Biology subjects

Sutton, V. R.

Publications and source records attributed to Sutton, V. R..

7 recordsLinked to original sources

bioRxiv2025

Pathogenic DVL frameshifting variants in Robinow syndrome disrupt WNT signaling and cellular dynamics

Robinow syndrome (RS) is a genetically heterogeneous rare disorder involving six genes in the WNT/planar cell polarity (PCP) signaling pathway. Frameshifting variants in DVL genes that introduce a novel basic C-terminus are a common cause of autosomal dominant RS, accounting for [~]33% of individuals without ROR2 variants. Here, we review ClinVar and literature variants affecting DVL paralogs resulting in RS and investigate the cellular effects of pathogenic DVL frameshift variants with mutant tails replacing at least 82 amino acids. In silico analysis of the new C-termini revealed altered intrinsically disordered regions (IDRs), charge distribution, and predicted protein structures. To explore potential altered biological mechanisms caused by novel C-termini, we generated wild-type (WT), frameshift, and truncated constructs of DVL1-3, and analyzed their behavior in a transfection-based in vitro systems. DVL proteins normally polymerize into cytoplasmic puncta that redistribute upon WNT stimulation. Immunocytochemistry showed that mutant DVL proteins failed to change their localization in response to WNT ligands, in contrast to WT alleles--a consistent observation across all three DVLs. In line with this, TOPFlash reporter assays demonstrated that mutant DVL1 and DVL3 failed to activate canonical WNT signaling, while WT proteins induced strong activation. Additionally, the mutant C-terminal tail interfered with CSNK1E-induced phosphorylation, offering a potential mechanism underlying the impaired WNT response. Our results provide further understanding of the cellular consequences of pathogenic DVL frameshifting variants and offers insights into the effects of such alleles on WNT signaling, and the perturbations thereof, that may lead to developmental phenotypes observed in RS.

genetics↗

bioRxiv2025

A TAK1Cytokine Toxicity Checkpoint Controls Anti-Cancer Immunity

The success of cancer immunotherapies is currently limited to a subset of patients, which underscores the urgent need to identify the processes by which tumours evade immunity. Through screening a kinome-wide CRISPR/Cas9 sgRNA library we identified MAP3K7 (TAK1) as a suppressor of CD8+ T cell mediated killing. We demonstrate that TAK1 acts as a cancer-intrinsic checkpoint by integrating signals from T cell-secreted TNF and IFNy effector cytokines to elicit a cytoprotective response. This cytoprotective response profoundly limits the anti-cancer activity these key effector molecules and completely abrogates bystander killing by perforin deficient T cells. Inhibition of the TAK1 checkpoint effectively redirects the combined TNF/IFNy pathway activation to promote inflammatory cell death via RIPK1 and Caspase-8 and simultaneously amplifies the output of the IFNy pathway, thereby priming cells for cytokine-induced cell death. Mechanistically, TAK1 deficiency led to proteasomal degradation of cFLIP, enhancing the formation of Complex II and subversion of other cytoprotective responses. Targeting the TAK1 checkpoint led to profound attenuation of tumour growth in immune competent mice, with minimal impact in immune deficient counterparts. Adoptive cell therapy led to preferential elimination of TAK1 deficient clones. Collectively, our study uncovers a cancer-intrinsic checkpoint controlled by TAK1 activity that switches TNF and IFNy responses from cytoprotective to apoptosis. Cancer cells exploit this to limit cell death in the presence of the cytotoxic lymphoctye cytokines TNF and IFN{gamma} and therapeutic intervention can fully unleash the impact of these effector molecules both on the direct target and bystander cells. These findings highlight the clinical development of TAK1 biologics as a potential strategy to improve cancer immunotherapies through harnessing and enhancing the cytotoxic potential of CTL-derived cytokines. In BriefDjajawi et al. identify TAK1 as a cancer-intrinsic cytokine toxicity checkpoint that limits the efficacy of anti-cancer immune responses. Cancer cells exploit TAK1 activity to confers resistance to CD8+ T cell-derived TNF and IFN{gamma}-induced apoptosis, limiting both direct and bystander killing. Mechanistically, TAK1 loss acts through 1. cFLIP and RIPK1 to promote cell death, 2. The inactivation of pro-survival signals and 3. Via amplification of the IFNy response. Targeting of this TAK1 checkpoint enhanced anti-tumour immunity in vivo and improved adoptive cellular therapy. These findings identify a strategy employed by transformed cells to avoid destruction by inflammatory cytokines and provide new therapeutic vulnerabilities for enhancing immunotherapies. HighlightsO_LICRISPR screens identify TAK1 as a tumour-intrinsic survival checkpoint limiting destruction by CD8+ T cells. C_LIO_LITAK1 protects tumour cells from combined TNF and IFN{gamma}-induced apoptosis. C_LIO_LITAK1 loss destabilizes cFLIP, priming cells for STAT1 and RIPK1-dependent cell death. C_LIO_LITAK1 loss promotes tumour control in immune competent animals and enhances the efficacy of adoptive cell therapy. C_LI

cancer biology↗

bioRxiv2024

The Multifunctional Catalytic Hemoglobin from Amphitrite ornata: Protocols on Isolation, Taxonomic Identification, Protein Extraction, Purification, and Characterization

The multifunctional catalytic hemoglobin from the terebellid polychaete Amphitrite ornata, also named dehaloperoxidase (AoDHP), utilizes the typical oxygen transport function in addition to four observed activities involved in substrate oxidation. The multifunctional ability of AoDHP is presently a rare observation, and there exists a limitation for how novel dehaloperoxidases can be identified from macrobenthic infauna. In order to discover more infaunal DHP-bearing candidates, we have devised a facilitated method for an accurate taxonomic identification that places visual and molecular taxonomic approaches in parallel. Traditional visual taxonomic species identification by the non-specialist, at least for A. ornata, or even for other marine worms, is a very difficult and time-consuming task since a large diversity is present and the method is restricted to adult worm specimens. The work herein aimed to describe a method that particularly simplifies the taxonomic identification of A. ornata through the assessment of its mitochondrial cytochrome c oxidase subunit I gene by employing the DNA barcoding technique. Furthermore, whole worm specimens of A. ornata were used to extract and purify AoDHP followed by an H2O2-dependent peroxidase activity assay evaluation against substrate 2,4,6-trichlorophenol. AoDHP isoenzyme A was also overexpressed as the recombinant protein in Escherichia coli, and its peroxidase activity parameters were compared to AoDHP from the natural source. The activity assay assessment indicated a tight correlation for all Michaelis-Menten parameters evaluated. We conclude that the method described herein exhibits a streamlined approach to identify the polychaete A. ornata, which can be adopted by the non-specialist, and the full procedure is predicted to facilitate the discovery of novel dehaloperoxidases from other marine invertebrates.

biochemistry↗

bioRxiv2020

COPB2 haploinsufficiency causes a coatopathy with osteoporosis and developmental delay

Coatomer complexes function in the sorting and trafficking of proteins between subcellular organelles. Pathogenic variants in coatomer subunits or associated factors have been reported in multi-systemic disorders, i.e., coatopathies, that can affect the skeletal and central nervous systems. We have identified loss-of-function variants in COPB2, a component of the coatomer complex I (COPI), in individuals presenting with osteoporosis, fractures and developmental delay of variable severity. Because the role of COPB2 in bone has not been characterized, we studied the effect of COPB2 deficiency on skeletal development in mice and zebrafish. Copb2+/- mice showed low bone mass and decreased bone strength. In zebrafish, larvae carrying a copb2 heterozygous frameshift variant showed delayed mineralization. copb2-null embryos showed endoplasmic reticulum (ER) and Golgi disorganization, and embryonic lethality. COPB2 siRNA-treated fibroblasts showed delayed collagen trafficking with retention of type I collagen in the ER and Golgi, and altered distribution of Golgi markers. Our data suggest that COPB2 haploinsufficiency leads to disruption of intracellular collagen trafficking and osteoporosis, which may improve with ascorbic acid supplementation. This work highlights the role of COPI complex as a critical regulator of bone mass and identifies a new form of coatopathy due to COPB2 deficiency.

genetics↗

bioRxiv2020

Cell-based analysis of CAD variants identifies individuals likely to benefit from uridine therapy

PurposePathogenic autosomal recessive variants in CAD, encoding the multienzymatic protein initiating pyrimidine de novo biosynthesis, cause a severe inborn metabolic disorder treatable with a dietary supplement of uridine. This condition is difficult to diagnose given the large size of CAD with over 1000 missense variants and the non-specific clinical presentation. We aimed to develop a reliable and discerning assay to assess the pathogenicity of CAD variants and to select affected individuals that might benefit from uridine therapy. MethodsUsing CRISPR/Cas9, we generated a human CAD-knockout cell line that requires uridine supplements for survival. Transient transfection of the knockout cells with recombinant CAD restores growth in absence of uridine. This system determines missense variants that inactivate CAD and do not rescue the growth phenotype. ResultsWe identified 25 individuals with biallelic variants in CAD and a phenotype consistent with a CAD deficit. We used the CAD-knockout complementation assay to test a total of 34 variants, identifying 16 as deleterious for CAD activity. Combination of these pathogenic variants confirmed 11 subjects with a CAD deficit, for whom we describe the clinical phenotype. ConclusionsWe designed a cell-based assay to test the pathogenicity of CAD variants, identifying 11 CAD deficient individuals, who could benefit from uridine therapy.

genetics↗

bioRxiv2018

Assessing Disease Experience across the Life Span for Individuals with Osteogenesis Imperfecta: Challenges and Opportunities for Patient-Reported Outcomes (PROs) Measurement

BackgroundPatient reported outcome (PRO) information is crucial for establishing better patient-provider communication, improving shared decision making between clinicians and patients, and assessing patient responses to therapeutic interventions and increasing satisfaction with care. We used the Brittle Bones Disease Consortium (BBDC) Contact Registry for People with OI, managed by the Rare Disease Clinical Research Network (RDCRN) to (1) to evaluate the construct validity of the Patient-Reported Outcome Measurement Information System(R) (PROMIS(R)) to record important components of the disease experience among individuals with OI; and (2) explore the feasibility of using a registry to recruit individuals with OI to report on health status. Our long-term goal is to enhance communication of health and disease management findings back to the OI community, especially those who do not have access to major OI clinical centers.\n\nResultsWe demonstrated the construct validity of PROMIS instruments in OI. Our results confirm that the scores from most domains differ significantly from the general US population: individuals with OI have worse symptom burden and functioning. We found no excessive floor or ceiling effects. Our study demonstrates that the BBDC Contact Registry can be used to recruit participants for online health status surveys. However, there are numerous challenges that must be addressed: lack of self-knowledge of OI type, under-representation of men, limited ethnic diversity, and imperfect questionnaire completion rates.\n\nConclusionOur pilot study demonstrated the feasibility of using a contact registry to recruit respondents from the OI community and to obtain analyzable PROMIS data regarding disease experience. Because the results differ from the general population and avoid excessive floor and ceiling effects, PROMIS instruments can be used to assess response to therapeutic interventions in individuals with OI. Future directions will include (1) development and validation of an OI-specific patient-based classification system that aggregates persons with similar clinical characteristics and risks for complications to identify treatment needs; and (2) integrating these PRO tools into routine patient care and research studies.

genetics↗

bioRxiv2018

Mobility in Osteogenesis Imperfecta: A Multicenter North American Study

BackgroundOsteogenesis imperfecta (OI) is a genetic connective tissue disorder characterized by increased bone fragility and recurrent fractures. The phenotypic severity of OI has a significant influence on the ability to walk but little is known about the ambulatory characteristics, strength, or functional abilities in individuals with OI, especially in the more severe forms. To advance clinical research in OI, the Linked Clinical Research Centers, network of clinical centers in North America with significant experience in treating patients with OI, was established in 2009. The purpose of this work was to characterize mobility in OI using standard clinical assessment tools. and determine if any patient characteristics could be used to predict mobility outcomes.\n\nMethodsData were collected at five clinical sites and included age, gender, ethnicity, height, weight, use of assistive device, and bisphosphonate use and mobility metrics (age at first walk, Gillette Functional Assessment Questionnaire, Functional Mobility Scale, and distance walked in the 6 minute walk test). Linear mixed models were developed to explore the relationships between subject demographics and mobility metrics.\n\nResultsThe study identified 491 individuals age 3 and older. In general, the results showed minor limitations in the type I group while the more severe types showed more significant limitations in all mobility metrics analyzed. Height and weight were shown to be the most significant predictors of mobility metrics. Relationships with mobility and bisphosphonates varied with OI type and whether oral or IV was used.\n\nConclusionThis paper is the most comprehensive report of mobility in individuals with OI to date. These results are vital to understanding the mobility limitations of specific types of OI and beneficial when developing rehabilitation protocols for this population. It is important for physicians, patients, and caregivers to gain insight into severity and classification of the disease and the influence of disease-related characteristics on the prognosis for mobility.

bioengineering↗