Prospective assessment of humoral and cellular immune responses to a 3rd COVID-19 mRNA vaccine dose among immunocompromised individuals.

BACKGROUND: Improved COVID-19 prevention is needed for immunocompromised individuals. METHODS: Prospective study of healthcare workers (HCW) and immunocompromised participants with baseline serology following 2 mRNA vaccines and who were retested after dose 3 (D3); multivariable regression was used to identify predictors of serological responses. IFNγ/TNFα T-cell responses were assessed in a subset. RESULTS: 536 participants were included: 492 immunocompromised [(206 solid organ transplant (SOT), 128 autoimmune, 80 hematologic malignancy (HM), 48 solid tumor, 25 HIV], 44 HCW. D3 significantly increased Spike IgG levels among all, but SOT and HM participants had the lowest median antibody levels post-D3 (increase from 0.09 to 0.83 and 0.27 to 1.92, respectively), versus HCW and persons with HIV, autoimmune conditions, and solid tumors (increases from 4.44 to 19.79, 2.9 to 15.75, 3.82 to 16.32, and 4.1 to 25.54, respectively). Seropositivity post-D3 was lowest for SOT (49.0%) and HM (57.8%), versus others (>90% seropositive). Neutralization post-D3 was lowest among SOT and HM. Predictors of lower antibody levels included low baseline levels and shorter intervals between vaccines. T-cell responses against Spike increased significantly among HCW and non-significantly among immunocompromised individuals. CONCLUSIONS: D3 significantly improves serological but not T-cell responses among immunocompromised individuals. SOT and HM patients have suboptimal responses to D3.

A defect in molybdenum cofactor binding causes an attenuated form of sulfite oxidase deficiency.

Isolated sulfite oxidase deficiency (ISOD) is a rare recessive and infantile lethal metabolic disorder, which is caused by functional loss of sulfite oxidase (SO) due to mutations of the SUOX gene. SO is a mitochondrially localized molybdenum cofactor (Moco)- and heme-dependent enzyme, which catalyzes the vital oxidation of toxic sulfite to sulfate. Accumulation of sulfite and sulfite-related metabolites such as S-sulfocysteine (SSC) are drivers of severe neurodegeneration leading to early childhood death in the majority of ISOD patients. Full functionality of SO is dependent on correct insertion of the heme cofactor and Moco, which is controlled by a highly orchestrated maturation process. This maturation involves the translation in the cytosol, import into the intermembrane space (IMS) of mitochondria, cleavage of the mitochondrial targeting sequence, and insertion of both cofactors. Moco insertion has proven as the crucial step in this maturation process, which enables the correct folding of the homodimer and traps SO in the IMS. Here, we report on a novel ISOD patient presented at 17 months of age carrying the homozygous mutation NM_001032386.2 (SUOX):c.1097G > A, which results in the expression of SO variant R366H. Our studies show that histidine substitution of Arg366, which is involved in coordination of the Moco-phosphate, causes a severe reduction in Moco insertion efficacy in vitro and in vivo. Expression of R366H in HEK SUOX-/- cells mimics the phenotype of patient's fibroblasts, representing a loss of SO expression and specific activity. Our studies disclose a general paradigm for a kinetic defect in Moco insertion into SO caused by residues involved in Moco coordination resulting in the case of R366H in an attenuated form of ISOD.

Delineating the phenotypic spectrum of sulfite oxidase and molybdenum cofactor deficiency.

OBJECTIVE: To define the phenotypic spectrum of isolated sulfite oxidase (ISOD) and molybdenum cofactor deficiency (MoCD), aiming to promote timely diagnosis and assist in future clinical trial design. METHODS: We analyzed clinical, radiographic, biochemical, and genetic data from 146 patients reported in the literature. RESULTS: We stratified patients into 2 phenotypic subgroups based on clinical and radiographic characteristics. In the first (Class I), patients presented early in life (age 1-50 days) with acute onset of neurologic symptoms and development of diffuse brain injury with cystic leukomalacia. Patients in the second subgroup (Class II) presented later in life (age 30 days-23 years) with prominent movement abnormalities and selective injury of the basal ganglia and cerebellum. A significant difference in survival estimates correlated with milder disease severity among Class II patients. Substantial overlap in sulfur-containing metabolite levels prevented discrimination of subgroups based on diagnostic biomarkers, but genotype-phenotype correlations suggested that residual SUOX activity may contribute to milder phenotypes. CONCLUSIONS: Patients with SUOX and MoCD gravitate toward 1 of 2 distinct clinicoradiographic profiles. Patient stratification may help promote accurate diagnosis, prognostication, and aid in the design of future clinical trials.

Sulfite Alters the Mitochondrial Network in Molybdenum Cofactor Deficiency.

Molybdenum cofactor deficiency (MoCD) is an autosomal recessive disorder belonging to the large family of inborn errors in metabolism. Patients typically present with encephalopathy and seizures early after birth and develop severe neurodegeneration within the first few weeks of life. The main pathomechanism underlying MoCD is the loss of function of sulfite oxidase (SO), a molybdenum cofactor (Moco) dependent enzyme located in mitochondrial intermembrane space. SO catalyzes the oxidation of sulfite (SO3 2-) to sulfate (SO4 2-) in the terminal reaction of cysteine catabolism, and in the absence of its activity, sulfurous compounds such as SO3 2-, S-sulfocysteine, and thiosulfate accumulate in patients. Despite growing evidence that these compounds affect neuronal and mitochondrial function, the molecular basis of neuronal dysfunction and cell death in MoCD is still poorly understood. Here we show that mitochondria are severely affected by the loss of SO activity. SO-deficient mouse embryonic fibroblasts display reduced growth rates and impaired ATP production when cultured in galactose, which is an indicator of mitochondrial dysfunction. We also found that mitochondria in SO-deficient cells form a highly interconnected network compared to controls while displaying a slight decrease in motility and unchanged mitochondrial mass. Moreover, we show that the mitochondrial network is directly influenced by SO3 2-, as a moderate elevation of SO3 2- lead to the formation of an interconnected mitochondrial network, while high SO3 2- levels induced fragmentation. Finally, we found a highly interconnected mitochondrial network in MoCD patient-derived fibroblasts, similar to our findings in mouse-derived fibroblasts. We therefore conclude that altered mitochondrial dynamics are an important contributor to the disease phenotype and suggest that MoCD should be included among the mitochondrial disorders.

Selective Persulfide Detection Reveals Evolutionarily Conserved Antiaging Effects of S-Sulfhydration.

Life on Earth emerged in a hydrogen sulfide (H2S)-rich environment eons ago and with it protein persulfidation mediated by H2S evolved as a signaling mechanism. Protein persulfidation (S-sulfhydration) is a post-translational modification of reactive cysteine residues, which modulate protein structure and/or function. Persulfides are difficult to label and study due to their reactivity and similarity with cysteine. Here, we report a facile strategy for chemoselective persulfide bioconjugation using dimedone-based probes, to achieve highly selective, rapid, and robust persulfide labeling in biological samples with broad utility. Using this method, we show persulfidation is an evolutionarily conserved modification and waves of persulfidation are employed by cells to resolve sulfenylation and prevent irreversible cysteine overoxidation preserving protein function. We report an age-associated decline in persulfidation that is conserved across evolutionary boundaries. Accordingly, dietary or pharmacological interventions to increase persulfidation associate with increased longevity and improved capacity to cope with stress stimuli.

Two Novel Negative-Sense RNA Viruses Infecting Grapevine Are Members of a Newly Proposed Genus within the Family Phenuiviridae.

Two novel negative-stranded (ns)RNA viruses were identified by high throughput sequencing in grapevine. The genomes of both viruses, named grapevine Muscat rose virus (GMRV) and grapevine Garan dmak virus (GGDV), comprise three segments with each containing a unique gene. Based on sequence identity and presence of typical domains/motifs, the proteins encoded by the two viruses were predicted to be: RNA-dependent RNA polymerase (RdRp), nucleocapsid protein (NP), and putative movement protein (MP). These proteins showed the highest identities with orthologs in the recently discovered apple rubbery wood viruses 1 and 2, members of a tentative genus (Rubodvirus) within the family Phenuiviridae. The three segments of GMRV and GGDV share almost identical sequences at their 5' and 3' termini, which are also complementary to each other and may form a panhandle structure. Phylogenetics based on RdRp, NP and MP placed GMRV and GGDV in the same cluster with rubodviruses. Grapevine collections were screened for the presence of both novel viruses via RT-PCR, identifying infected plants. GMRV and GGDV were successfully graft-transmitted, thus, they are the first nsRNA viruses identified and transmitted in grapevine. Lastly, different evolutionary scenarios of nsRNA viruses are discussed.

Homeostatic impact of sulfite and hydrogen sulfide on cysteine catabolism.

Cysteine is one of the two key sulfur-containing amino acids with important functions in redox homeostasis, protein functionality and metabolism. Cysteine is taken up by mammals via their diet and can also be derived from methionine via the transsulfuration pathway. The cellular concentration of cysteine is kept within a narrow range by controlling its synthesis and degradation. There are two pathways for the catabolism of cysteine leading to sulfate, taurine and thiosulfate as terminal products. The oxidative pathway produces taurine and sulfate, while the H2 S pathway involves different enzymatic reactions leading to the formation and clearance of H2 S, an important signalling molecule in mammals, resulting in thiosulfate and sulfate. Sulfite is a common intermediate in both catabolic pathways. Sulfite is considered as cytotoxic and produces neurotoxic S-sulfonates. As a result, a deficiency in the terminal steps of cysteine or H2 S catabolism leads to severe forms of encephalopathy with the accumulation of sulfite and H2 S in the body. This review links the homeostatic regulation of both cysteine catabolic pathways to sulfite and H2 S. LINKED ARTICLES: This article is part of a themed section on Chemical Biology of Reactive Sulfur Species. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v176.4/issuetoc.

Distribution of Kroeyerina elongata (Kroyeriidae: Siphonostomatoida, Copepoda) in the olfactory sacs of the blue shark, Prionace glauca.

The infection pattern of Kroeyerina elongata (Kroyeriidae, Copepoda) in the olfactory sacs of the blue shark, Prionace glauca, was investigated using 4,722 copepods from 54 olfactory sacs. Copepod prevalence and mean intensity of infection per olfactory sac were 94.0 and 91.1%, respectively, and the most intensely infected olfactory sac and shark hosted 218 and 409 copepods, respectively. There were significant linear relationships between the number of female and total copepods per left olfactory sac and shark fork length as well as between the numbers of female, male, and total copepods per shark and mean olfactory sac width and cumulative olfactory sac width. Female copepods typically outnumbered males within olfactory sacs (mean intensity  =  65.7 and 26.3, respectively), and no statistical differences were detected between the numbers of copepods inhabiting the left and right olfactory sacs. Copepods were not evenly distributed within olfactory sacs. Typically, female copepods occupied olfactory chambers located centrally along the length of the olfactory sac, while males infected lateral olfactory chambers nearest the naris. The orientation of most copepods (84.6%) suggested positive rheotaxis relative to the path of water through the olfactory sac. Within olfactory chambers, most mature females (68.2%) infected the first third of the peripheral excurrent channel and the adjacent fringe of olfactory lamellae, while most males (91.7%) infected the olfactory lamellae, and the 4 larval females collected were attached within the lamellar field and grasped by males. Based on the observed infection patterns and the pattern of water flow throughout the olfactory sac, a hypothesis regarding the life cycle of K. elongata is advanced wherein infective copepodids are swept into the olfactory sac from the surrounding sea and initially colonize the olfactory lamellae. Copepodids feed and mature among the olfactory lamellae, and adult males search for mates and copulate with young females among the olfactory lamellae. Inseminated females move to the peripheral excurrent channels to mature and produce ovisacs. Hatching ovisacs release free-swimming nauplii into the excurrent water flow to be swept into the milieu, where they can molt into infective copepodids that may infect new hosts.