Para-infectious brain injury in COVID-19 persists at follow-up despite attenuated cytokine and autoantibody responses.

To understand neurological complications of COVID-19 better both acutely and for recovery, we measured markers of brain injury, inflammatory mediators, and autoantibodies in 203 hospitalised participants; 111 with acute sera (1-11 days post-admission) and 92 convalescent sera (56 with COVID-19-associated neurological diagnoses). Here we show that compared to 60 uninfected controls, tTau, GFAP, NfL, and UCH-L1 are increased with COVID-19 infection at acute timepoints and NfL and GFAP are significantly higher in participants with neurological complications. Inflammatory mediators (IL-6, IL-12p40, HGF, M-CSF, CCL2, and IL-1RA) are associated with both altered consciousness and markers of brain injury. Autoantibodies are more common in COVID-19 than controls and some (including against MYL7, UCH-L1, and GRIN3B) are more frequent with altered consciousness. Additionally, convalescent participants with neurological complications show elevated GFAP and NfL, unrelated to attenuated systemic inflammatory mediators and to autoantibody responses. Overall, neurological complications of COVID-19 are associated with evidence of neuroglial injury in both acute and late disease and these correlate with dysregulated innate and adaptive immune responses acutely.

Fewer COVID-19 Neurological Complications with Dexamethasone and Remdesivir.

OBJECTIVE: The objective of this study was to assess the impact of treatment with dexamethasone, remdesivir or both on neurological complications in acute coronavirus diease 2019 (COVID-19). METHODS: We used observational data from the International Severe Acute and emerging Respiratory Infection Consortium World Health Organization (WHO) Clinical Characterization Protocol, United Kingdom. Hospital inpatients aged ≥18 years with laboratory-confirmed severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2) infection admitted between January 31, 2020, and June 29, 2021, were included. Treatment allocation was non-blinded and performed by reporting clinicians. A propensity scoring methodology was used to minimize confounding. Treatment with remdesivir, dexamethasone, or both was assessed against the standard of care. The primary outcome was a neurological complication occurring at the point of death, discharge, or resolution of the COVID-19 clinical episode. RESULTS: Out of 89,297 hospital inpatients, 64,088 had severe COVID-19 and 25,209 had non-hypoxic COVID-19. Neurological complications developed in 4.8% and 4.5%, respectively. In both groups, neurological complications were associated with increased mortality, intensive care unit (ICU) admission, worse self-care on discharge, and time to recovery. In patients with severe COVID-19, treatment with dexamethasone (n = 21,129), remdesivir (n = 1,428), and both combined (n = 10,846) were associated with a lower frequency of neurological complications: OR = 0.76 (95% confidence interval [CI] = 0.69-0.83), OR = 0.69 (95% CI = 0.51-0.90), and OR = 0.54 (95% CI = 0.47-0.61), respectively. In patients with non-hypoxic COVID-19, dexamethasone (n = 2,580) was associated with less neurological complications (OR = 0.78, 95% CI = 0.62-0.97), whereas the dexamethasone/remdesivir combination (n = 460) showed a similar trend (OR = 0.63, 95% CI = 0.31-1.15). INTERPRETATION: Treatment with dexamethasone, remdesivir, or both in patients hospitalized with COVID-19 was associated with a lower frequency of neurological complications in an additive manner, such that the greatest benefit was observed in patients who received both drugs together. ANN NEUROL 2023;93:88-102.

Fatal large-vessel cerebrovascular infarct presenting with severe coronavirus disease 2019 in a 39-year-old patient: a case report.

BACKGROUND: Emerging reports are describing stroke in young, otherwise healthy patients with coronavirus disease 2019, consistent with the theory that some of the most serious complications of coronavirus disease 2019 are due to a systemic coagulopathy. However, the relevance of both the severity of coronavirus disease 2019 illness and established vascular risk factors in these younger patients is unknown, as reports are inconsistent. CASE PRESENTATION: Here we describe a 39-year-old white male, who died after presenting simultaneously with a malignant large-vessel cerebrovascular infarct and a critical coronavirus disease 2019 respiratory illness. Doppler ultrasound revealed evidence of carotid plaque thrombosis. Blood tests revealed evidence of undiagnosed diabetes mellitus; however, the patient was otherwise healthy, fit, and active. CONCLUSIONS: This unique case highlights a possible interaction between established risk factors and large-vessel thrombosis in young patients with coronavirus disease 2019, and informs future research into the benefits of anticoagulation in these patients.

Enzyme Fusion Removes Competition for Geranylgeranyl Diphosphate in Carotenogenesis.

Geranylgeranyl diphosphate (GGPP), a prenyl diphosphate synthesized by GGPP synthase (GGPS), represents a metabolic hub for the synthesis of key isoprenoids, such as chlorophylls, tocopherols, phylloquinone, gibberellins, and carotenoids. Protein-protein interactions and the amphipathic nature of GGPP suggest metabolite channeling and/or competition for GGPP among enzymes that function in independent branches of the isoprenoid pathway. To investigate substrate conversion efficiency between the plastid-localized GGPS isoform GGPS11 and phytoene synthase (PSY), the first enzyme of the carotenoid pathway, we used recombinant enzymes and determined their in vitro properties. Efficient phytoene biosynthesis via PSY strictly depended on simultaneous GGPP supply via GGPS11. In contrast, PSY could not access freely diffusible GGPP or time-displaced GGPP supply via GGPS11, presumably due to liposomal sequestration. To optimize phytoene biosynthesis, we applied a synthetic biology approach and constructed a chimeric GGPS11-PSY metabolon (PYGG). PYGG converted GGPP to phytoene almost quantitatively in vitro and did not show the GGPP leakage typical of the individual enzymes. PYGG expression in Arabidopsis resulted in orange-colored cotyledons, which are not observed if PSY or GGPS11 are overexpressed individually. This suggests insufficient GGPP substrate availability for chlorophyll biosynthesis achieved through GGPP flux redirection to carotenogenesis. Similarly, carotenoid levels in PYGG-expressing callus exceeded that in PSY- or GGPS11-overexpression lines. The PYGG chimeric protein may assist in provitamin A biofortification of edible plant parts. Moreover, other GGPS fusions may be used to redirect metabolic flux into the synthesis of other isoprenoids of nutritional and industrial interest.

CRISPR-mediated genotypic and phenotypic correction of a chronic granulomatous disease mutation in human iPS cells.

Chronic granulomatous disease (CGD) is a rare genetic disease characterized by severe and persistent childhood infections. It is caused by the lack of an antipathogen oxidative burst, normally performed by phagocytic cells to contain and clear bacterial and fungal growth. Restoration of immune function can be achieved with heterologous bone marrow transplantation; however, autologous bone marrow transplantation would be a preferable option. Thus, a method is required to recapitulate the function of the diseased gene within the patient's own cells. Gene therapy approaches for CGD have employed randomly integrating viruses with concomitant issues of insertional mutagenesis, inaccurate gene dosage, and gene silencing. Here, we explore the potential of the recently described clustered regularly interspaced short palindromic repeat (CRISPR)-Cas9 site-specific nuclease system to encourage repair of the endogenous gene by enhancing the levels of homologous recombination. Using induced pluripotent stem cells derived from a CGD patient containing a single intronic mutation in the CYBB gene, we show that footprintless gene editing is a viable option to correct disease mutations. Gene correction results in restoration of oxidative burst function in iPS-derived phagocytes by reintroduction of a previously skipped exon in the cytochrome b-245 heavy chain (CYBB) protein. This study provides proof-of-principle for a gene therapy approach to CGD treatment using CRISPR-Cas9.

FtmOx1, a non-heme Fe(II) and alpha-ketoglutarate-dependent dioxygenase, catalyses the endoperoxide formation of verruculogen in Aspergillus fumigatus.

Verruculogen is a tremorgenic mycotoxin and contains an endoperoxide bond. In this study, we describe the cloning, overexpression and purification of a non-heme Fe(ii) and alpha-ketoglutarate-dependent dioxygenase FtmOx1 from Aspergillus fumigatus, which catalyses the conversion of fumitremorgin B to verruculogen by inserting an endoperoxide bond between two prenyl moieties. Incubation with (18)O(2)-enriched atmosphere demonstrated that both oxygen atoms of the endoperoxide bond are derived from one molecule of O(2). FtmOx1 is the first endoperoxide-forming non-heme Fe(ii) and alpha-ketoglutarate-dependent dioxygenase reported so far. A mechanism of FtmOx1-catalysed verruculogen formation is postulated and discussed.

Improved tryprostatin B production by heterologous gene expression in Aspergillus nidulans.

Tryprostatin B, a prenylated diketopiperazine with anti-tubulin activity, has been overproduced in fungal culture by expression of genes of the fumitremorgin cluster from Aspergillus fumigatus in the naïve host Aspergillus nidulans using the alcA promoter. The products of the expressed genes catalyse the first two steps of fumitremorgin biosynthesis, namely the formation of brevianamide F and its conversion to tryprostatin B. Yields of tryprostatin B were up to 250 mg/l, a significant improvement in previously reported levels. This approach illustrates how the availability of fungal genome sequences and knowledge of gene function can be used to achieve the efficient production of biologically active secondary metabolites by genetic manipulation.

Acetylaszonalenin biosynthesis in Neosartorya fischeri. Identification of the biosynthetic gene cluster by genomic mining and functional proof of the genes by biochemical investigation.

Based on the structural information of acetylaszonalenin isolated from Neosartorya fischeri, a putative biosynthetic gene cluster was identified in the genome sequence of this fungus by genomic mining. This cluster consists of three genes coding for a putative non-ribosomal peptide synthetase (AnaPS), a prenyltransferase (AnaPT), and an acetyltransferase (AnaAT). The coding sequences of anaPT and anaAT were cloned in pQE70 and pQE60, respectively, and overexpressed in Escherichia coli. The soluble His(6) fusion proteins were purified to near homogeneity and characterized biochemically. The structures of the enzymatic products were elucidated by NMR and mass spectroscopy analysis. AnaPT was found to catalyze the reverse prenylation of (R)-benzodiazepinedione at position C3 of the indole moiety in the presence of dimethylallyl diphosphate, resulting in formation of aszonalenin. AnaAT was found to catalyze the acetylation of aszonalenin at position N1 of the indoline moiety in the presence of acetyl coenzyme A, resulting in formation of acetylaszonalenin. Km values of AnaPT were determined for dimethylallyl diphosphate at 156 microm and for (R)-benzodiazepinedione at 232 microm. Km values of AnaAT were determined for acetyl coenzyme A at 96 microm and for aszonalenin at 61 microm. The turnover numbers of the AnaPT and AnaAT reactions were determined at 1.5 and 0.14 s(-1), respectively.

Identification of a hybrid PKS/NRPS required for pseurotin A biosynthesis in the human pathogen Aspergillus fumigatus.

The genome sequence of Aspergillus fumigatus revealed the presence of a single hybrid polyketide synthase-non-ribosomal peptide synthetase (PKS/NRPS) gene that is present within a cluster of five genes suggestive of its involvement in secondary metabolism. Here, we present evidence that it is required for the biosynthesis of pseurotin A, a compound with an unusual heterospirocyclic gamma-lactam structure. We have confirmed that the genome reference strain A. fumigatus Af293 produces pseurotin A, a compound previously reported to be a competitive inhibitor of chitin synthase and an inducer of nerve-cell proliferation. Deletion or overexpression of the PKS/NRPS gene psoA in A. fumigatus leads to the absence or accumulation of pseurotin A, respectively; this indicates that this gene is essential for the biosynthesis of pseurotin A. It is likely that the first product of psoA is converted to pseurotin A by the products of other genes in this cluster.

CdpNPT, an N-prenyltransferase from Aspergillus fumigatus: overproduction, purification and biochemical characterisation.

A putative prenyltransferase gene, cdpNPT, was identified in the genome sequence of Aspergillus fumigatus by a homology search by using known prenyltransferases and sequence analysis. CdpNPT consists of 440 amino acids and has a molecular mass of about 50 kDa. The coding sequence of cdpNPT was cloned in pQE60 and overexpressed in E. coli. The soluble His(6)-fusion CdpNPT was purified to near homogeneity and characterised biochemically. The enzyme showed broad substrate specificity towards aromatic substrates and was found to catalyse the prenylation of tryptophan-containing cyclic dipeptides at N1 of the indole moieties in the presence of dimethylallyl diphosphate (DMAPP); geranyl diphosphate was not accepted as prenyl donor. The structures of the enzymatic products were elucidated by NMR and MS analysis. The K(m) value for DMAPP was determined to be 650 microM. Due to substrate inhibition, K(m) values could not be obtained for the aromatic substrates. CdpNPT does not need divalent metal ions for its enzymatic reaction, although Ca(2+) enhances the reaction velocity by up to the threefold. CdpNPT is the first N-prenyltransferase that has been purified and characterised in a homogenous form after heterologous overproduction. Interestingly, it shows significant sequence similarity to other indole prenyltransferases that catalyse the formation of C--C bonds.

The fumitremorgin gene cluster of Aspergillus fumigatus: identification of a gene encoding brevianamide F synthetase.

A gene encoding a putative dimodular nonribosomal peptide synthetase (NRPS) was identified within a gene cluster of Aspergillus fumigatus, a species reported to produce fumitremorgins and other prenylated alkaloids. The gene was deleted and overexpressed in the genome reference strain Af293, and was also expressed in the naïve host Aspergillus nidulans, which lacks the equivalent gene cluster. While neither fumitremorgins nor the dipeptide brevianamide F (cyclo-L-Trp-L-Pro), an early intermediate, were detected in wild-type and deletion strains of A. fumigatus, brevianamide F accumulated in fungal cultures following increased expression of the NRPS gene in both A. fumigatus and A. nidulans. We conclude that the gene Afu8g00170, named ftmA, encodes the NRPS brevianamide synthetase. Brevianamide F is the precursor of a variety of fungal prenylated alkaloids with biological activity, including fumitremorgins A, B and C and tryprostatin B.

Overproduction, purification and characterization of FtmPT1, a brevianamide F prenyltransferase from Aspergillus fumigatus.

A putative prenyltransferase gene, ftmPT1, was identified in the genome sequence of Aspergillus fumigatus. ftmPT1 was cloned and expressed in Escherichia coli, and the protein FtmPT1 was purified to near homogeneity and characterized biochemically. This enzyme was found to catalyse the prenylation of cyclo-L-trp-L-Pro (brevianamide F) at the C-2 position of the indole nucleus. FtmPT1 is a soluble monomeric protein, which does not contain the usual prenyl diphosphate binding site (N/D)DXXD found in most prenyltransferases, and which does not require divalent metal ions for its enzymic activity. K(m) values for brevianamide F and dimethylallyl diphosphate were determined as 55 and 74 microM, respectively. The turnover number was 5.57 s(-1). FtmPT1 showed a high substrate specificity towards dimethylallyl diphosphate, but accepted different tryptophan-containing cyclic dipeptides. Together with dimethylallyltryptophan synthase of ergot alkaloid biosynthesis, FtmPT1 belongs to a new group of prenyltransferases with aromatic substrates.