Nei-like DNA glycosylase 2 selectively antagonizes interferon-β expression upon respiratory syncytial virus infection

Low levels of DNA repair enzyme NEIL2 May exacerbate inflammation and genomic damage in subjects with stable COPD and during severe exacerbations

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is a chronic inflammatory airway disease that is an independent risk factor for lung cancer. Reduction in NEIL2 function, a DNA glycosylase involved in DNA repair during transcription, has been associated with an increased incidence of malignancies in humans. NEIL2 knockout mouse models have demonstrated increased inflammation and oxidative DNA damage in the lungs after exposure to an inflammatory insult, but data are lacking regarding NEIL2 function in individuals with COPD. We investigated whether NEIL2 levels and oxidative DNA damage to the transcribed genome are reduced in individuals with stable COPD and during severe acute exacerbations of COPD (AECOPD).

METHODS

The study was conducted at a single center in the US. Eligible subjects underwent a one-time 30 cc venous blood draw. The population consisted of 50 adults: 16 with stable COPD, 11 hospitalized for AECOPD, and 23 individuals without lung disease (controls). We analyzed blood leukocytes for NEIL2 mRNA and DNA damage by RT‒qPCR and LA‒qPCR, respectively, in all groups. Plasma levels of seven biomarkers, CXCL1, CXCL8, CXCL9, CXCL10, CCL2, CCL11 and IL-6, were analyzed in the COPD groups using a magnetic bead panel (Millipore®).

RESULTS

The fold change in NEIL2 mRNA levels were lower in individuals with stable COPD and AECOPD than in controls (0.72 for COPD, p = 0.029; 0.407 for AECOPD, p < 0.001). The difference in NEIL2 mRNA expression between the stable COPD group and AECOPD group was also statistically significant (p < 0.001). The fold change in DNA lesions per 10 kb of DNA was greater in the stable COPD (9.38, p < 0.001) and AECOPD (15.81, p < 0.001) groups than in the control group. The difference in fold change was also greater in the AECOPD group versus stable COPD p < 0.024). Cytokine levels were not significantly different between the COPD groups. NEIL2 levels were correlated with plasma eosinophil levels in the stable COPD group (r = 0.737, p = 0.003).

CONCLUSIONS

NEIL2 mRNA levels are significantly reduced in individuals with COPD and may exacerbate DNA damage and inflammation. These results suggest a possible mechanism that increases inflammation and oxidative genomic damage in COPD.

CLINICAL TRIAL NUMBER

Not applicable.

DNA repair and disease: insights from the human DNA glycosylase NEIL family

The base excision repair pathway protects DNA from base damage via oxidation, deamination, alkylation and methylation. DNA glycosylases are key enzymes that recognize damaged bases in a lesion-specific manner and initiate the base excision repair process. Among these, the endonuclease VIII-like 1-3 (NEIL1-3) family, which is found in mammalian genomes, is a homolog of bacterial DNA glycosylases known as Fpg/Nei. NEIL enzymes have similar structures and substrates but with slight differences. When repair proteins are impaired, the accumulation of damaged bases can lead to increased genomic instability, which is implicated in various pathologies, including cancer and neurodegeneration. Notably, mutations in these proteins also influence a range of other diseases and inflammation. This review focuses on the influence of the NEIL family on human health across different organ systems. Investigating the relationship between NEIL mutations and diseases can improve our understanding of how these enzymes affect the human body. This information is crucial for understanding the basic mechanisms of DNA repair and enabling the development of novel inhibitors or gene therapies that target only these enzymes. Understanding the role of the NEIL family provides insights into novel therapies and improves our ability to combat genetic diseases.

NEIL1 block IFN-β production and enhance vRNP function to facilitate influenza A virus proliferation

Influenza A virus (IAV) has developed multiple tactics to hinder the innate immune response including the epigenetic regulation during IAV infection, but the novel epigenetic factors and their mechanism in innate immunity remain well studied. Here, through a non-biased high-throughput sgRNA screening of 1041 known epigenetic modifiers in a cellular model of IAV-induced interferon-beta (IFN-β) production, we identified nei endonuclease VIII-like 1 (NEIL1) as a critical regulator of IFN-β in response to viral infection. Further studies showed that NEIL1 promoted the replication of the influenza virus by regulating the methylation of cytonuclear IFN-β promoter (mainly CpG-345), inhibiting the expression of IFN-β and IFN-stimulating genes. The structural domains of NEIL1, especially the catalytic domain, were critical for the suppression of IFN-β production, but the enzymatic activity of NEIL1 was dispensable. Furthermore, our results revealed that NEIL1 relied on interactions with the N- and C-terminus of the nucleoprotein (NP) of IAV, and NEIL1 expression facilitated the entry of the NP into the nucleus, which further enhanced the stability of the viral ribonucleoprotein (vRNP) complex and thus contributed to IAV replication and transcription. These findings reveal an enzyme-independent mechanism of host NEIL1 that negatively regulates IFN-β expression, thereby facilitating IAV propagation. Our study provides new insights into the roles of NEIL1, both in directly promoting virus replication and in evading innate immunity in IAV infection.

Assessment of genome complementarity in three beef-on-dairy crossbreds reveals sire-specific effects on production traits with comparable rates of genomic inbreeding reduction

BACKGROUND

Crossbreeding beef bulls with dairy cows can improve the economic value and fitness of calves not entering dairy production owing to increased meat yield and heterosis. However, outcrossing might reduce the dosage of alleles that confer local adaptation or result in a higher risk of dystocia due to increased calf size. Given the clear phenotypic differences between beef breeds, the varying phylogenetic distances between beef and dairy breeds, and the genomic variations within breeds, the attainable economic and fitness gains of calves will strongly depend on the selection of sires for crossing. Thus, the aim of this study was to assess genome complementarity between Angus (AAN), Limousin (LIM), or Simmental (SIM) beef bulls and Brown Swiss (BSW) dairy cows by quantifying genomic inbreeding reduction in F1 crosses and identifying genes potentially under BSW-specific selection that might be affected by outcrossing.

RESULTS

Low-pass sequencing data from 181 cows, 34 bulls, and 301 of their F1 progeny, and body weight and carcass composition measurements of 248 F1s were obtained. The high genomic inbreeding levels detected in the BSW cows were substantially reduced in the crossbreds, with only minor differences between the sire breeds. In the BSW cows, 585 candidate genes under selection were identified, overrepresenting genes associated with milk, meat and carcass, and production traits. Only a few genes were strongly differentiated at nonsynonymous variants between the BSW and beef breeds, including four tightly clustered genes (FAM184B, NCAPG, DCAF16, and LCORL) nearly fixed for alternate alleles in the BSW cows but mostly heterozygous or homozygous for the reference alleles in the AAN and LIM bulls. The alternate allele dosage at these genes significantly correlated with reduced carcass weight and protein mass in F1s.

CONCLUSION

Some of the few genes that were highly divergent between the BSW and beef breeds at nonsynonymous variants were likely under strong selection for reduced carcass weight in the BSW breed, potentially due to trade-offs between beef and dairy productions. As alleles with opposing effects still segregate in beef cattle, marker-assisted selection of mating pairs may be used to modulate the desired phenotypes and simultaneously decrease genomic inbreeding.

8-Oxoguanine DNA Glycosylase1 conceals oxidized guanine in nucleoprotein-associated RNA of respiratory syncytial virus

Respiratory syncytial virus (RSV), along with other prominent respiratory RNA viruses such as influenza and SARS-CoV-2, significantly contributes to the global incidence of respiratory tract infections. These pathogens induce the production of reactive oxygen species (ROS), which play a crucial role in the onset and progression of respiratory diseases. However, the mechanisms by which viral RNA manages ROS-induced base oxidation remain poorly understood. Here, we reveal that 8-oxo-7,8-dihydroguanine (8-oxoGua) is not merely an incidental byproduct of ROS activity but serves as a strategic adaptation of RSV RNA to maintain genetic fidelity by hijacking the 8-oxoguanine DNA glycosylase 1 (OGG1). Through RNA immunoprecipitation and next-generation sequencing, we discovered that OGG1 binding sites are predominantly found in the RSV antigenome, especially within guanine-rich sequences. Further investigation revealed that viral ribonucleoprotein complexes specifically exploit OGG1. Importantly, inhibiting OGG1's ability to recognize 8-oxoGua significantly decreases RSV progeny production. Our results underscore the viral replication machinery's adaptation to oxidative challenges, suggesting that inhibiting OGG1's reading function could be a novel strategy for antiviral intervention.

Suppression of the DNA repair enzyme NEIL2 promotes persistent inflammation and genomic damage in subjects with stable COPD and during severe exacerbations

Background

Chronic obstructive pulmonary disease (COPD) is a chronic inflammatory airway disease that is an independent risk factor for lung cancer. NEIL2, a DNA glycolase involved in DNA repair during transcription, has also been associated with an increased incidence of malignancies in humans. NEIL2 knockout mouse models have demonstrated increased inflammation and oxidative DNA damage in the lungs after exposure to an inflammatory insult, but data are lacking regarding NEIL2 function in individuals with stable COPD and during severe acute exacerbations of COPD (AECOPD). We investigated whether NEIL2 levels and oxidative DNA damage to the transcribed genome are altered in individuals with stable COPD and AECOPD.

Methods

The study was conducted at a single center in the US. Eligible subjects underwent a one-time 30 cc venous blood draw. The population consisted of 50 adults: 16 with stable COPD, 11 hospitalized for AECOPD, and 23 volunteers. We analyzed blood leukocytes for NEIL2 mRNA and DNA damage by RT-qPCR and LA-qPCR, respectively, in all groups. Plasma levels of seven biomarkers, CXCL1, CXCL8, CXCL9, CXCL10, CCL2, CCL11 and IL-6, were analyzed in the COPD groups using a magnetic bead panel (Millipore®).

Results

The NEIL2 mRNA levels were lower in individuals with stable COPD and AECOPD than in controls (0.72 for COPD, p = 0.0289; 0.407 for AECOPD, p = 0.0002). The difference in NEIL2 mRNA expression between the stable COPD group and AECOPD group was also statistically significant (p < 0.001). The fold change in DNA lesions per 10 kb of DNA was greater in the stable COPD (9.38, p < 0.0008) and AECOPD (15.81, p < 0.0004) groups than in the control group. The difference in fold change was also greater in the AECOPD group versus stable COPD p < 0.0236). Biomarker levels were not significantly different between the COPD groups. NEIL2 levels were correlated with plasma eosinophil levels in the stable COPD group (r = 0.737, p < 0.0027).

Conclusions

NEIL2 mRNA levels are significantly reduced in COPD subjects and are associated with increased DNA damage and inflammation. These results reveal a mechanism that promotes persistent airway inflammation and oxidative genomic damage and increases the risk of malignancy in this population.

For better or worse: crosstalk of parvovirus and host DNA damage response

Parvoviruses are a group of non-enveloped DNA viruses that have a broad spectrum of natural infections, making them important in public health. NS1 is the largest and most complex non-structural protein in the parvovirus genome, which is indispensable in the life cycle of parvovirus and is closely related to viral replication, induction of host cell apoptosis, cycle arrest, DNA damage response (DDR), and other processes. Parvovirus activates and utilizes the DDR pathway to promote viral replication through NS1, thereby increasing pathogenicity to the host cells. Here, we review the latest progress of parvovirus in regulating host cell DDR during the parvovirus lifecycle and discuss the potential of cellular consequences of regulating the DDR pathway, targeting to provide the theoretical basis for further elucidation of the pathogenesis of parvovirus and development of new antiviral drugs.

The DNA glycosylase NEIL2 is protective during SARS-CoV-2 infection

SARS-CoV-2 infection-induced aggravation of host innate immune response not only causes tissue damage and multiorgan failure in COVID-19 patients but also induces host genome damage and activates DNA damage response pathways. To test whether the compromised DNA repair capacity of individuals modulates the severity of COVID-19 infection, we analyze DNA repair gene expression in publicly available patient datasets and observe a lower level of the DNA glycosylase NEIL2 in the lungs of severely infected COVID-19 patients. This observation of lower NEIL2 levels is further validated in infected patients, hamsters and ACE2 receptor-expressing human A549 (A549-ACE2) cells. Furthermore, delivery of recombinant NEIL2 in A549-ACE2 cells shows decreased expression of proinflammatory genes and viral E-gene, as well as lowers the yield of viral progeny compared to mock-treated cells. Mechanistically, NEIL2 cooperatively binds to the 5'-UTR of SARS-CoV-2 genomic RNA to block viral protein synthesis. Collectively, these data strongly suggest that the maintenance of basal NEIL2 levels is critical for the protective response of hosts to viral infection and disease.