Biology subjects

Lambert, K.

Publications and source records attributed to Lambert, K..

7 recordsLinked to original sources

bioRxiv2025

The U1 snRNP protein U1C and Helix H of U1 snRNA are critical for small molecule splicing modulator function

Risdiplam and branaplam represent two classes of small-molecule splicing modulators that promote U1 snRNP recognition of weak non-canonical GA/GU-containing 5 splice sites (ss). We demonstrated that branaplam enhanced recognition of these 5 ss by reconstituted U1 snRNP in vitro, and that this effect depended on the ZnF domain of U1C and Helix H of U1 snRNA, but not U1A or U1-70K. In cells, depletion of U1C generally reduced compound-induced exon inclusion for most cassette exons. Interestingly, a subset of cassette exons became responsive to compound only upon U1C knockdown, supporting a model in which U1C stabilizes specific conformations at the 5 ss/U1 snRNA interface in a context-dependent manner that can either facilitate or hinder compound binding. Surprisingly, risdiplam shows no effect on weak 5 ss recognition in vitro, suggesting additional cellular factors are required for its activity.

biochemistry↗

bioRxiv2023

Memory Th1 cells modulate heterologous diseases through innate function

Through immune memory, infections have a lasting effect on the host. While memory cells enable accelerated and enhanced responses upon re-challenge with the same pathogen, their impact on susceptibility to unrelated diseases is unclear. We identify a subset of memory T helper 1 (Th1) cells termed innate acting memory T (TIA) cells that originate from a viral infection and produce IFN-{gamma} with innate kinetics upon heterologous challenge in vivo. Activation of memory TIA cells is induced in response to IL-12 in combination with IL-18 or IL-33 but is TCR-independent. Rapid IFN-{gamma} production by memory TIA cells is protective in subsequent heterologous challenge with the bacterial pathogen Legionella pneumophila. In contrast, antigen-independent re-activation of CD4+ memory TIA cells accelerates disease onset in an autoimmune model of multiple sclerosis. Our findings demonstrate that memory Th1 cells can acquire additional TCR-independent functionality to mount rapid, innate-like responses that modulate susceptibility to heterologous challenges.

immunology↗

bioRxiv2021

Permutational immune analysis reveals architectural similarities between inflammaging, Down syndrome and autoimmunity

People with Down syndrome show cellular and clinical features of dysregulated aging of the immune system, including naive-memory shift in the T cell compartment and increased incidence of autoimmunity. However, a quantitative understanding of how various immune compartments change with age in Down syndrome remains lacking. Here we performed deep immunophenotyping of a cohort of individuals with Down syndrome across the lifespan, selecting for individuals not affected by autoimmunity. We simultaneously interrogated age- and sex-matched healthy neurotypical controls and people with type 1 diabetes, as a representative autoimmune disease. We built a new analytical software, IMPACD, that enabled us to rapidly identify many features of immune dysregulation in Down syndrome that are recapitulated in other autoimmune diseases. We found significant quantitative and qualitative dysregulation of naive CD4+ and CD8+ T cells in Down syndrome and identified IL-6 as a candidate driver of some of these changes, thus extending the consideration of immunopathologic cytokines in Down syndrome beyond interferons. Notably, we successfully used immune cellular composition to generate three quantitative models of aging (i.e. immune clocks) trained on control subjects. All three immune clocks demonstrated significantly advanced immune aging in people with Down syndrome. Notably, one of these clocks, informed by Down syndrome-relevant biology, also showed advanced immune aging in people with type 1 diabetes. Together, our findings demonstrate a novel approach to studying immune aging in Down syndrome which may have implications in the context of other autoimmune diseases. One Sentence SummaryPermutational analysis of immune landscape reveals advanced immune aging in people with Down syndrome and in people with type 1 diabetes.

immunology↗

bioRxiv2020

Mu oscillations and motor imagery performance: A reflection of success, not ability

Motor imagery, or our ability to imagine movement without actually engaging in the action, has been an increasingly popular tool in rehabilitation settings. Understanding its neural underpinning is crucial for further development of new interventions. Using scalp electroencephalography (EEG), many studies have shown that mu oscillations (8-13 Hz), a variant of the alpha band recorded over the motor cortex electrodes, are involved in both the imagination and performance of movements; however, the exact relationship between mu oscillations and motor imagery is unclear. To further our understanding of the functional significance of mu oscillations and their role in both motor learning and motor performance, our study sought to investigate how suppression in mu oscillations varies during a motor imagery task according to both within subject imagery success and between subject imagery ability. We examined EEG activity while a large sample of participants performed an objective test of motor imagery ability (Test of Ability in Movement Imagery, TAMI). Results demonstrated that mu oscillatory activity significantly decreased during successful imagery trials as compared to unsuccessful ones. However, the extent of reduction in mu oscillations did not correlate with individual imagery ability. These results provide further support for the involvement of mu oscillations in motor behaviours and indicate that suppression in mu oscillations may serve as an important index for determining successful motor imagery performance within an individual. The processes that underlie this success are likely similar to those that underlie successful motor execution, given motor imagerys proposed functional equivalence to motor imagery.

neuroscience↗

bioRxiv2020

Novel microRNA multivariate biomarkers of response to immunotherapy against HPV E6 oncogene

Cervical cancer is caused by the persistent infection high-risk types of human papillomavirus (HPV) in over 99.9% of cases. To favor malignant transformation, HPV E6 and E7 oncogenes disrupt both p53 and retinoblastoma (Rb) respectively and control microRNA (miR) networks. We have previously demonstrated the therapeutic potential of anti-HPV E6 monoclonal antibodies (mAbs) in experimental models of human cervical cancer; yet the underlying mechanism remains unclear. Here, we sought to determine if anti-HPV E6 mAbs modulate the miR signatures of HPV E6 oncogenes. To this end, we performed qRT-PCR to measure the expression of thirty-four miRs and found that univariate analysis is not able to identify novel interactions characteristic of complex biological systems. Thus, we utilized partial least squares discriminant analysis (PLSDA) to identify signatures of co-varying miRs specific to mAb treatment. These miR signatures predictively discriminate between anti-HPV E6 mAb response and control mAb treatment, which may provide mechanistic insight into the action of anti-HPV E6 mAbs.Competing Interest StatementThe authors have declared no competing interest.View Full Text

systems biology↗

bioRxiv2019

Loss of prdm1a accelerates melanoma onset and progression

Melanoma is an aggressive, deadly skin cancer derived from melanocytes, a neural crest cell derivative. Melanoma cells mirror the developmental program of neural crest cells in that they exhibit the same gene expression patterns and utilize similar cellular mechanisms, including increased cell proliferation, EMT and migration. Here we studied the role of neural crest regulator PRDM1 in melanoma onset and progression. In development, Prdm1a functions to promote neural crest progenitor fate, and in melanoma, we found that PRDM1 has reduced copy number and is recurrently deleted in both zebrafish and humans. When examining expression of neural crest and melanocyte development genes, we show that sox10 progenitor expression is high in prdm1a-/- mutants, while more differentiated melanocyte markers are reduced, suggesting that normally Prdm1a is required for differentiation. Data mining of human melanoma datasets indicate that high PRDM1 expression in human melanoma is correlated with better patient survival and decreased PRDM1 expression is common in metastatic tumors. When one copy of prdm1a is lost in the zebrafish melanoma model (Tg[mitfa:BRAFV600E];p53-/-; prdm1a+ /-), melanoma onset occurs more quickly, and the tumors that form have a larger area with increased expression of sox10. These data demonstrate a novel role for PRDM1 as a tumor suppressor in melanoma.

cancer biology↗

bioRxiv2017

Continuous high-resolution in vivo imaging reveals tumor-specific dissemination in an embryonic zebrafish xenograft model

Mechanisms mediating tumor metastasis are crucial for diagnostic and therapeutic targeting. Here, we take advantage of a transparent embryonic zebrafish xenograft model (eZXM) to visualize and track injected human leukemic and breast cancer cells in real time using selective plane illumination microscopy (SPIM) for up to 30 hours. Injected cells exhibited disease-specific patterns of intravascular distribution with leukemic cells moving faster than breast cancer cells. While breast cancer cells predominantly adhered to nearby regions, about 30% invaded the avascularized tissue, reminiscent of their metastatic phenotype. Survival of the injected tumor cells was partly inhibited by the cellular innate immune system of the recipient embryos and leukemic cell dissemination was effectively inhibited by pharmacological ROCK1 blockade. These observations, and the ability to image several embryos simultaneously, support the use of eZXM and SPIM imaging as a functional screening platform to identify compounds that restricts cancer cell spread and invasion.

cancer biology↗