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Biology subjects

Androphy, E. J.

Publications and source records attributed to Androphy, E. J..

5 recordsLinked to original sources

Spatial transcriptomics identifies dysregulated programs across neural and non-neural tissues in spinal muscular atrophy

Spinal muscular atrophy (SMA) is caused by insufficient levels of the survival motor neuron (SMN) protein and clinically manifests as profound weakness due to motor neuron degeneration. While recent evidence suggests it is a multisystem disorder, the pathological programs in neural and peripheral tissues are poorly understood. We applied spatial transcriptomics to cross-sections from the entire lumbar region of pre-symptomatic SMA and control mice to define early, tissue-wide transcriptional consequences of SMN deficiency. This approach enabled spatially preserved analysis of spinal cord, dorsal root ganglia, muscle, bone, cartilage, bone marrow, adipose, and connective tissues within their native anatomical context. Within the SMA spinal cord, motor neuron associated regions and ventral interneurons exhibited upregulation of neurofilaments, tubulin isoforms, and microtubule transport machinery. Neurofilament changes were largely restricted to motor neurons, and tubulin dysregulation extended broadly across ventral regions. Multiple tissues displayed collagen and extracellular matrix gene dysregulation at post-natal day 4. Skeletal muscle demonstrated fiber type-specific stress responses, including induction of atrophy-associated genes, while bone displayed an osteoclast-dominant transcriptional signature, consistent with accelerated resorption and a pro-osteoporotic state. Bone marrow transcriptomes indicated activation of neutrophil degranulation, innate immune signaling, and osteoclastogenic pathways, identifying bone marrow as an active inflammatory and skeletal regulatory niche in SMA. Adipose tissue exhibited extracellular matrix dysregulation, complement activation, profibrotic TGF-{beta} signaling, and stress-induced lipolysis. These findings reveal that SMN deficiency drives early transcriptional reprogramming across multiple tissues well before motor neuron loss and identify non-neuronal pathological programs that offer therapeutic targets for improving long-term outcomes in SMA.

cell biology↗

E2 displacement of CIP2A from TOPBP1 activates the DNA damage response during papillomavirus life cycles

The papillomavirus life cycle is intricately linked to epithelial differentiation, and the virus manipulates the differentiation process to facilitate viral production. One such manipulation is activation of the DNA damage response (DDR) which promotes viral replication via homologous recombination. This report demonstrates that the papillomavirus transcription/replication/segregation factor E2 activates the DNA damage response (DDR). During differentiation, E2 displacement of CIP2A from TOPBP1 causes CIP2A to bind and inhibit PP2A resulting in DDR activation via ATM phosphorylation. The DDR promotes inhibitory interaction of DBC1 with the class III deacetylase SIRT1, which further boosts the DDR via increased acetylation and stability of viral and host proteins. E2 forms a complex with TOPBP1 and ATM, while preventing ATR activation by blocking TOPBP1-ATR interaction. This "ATM up ATR down" phenotype promotes viral replication via ATM promotion of homologous recombination, and cell proliferation via inhibition of ATR. We demonstrate this mechanism of DDR activation in multiple systems: keratinocytes expressing only E2, in foreskin keratinocytes immortalized by HPV16, in HPV16 positive keratinocytes derived from a cervical lesion, in pre-neoplastic lesions induced by mouse papillomavirus MmuPV1, in head and neck cancer cell lines that retain E2 expression, and in HPV16 positive oropharyngeal patient derived xenografts that retain E2 expression. ATM inhibition preferentially killed cells expressing E2, presenting a novel strategy for treating HPV early preneoplasia and a large subset of HPV+ oropharyngeal cancers retaining E2 expression and episomal genomes.

cancer biology↗

Covalent Inhibition of the Human Papillomavirus Type 16 E6 Protein Restores p53 and Suppresses HPV-Driven Tumorigenesis

High-risk human papillomavirus (HPV) infections are the etiology of approximately 5% of all cancers worldwide, including cervical, anal, and oropharyngeal malignancies. HPV E6 is a multifunctional oncoprotein that drives tumorigenesis and is best known for bridging the ubiquitin ligase E6AP (UBE3A) and p53 into a complex that leads to proteasome mediated destruction of p53. We developed small molecule inhibitors that covalently bind to cysteine-51 (Cys-51) in HPV16 E6. In HPV16-positive cancer cells, these compounds increase p53 protein levels and activate p53-dependent transcriptional programs associated with apoptosis and senescence, resulting in reduced tumor cell viability. In vivo, E6 inhibition suppresses the growth of human HPV16 expressing cervical and oropharyngeal tumor cell lines in mice. The strategy of targeting a viral oncoprotein with a covalent inhibitor demonstrates a genotype-specific therapeutic strategy for HPV-associated cancers and premalignant infections, addressing a significant unmet need in current treatment options.

cancer biology↗

Short duration splice promoting compound enables a tunable mouse model of spinal muscular atrophy

Spinal muscular atrophy (SMA) is a motor neuron disease and the leading cause of infant mortality. SMA results from insufficient survival motor neuron protein (SMN) levels due to alternative splicing. Antisense oligonucleotides, gene therapy and splicing modifiers recently received FDA approval. However, early intervention is required for optimal outcomes, and even continuous treatment maybe insufficient to restore full motor function. Although severe SMA transgenic mouse models have been beneficial for testing therapeutic efficacy, models mimicking milder cases that manifest post-infancy have proven challenging to develop. We have established a titratable model of mild and moderate SMA using the splicing compound NVS-SM2. Administration for 30 days prevented development of the SMA phenotype in severe SMA mice, which typically show rapid weakness and succumb by postnatal day 11. Furthermore, administration at day eight resulted in phenotypic recovery. Remarkably, acute dosing limited to the first three days of life significantly enhanced survival in two severe SMA mice models, easing the burden on neonates and demonstrating the compound as suitable for evaluation of follow-on therapies without potential drug-drug interactions.

neuroscience↗

Optimization of Human Papillomavirus-based Pseudovirus Techniques for Efficient Gene Transfer

Human papillomavirus (HPV) L1 and L2 capsid proteins self-assemble into virions capable of efficiently packaging either its 8 kilobase genome or non-viral DNA. The ability of HPV capsids to package non-viral DNA makes these a useful tool for delivering plasmids to study proteins of interest in a variety of cell types. We describe optimization of current methods and present new protocols for using HPV capsids to deliver non-viral DNA thereby providing an alternative to DNA transfection. Using keratinocyte generated extracellular matrices can enhance infection efficiency in keratinocytes, hepatocytes and neuronal cells. Furthermore, we describe a suspension-based efficient technique for infecting different cell types.

microbiology↗