Reimer, B. | Search bioRxiv

bioRxiv2024

Discovery of a novel albendazole-ivermectin refractory Trichuris species, T. hominis, in C&ocircte d'Ivoire patients through fecal DNA metabarcoding

Albendazole-ivermectin combination therapy is a promising alternative to benzimidazole monotherapy for Trichuris trichiura control. We used fecal DNA metabarcoding to genetically characterize Trichuris populations in patients from a clinical trial showing lower albendazole-ivermectin efficacy in Cote dIvoire (ERR below 70%) than in Lao PDR and Tanzania (ERR above 98%). ITS-1 and ITS-2 rDNA metabarcoding revealed the entire Cote dIvoire Trichuris population was phylogenetically distinct from T. trichiura in Lao PDR and Tanzania, and more closely related to the porcine parasite Trichuris suis. Complete mitogenomes of eight adult Trichuris from Cote dIvoire confirmed their species-level differentiation. Corresponding Trichuris ITS-1 and ITS-2 sequences in NCBI from individual human patients in Cameroon and Uganda and three captive non-human primates suggest this newly recognized species, T. incognita, is distributed beyond Cote dIvoire and has zoonotic potential. Further work is needed to assess the impact of this Trichuris species on soil transmitted helminth control programs.

genomics↗

bioRxiv2022

Effectors enabling adaptation to mitochondrial complex I loss in Hurthle cell carcinoma

Oncocytic (Hurthle cell) carcinoma of the thyroid (HCC) is genetically characterized by complex I mitochondrial DNA mutations and widespread chromosomal losses. Here, we utilize RNA-seq and metabolomics to identify candidate molecular effectors activated by these genetic drivers. We find glutathione biosynthesis, amino acid metabolism, mitochondrial unfolded protein response, and lipid peroxide scavenging, a safeguard against ferroptosis, to be increased in HCC. A CRISPR-Cas9 knockout screen in a new HCC model reveals which pathways are key for fitness, and highlights loss of GPX4, a defense against ferroptosis, as a strong liability. Rescuing complex I redox activity with the yeast NADH dehydrogenase (NDI1) in HCC cells diminishes ferroptosis sensitivity, while inhibiting complex I in normal thyroid cells augments ferroptosis induction. Our work demonstrates unmitigated lipid peroxide stress to be an HCC vulnerability that is mechanistically coupled to the genetic loss of mitochondrial complex I activity. SignificanceOncocytic (Hurthle cell) carcinoma of the thyroid (HCC) is a unique tumor with a remarkable accumulation of mitochondria. HCC harbors unique genetic alterations, including mitochondrial DNA (mtDNA) mutations in complex I genes and widespread loss-of-heterozygosity in the nuclear DNA. With less favorable clinical outcomes, new therapies for HCC are needed, especially since these tumors show intrinsic resistance to radioactive iodine, which is one of the main treatments for metastatic well-differentiated thyroid cancer. An absence of authentic HCC cell lines and animal models has hindered the mechanistic understanding of this disease and slowed therapeutic progress. In this study, we describe the transcriptomic and metabolomic landscape of HCC and present new HCC models that recapitulate key mtDNA and nuclear DNA alterations. A targeted CRISPR-Cas9 knockout screen in an HCC cell line highlights the molecular programs nominated by our -omics profiling that are required for cell fitness. This screen suggests that lipid peroxide scavenging, a defense system against an iron-dependent form of cell death known as ferroptosis, is a vulnerability in HCC that is coupled to complex I loss, and that targeting this pathway may help patients with HCC.

cancer biology↗