scholarly journals Coronavirus infection and PARP expression dysregulate the NAD metabolome: An actionable component of innate immunity

2020 ◽  
Vol 295 (52) ◽  
pp. 17986-17996 ◽  
Author(s):  
Collin D. Heer ◽  
Daniel J. Sanderson ◽  
Lynden S. Voth ◽  
Yousef M. O. Alhammad ◽  
Mark S. Schmidt ◽  
...  

Poly(ADP-ribose) polymerase (PARP) superfamily members covalently link either a single ADP-ribose (ADPR) or a chain of ADPR units to proteins using NAD as the source of ADPR. Although the well-known poly(ADP-ribosylating) (PARylating) PARPs primarily function in the DNA damage response, many noncanonical mono(ADP-ribosylating) (MARylating) PARPs are associated with cellular antiviral responses. We recently demonstrated robust up-regulation of several PARPs following infection with murine hepatitis virus (MHV), a model coronavirus. Here we show that SARS-CoV-2 infection strikingly up-regulates MARylating PARPs and induces the expression of genes encoding enzymes for salvage NAD synthesis from nicotinamide (NAM) and nicotinamide riboside (NR), while down-regulating other NAD biosynthetic pathways. We show that overexpression of PARP10 is sufficient to depress cellular NAD and that the activities of the transcriptionally induced enzymes PARP7, PARP10, PARP12 and PARP14 are limited by cellular NAD and can be enhanced by pharmacological activation of NAD synthesis. We further demonstrate that infection with MHV induces a severe attack on host cell NAD+ and NADP+. Finally, we show that NAMPT activation, NAM, and NR dramatically decrease the replication of an MHV that is sensitive to PARP activity. These data suggest that the antiviral activities of noncanonical PARP isozyme activities are limited by the availability of NAD and that nutritional and pharmacological interventions to enhance NAD levels may boost innate immunity to coronaviruses.

Author(s):  
Collin D. Heer ◽  
Daniel J. Sanderson ◽  
Lynden S. Voth ◽  
Yousef M.O. Alhammad ◽  
Mark S. Schmidt ◽  
...  

ABSTRACTPoly-ADP-ribose polymerase (PARP) superfamily members covalently link either a single ADP-ribose (ADPR) or a chain of ADPR units to proteins using nicotinamide adenine dinucleotide (NAD) as the source of ADPR. While the well-known poly-ADP-ribosylating (PARylating) PARPs primarily function in the DNA damage response, many non-canonical mono-ADP-ribosylating (MARylating) PARPs are associated with cellular antiviral responses. We recently demonstrated robust upregulation of several PARPs following infection with Murine Hepatitis Virus (MHV), a model coronavirus. Here we show that SARS-CoV-2 infection strikingly upregulates MARylating PARPs and induces the expression of genes encoding enzymes for salvage NAD synthesis from nicotinamide (NAM) and nicotinamide riboside (NR), while downregulating other NAD biosynthetic pathways. We show that overexpression of PARP10 is sufficient to depress cellular NAD and that the activities of the transcriptionally induced enzymes PARP7, PARP10, PARP12 and PARP14 are limited by cellular NAD and can be enhanced by pharmacological activation of NAD synthesis. We further demonstrate that infection with MHV induces a severe attack on host cell NAD+ and NADP+. Finally, we show that NAMPT activation, NAM and NR dramatically decrease the replication of an MHV virus that is sensitive to PARP activity. These data suggest that the antiviral activities of noncanonical PARP isozyme activities are limited by the availability of NAD, and that nutritional and pharmacological interventions to enhance NAD levels may boost innate immunity to coronaviruses.


2007 ◽  
Vol 81 (19) ◽  
pp. 10280-10291 ◽  
Author(s):  
Damon J. Deming ◽  
Rachel L. Graham ◽  
Mark R. Denison ◽  
Ralph S. Baric

ABSTRACT Coronaviruses express open reading frame 1a (ORF1a) and ORF1b polyproteins from which 16 nonstructural proteins (nsp) are derived. The highly conserved region at the carboxy terminus of ORF1a is processed by the nsp5 proteinase (Mpro) into mature products, including nsp7, nsp8, nsp9, and nsp10, proteins with predicted or identified activities involved in RNA synthesis. Although continuous translation and proteolytic processing of ORF1ab by Mpro is required for replication, it is unknown whether specific cleavage events within the polyprotein are dispensable. We determined the requirement for the nsp7 to nsp10 proteins and their processing during murine hepatitis virus (MHV) replication. Through use of an MHV reverse genetics system, in-frame deletions of the coding sequences for nsp7 to nsp10, or ablation of their flanking Mpro cleavage sites, were made and the effects upon replication were determined. Viable viruses were characterized by analysis of Mpro processing, RNA transcription, and growth fitness. Deletion of any of the regions encoding nsp7 to nsp10 was lethal. Disruption of the cleavage sites was lethal with the exception of that of the nsp9-nsp10 site, which resulted in a mutant virus with attenuated replication. Passage of the attenuated nsp9-nsp10 cleavage mutant increased fitness to near-wild-type kinetics without reversion to a virus capable of processing nsp9-nsp10. We also confirmed the presence of a second cleavage site between nsp7 and nsp8. In order to determine whether a distinct function could be attributed to preprocessed forms of the polyprotein, including nsp7 to nsp10, the genes encoding nsp7 and nsp8 were rearranged. The mutant virus was not viable, suggesting that the uncleaved protein may be essential for replication or proteolytic processing.


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Yuxin Fan ◽  
Jiayu Peng ◽  
Jiacheng Wu ◽  
Ping Zhou ◽  
Ruijie He ◽  
...  

Abstract Background Flavonoid biosynthesis in plants is primarily regulated at the transcriptional level by transcription factors modulating the expression of genes encoding enzymes in the flavonoid pathway. One of the most studied transcription factor complexes involved in this regulation consists of a MYB, bHLH and WD40. However, in Chinese Narcissus (Narcissus tazetta L. var. chinensis), a popular monocot bulb flower, the regulatory mechanism of flavonoid biosynthesis remains unclear. Results In this work, genes related to the regulatory complex, NtbHLH1 and a R2R3-MYB NtMYB6, were cloned from Chinese Narcissus. Phylogenetic analysis indicated that NtbHLH1 belongs to the JAF13 clade of bHLH IIIf subgroup, while NtMYB6 was highly homologous to positive regulators of proanthocyanidin biosynthesis. Both NtbHLH1 and NtMYB6 have highest expression levels in basal plates of Narcissus, where there is an accumulation of proanthocyanidin. Ectopic over expression of NtbHLH1 in tobacco resulted in an increase in anthocyanin accumulation in flowers, and an up-regulation of expression of the endogenous tobacco bHLH AN1 and flavonoid biosynthesis genes. In contrast, the expression level of LAR gene was significantly increased in NtMYB6-transgenic tobacco. Dual luciferase assays showed that co-infiltration of NtbHLH1 and NtMYB6 significantly activated the promoter of Chinese Narcissus DFR gene. Furthermore, a yeast two-hybrid assay confirmed that NtbHLH1 interacts with NtMYB6. Conclusions Our results suggest that NtbHLH1 may function as a regulatory partner by interacting directly with NtMYB6 to enhance proanthocyanidin accumulation in Chinese Narcissus.


2021 ◽  
Vol 10 (14) ◽  
pp. 3058
Author(s):  
Aleksandra Mielczarek-Palacz ◽  
Celina Kruszniewska-Rajs ◽  
Marta Smycz-Kubańska ◽  
Jarosław Strzelczyk ◽  
Wojciech Szanecki ◽  
...  

The aim of the analysis was for the first time to assess the expression of genes encoding IL-21 and IL-22 at the mRNA level in ovarian tumor specimens and the concentration of these parameters in serum and peritoneal fluid in patients with ovarian serous cancer. The levels of IL-21 and IL-22 transcripts were evaluated with the use of the real-time RT-qPCR. Enzyme-linked immunosorbent assay (ELISA) was used to determine the concentration of proteins. Quantitative analysis of IL-21 gene mRNA in the tumor tissue showed the highest activity in the G1 degree of histopathological differentiation and was higher in G1 compared to the control group. The concentration of IL-21 and IL-22 in the serum and in the peritoneal fluid of women with ovarian cancer varied depending on the degree of histopathological differentiation of the cancer and showed statistical variability compared to controls. The conducted studies have shown that the local and systemic changes in the immune system involving IL-21 and IL-22 indicate the participation of these parameters in the pathogenesis of ovarian cancer, and modulation in the IL-21/IL-22 system may prove useful in the development of new diagnostic and therapeutic strategies used in patients, which require further research.


2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Amber R Paulson ◽  
Maureen O’Callaghan ◽  
Xue-Xian Zhang ◽  
Paul B Rainey ◽  
Mark R H Hurst

Abstract The function of microbes can be inferred from knowledge of genes specifically expressed in natural environments. Here, we report the in vivo transcriptome of the entomopathogenic bacterium Yersinia entomophaga MH96, captured during initial, septicemic, and pre-cadaveric stages of intrahemocoelic infection in Galleria mellonella. A total of 1285 genes were significantly upregulated by MH96 during infection; 829 genes responded to in vivo conditions during at least one stage of infection, 289 responded during two stages of infection, and 167 transcripts responded throughout all three stages of infection compared to in vitro conditions at equivalent cell densities. Genes upregulated during the earliest infection stage included components of the insecticidal toxin complex Yen-TC (chi1, chi2, and yenC1), genes for rearrangement hotspot element containing protein yenC3, cytolethal distending toxin cdtAB, and vegetative insecticidal toxin vip2. Genes more highly expressed throughout the infection cycle included the putative heat-stable enterotoxin yenT and three adhesins (usher-chaperone fimbria, filamentous hemagglutinin, and an AidA-like secreted adhesin). Clustering and functional enrichment of gene expression data also revealed expression of genes encoding type III and VI secretion system-associated effectors. Together these data provide insight into the pathobiology of MH96 and serve as an important resource supporting efforts to identify novel insecticidal agents.


2020 ◽  
Vol 7 (1) ◽  
Author(s):  
Shaohuang Shen ◽  
Guan Wang ◽  
Ming Zhang ◽  
Yin Tang ◽  
Yang Gu ◽  
...  

Abstract Hexanol–butanol–ethanol fermentation from syngas by Clostridium carboxidivorans P7 is a promising route for biofuel production. However, bacterial agglomeration in the culture of 37 °C severely hampers the accumulation of biomass and products. To investigate the effect of culture temperature on biomass growth and higher-alcohol production, C. carboxidivorans P7 was cultivated at both constant and two-step temperatures in the range from 25 to 37 °C. Meanwhile, Tween-80 and saponin were screened out from eight surfactants to alleviate agglomeration at 37 °C. The results showed that enhanced higher-alcohol production was contributed mainly by the application of two-step temperature culture rather than the addition of anti-agglomeration surfactants. Furthermore, comparative transcriptome revealed that although 37 °C promoted high expression of genes involved in the Wood–Ljungdahl pathway, genes encoding enzymes catalyzing acyl-condensation reactions associated with higher-alcohol production were highly expressed at 25 °C. This study gained greater insight into temperature-effect mechanism on syngas fermentation by C. carboxidivorans P7.


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