Biology subjects

Volpatti, J.

Publications and source records attributed to Volpatti, J..

5 recordsLinked to original sources

bioRxiv2022

Selective Control of Parasitic Nematodes Using Bioactivated Nematicides

Parasitic nematodes are a major threat to global food security, particularly as the world amasses 10 billion people amidst limited arable land. Most traditional nematicides have been banned due to poor nematode-selectivity, leaving farmers with inadequate controls. Here, we use the model nematode Caenorhabditis elegans to identify a family of selective imidazothiazole nematicides, called selectivins, that undergo cytochrome p450-dependent bioactivation exclusively in nematodes. At low parts-per-million concentrations, selectivins perform comparably well with commercial nematicides to control root infection by Meloidogyne incognita - the worlds most destructive plant-parasitic nematode. Tests against a wide range of phylogenetically diverse non-target systems demonstrate that selectivins are more nematode-selective than nearly all marketed nematicides. Thus, selectivins are first-in-class bioactivated nematode controls that provide efficacy as well as much-needed nematode selectivity.

pharmacology and toxicology↗

bioRxiv2022

A Nematode-Selective Potentiator of Organophosphate and Carbamate Agrochemicals

Nematode parasites of humans, livestock and crops pose a significant burden on human health and welfare. Alarmingly, parasitic nematodes of animals have rapidly evolved resistance to anthelmintic drugs, and traditional nematicides that protect crops are facing increasing restrictions because of poor phylogenetic selectivity. Here, we present a pipeline that exploits multiple motor outputs of the model nematode C. elegans for nematicide discovery. This pipeline yielded multiple compounds that selectively kill and/or immobilize diverse nematode parasites. We focus on one compound that induces violent convulsions and paralysis that we call Nementin. We find that Nementin agonizes neuronal dense core vesicle release, which in turn agonizes cholinergic signaling. Consequently, Nementin synergistically enhances the potency of widely-used non-selective acetylcholinesterase inhibitors (AChEIs), but in a nematode-selective manner. Nementin therefore has the potential to reduce the environmental impact of toxic AChEI pesticides used to control nematode infections and infestations. Significance StatementParasitic nematodes pose a considerable burden to human health and food security. Small molecules that have traditionally been used to control these parasites have either been banned because of toxicity concerns or are being rendered ineffective because of the evolution of resistance. Significant gaps in our nematicidal toolkit are therefore becoming an alarming problem. Here, we describe our discovery of Nementin, a small molecule that disrupts the nematode nervous system but is ineffective against non-targeted organisms. We find that Nementin also enhances the activity of non-selective pesticides but does so in a nematode-selective manner. Hence, Nementin is an innovative solution to combat parasitic nematodes in a safe and phylum-selective manner. One-Sentence SummaryA C. elegans-based screening pipeline identifies a selective nematicide that also potentiates acetylcholinesterase inhibitors.

pharmacology and toxicology↗

bioRxiv2021

A novel zebrafish model of SPEG-related centronuclear myopathy (CNM): characterization and comparison with other CNM model zebrafish

Centronuclear myopathy (CNM) is a congenital neuromuscular disorder caused by pathogenic variation in genes associated with membrane trafficking and excitation-contraction coupling (ECC). Bi-allelic autosomal recessive mutations in striated muscle enriched protein kinase (SPEG) account for a subset of CNM patients. Previous research has been limited by the perinatal lethality of Speg knockout mice. Thus, the precise biological role of SPEG in skeletal muscle remains unknown. To address this issue, we generated zebrafish spega, spegb, and spega/spegb (speg-DKO) mutant lines. We demonstrate that speg-DKO zebrafish faithfully recapitulate multiple phenotypes associated with human CNM, including disruption of the ECC protein machinery, dysregulation of calcium homeostasis during ECC, and impairment of muscle performance. Taking advantage of the availability of zebrafish models of multiple CNM genetic subtypes, we compared novel and known disease markers in speg-DKO with mtm1-KO and DNM2-S619L transgenic zebrafish. We observed desmin (DES) accumulation common to all CNM subtypes, and DNM2 upregulation in muscle of both speg-DKO and mtm1-KO zebrafish. In all, we establish a new model of SPEG-related CNM, and identify abnormalities in this model suitable for defining disease pathomechanisms and evaluating potential therapies. Summary StatementWe created a novel zebrafish speg mutant model of centronuclear myopathy that recapitulates key features of the human disorder and provides insight into pathomechanisms of the disease.

genetics↗

bioRxiv2021

Natural history of a mouse model of X-linked myotubular myopathy

X-linked myotubular myopathy is a severe monogenetic disorder of the skeletal muscle caused by loss of expression/function mutations in the MTM1 (myotubularin) gene. There is a growing understanding of the pathologic and molecular abnormalities associated with loss of MTM1, and emerging therapeutic strategies that are in the process of translation to patients. Much of these data have been uncovered through experimentation in pre-clinical animal models of the disease. The most widely used model is an Mtm1 gene knockout mouse line; this line faithfully recapitulates the salient genetic and pathologic features of the disease. Despite the advances in aspects of XLMTM, there remain many unknowns related to disease pathomechanisms and to understanding of MTM1s function in normal muscle development, and a continued need for therapy identification and development. To address these barriers, and to lay the groundwork for future study, we performed a natural history study of the Mtm1 knockout mouse model of XLMTM. We show that certain molecular and pathologic changes precede overt phenotypic changes, while others, including abnormalities in triad structure, occur more coincident with muscle weakness in the mouse. In total, we provide a comprehensive longitudinal assessment of molecular and structural features of the murine XLMTM disease process.

genetics↗

bioRxiv2019

Identification of drug modifiers for RYR1 related myopathy using a multi-species discovery pipeline

Ryanodine receptor type I-related myopathies (RYR1-RMs) represent the largest group of non-dystrophic myopathies. RYR1-RMs are associated with severe disabilities and early mortality; despite these facts, there are currently no available treatments. The goal of this study was to identify new therapeutic targets for RYR1-RMs. To accomplish this, we developed a novel discovery pipeline using nematode, zebrafish, and mammalian cell models of the disease. We first performed large-scale drug screens in C. elegans and zebrafish. 74 positive hits were identified in C. elegans, while none were uncovered in the zebrafish. Targeted testing of these hits in zebrafish yielded positive results for two compounds. We examined these compounds using newly created Ryr1 knockout C2C12 cells, and found that p38 inhibition impaired caffeine-induced Ca2+ release. Lastly, we tested one p38 inhibitor in myotubes from Ryr1Y524S/+ (YS) mice, and demonstrated that it blunts the aberrant temperature-dependent increase in resting Ca2+ in these cells. In all, we developed a unique platform for RYR1-RM therapy development that is potentially applicable to a broad range of neuromuscular disorders.

genetics↗