal-myogenic signaling as a context-dependent driver of tissue expansion in an imprinting disorder.

To characterize anti-nucleocapsid (anti-N) IgG binding antibody responses following first PCR-confirmed SARS-CoV-2 infections in a highly vaccinated population, we evaluated antibody boosting and durability in a longitudinal cohort in Michigan. Among 113 participants with paired pre- and post-infection serum specimens tested using a multiplex electrochemiluminescence assay, SARS-CoV-2 infection induced substantial boosting of anti-N IgG concentrations; approximately 80% of participants becoming anti-N seropositive following infection, and 81% of participants demonstrating at least a 4-fold rise in antibody concentrations following infection. Population-level analyses of 66 participants with post-infection serum specimens collected 52-120 days after infection demonstrated sustained anti-N IgG concentrations over time, with no evidence of substantial decline. These findings demonstrate robust boosting and sustained infection-induced anti-N IgG responses in a highly vaccinated population through four months following SARS-CoV-2 infection. This supports the use of anti-N antibodies for longitudinal serosurveillance, including those who are vaccinated.