E-cigarettes increase the risk of adenoma formation in murine colorectal cancer model.

E-cigarettes (E.cigs) cause inflammation and damage to human organs, including the lungs and heart. In the gut, E.

F2,6BP restores mitochondrial genome integrity in Huntington's Disease.

Several reports have indicated that impaired mitochondrial function contributes to the development and progression of Huntington's disease (HD). Mitochondrial genome damage, particularly DNA strand breaks (SBs), is a potential cause for its compromised functionality. We have recently demonstrated that the activity of polynucleotide kinase 3'-phosphatase (PNKP), a critical DNA end-processing enzyme, is significantly reduced in the nuclear extract of HD patients due to lower level of a metabolite fructose-2,6 bisphosphate (F2,6BP), a biosynthetic product of 6-phosphofructo-2-kinase fructose-2,6-bisphosphatase 3 (PFKFB3), leading to persistent DNA SBs with 3'-phosphate termini, refractory to subsequent steps for repair completion.

Fructose-2,6-bisphosphate restores DNA repair activity of PNKP and ameliorates neurodegenerative symptoms in Huntington's disease.

Huntington's disease (HD) and spinocerebellar ataxia type 3 (SCA3) are the two most prevalent polyglutamine (polyQ) neurodegenerative diseases, caused by CAG (encoding glutamine) repeat expansion in the coding region of the huntingtin (HTT) and ataxin-3 (ATXN3) proteins, respectively. We have earlier reported that the activity, but not the protein level, of an essential DNA repair enzyme, polynucleotide kinase 3'-phosphatase (PNKP), is severely abrogated in both HD and SCA3 resulting in accumulation of double-strand breaks in patients' brain genome. While investigating the mechanistic basis for the loss of PNKP activity and accumulation of DNA double-strand breaks leading to neuronal death, we observed that PNKP interacts with the nuclear isoform of 6-phosphofructo-2-kinase fructose-2,6-bisphosphatase 3 (PFKFB3).

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).

E-cigarettes increase the risk of adenoma formation in murine colorectal cancer model.

Background: E-cigarettes (E.cigs) cause inflammation and damage to human organs, including the lungs and heart. In the gut, E.

Site-specific acetylation of polynucleotide kinase 3'-phosphatase regulates its distinct role in DNA repair pathways.

Mammalian polynucleotide kinase 3'-phosphatase (PNKP), a DNA end-processing enzyme with 3'-phosphatase and 5'-kinase activities, is involved in multiple DNA repair pathways, including base excision (BER), single-strand break (SSBR), and double-strand break repair (DSBR). However, little is known as to how PNKP functions in such diverse repair processes. Here we report that PNKP is acetylated at K142 (AcK142) by p300 constitutively but at K226 (AcK226) by CBP, only after DSB induction.

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.

Fructose-2,6-bisphosphate restores DNA repair activity of PNKP and ameliorates neurodegenerative symptoms in Huntington's disease.

Huntington's disease (HD) and spinocerebellar ataxia type 3 (SCA3) are the two most prevalent polyglutamine (polyQ) neurodegenerative diseases, caused by CAG (encoding glutamine) repeat expansion in the coding region of the huntingtin (HTT) and ataxin-3 (ATXN3) proteins, respectively. We have earlier reported that the activity, but not the protein level, of an essential DNA repair enzyme, polynucleotide kinase 3'-phosphatase (PNKP), is severely abrogated in both HD and SCA3 resulting in accumulation of double-strand breaks in patients' brain genome. While investigating the mechanistic basis for the loss of PNKP activity and accumulation of DNA double-strand breaks leading to neuronal death, we observed that PNKP interacts with the nuclear isoform of 6-phosphofructo-2-kinase fructose-2,6-bisphosphatase 3 (PFKFB3).

Site-specific acetylation of polynucleotide kinase 3'-phosphatase (PNKP) regulates its distinct role in DNA repair pathways.

Mammalian polynucleotide kinase 3'-phosphatase (PNKP) is a dual-function DNA end-processing enzyme with 3'-phosphatase and 5'-kinase activities, which generate 3'-OH and 5'-phosphate termini respectively, as substrates for DNA polymerase and DNA ligase to complete DNA repair. PNKP is thus involved in multiple DNA repair pathways, including base excision (BER), single-strand break (SSBR), and double-strand break repair (DSBR). However, little is known as to how PNKP functions in such diverse repair processes, which involve distinct sets of proteins.

Highly Sensitive Radioactivity-Based DNA 3'-Phosphatase Activity Assay for Polynucleotide Kinase 3'-Phosphatase.

Endogenous and exogenous genotoxic agents can generate various types of non-ligatable DNA ends at the site of strand break in the mammalian genome. If not repaired, such lesions will impede transcription and replication and can lead to various cellular pathologies. Among various "dirty" DNA ends, 3'-phosphate is one of the most abundant lesions generated in the mammalian cells.

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

As part of the antiviral response, cells activate the expressions of type I interferons (IFNs) and proinflammatory mediators to control viral spreading. Viral infections can impact DNA integrity; however, how DNA damage repair coordinates antiviral response remains elusive. Here we report Nei-like DNA glycosylase 2 (NEIL2), a transcription-coupled DNA repair protein, actively recognizes the oxidative DNA substrates induced by respiratory syncytial virus (RSV) infection to set the threshold of IFN-β expression.

Functional analysis of a conserved site mutation in the DNA end processing enzyme PNKP leading to ataxia with oculomotor apraxia type 4 in humans.

Polynucleotide kinase 3'-phosphatase (PNKP), an essential DNA end-processing enzyme in mammals with 3'-phosphatase and 5'-kinase activities, plays a pivotal role in multiple DNA repair pathways. Its functional deficiency has been etiologically linked to various neurological disorders. Recent reports have shown that mutation at a conserved glutamine (Gln) in PNKP leads to late-onset ataxia with oculomotor apraxia type 4 (AOA4) in humans and embryonic lethality in pigs.

Human DNA polymerase η promotes RNA-templated error-free repair of DNA double-strand breaks.

A growing body of evidence indicates that RNA plays a critical role in orchestrating DNA double-strand break repair (DSBR). Recently, we showed that homologous nascent RNA can be used as a template for error-free repair of double-strand breaks (DSBs) in the transcribed genome and to restore the missing sequence at the break site via the transcription-coupled classical nonhomologous end-joining (TC-NHEJ) pathway. TC-NHEJ is a complex multistep process in which a reverse transcriptase (RT) is essential for synthesizing the DNA strand from template RNA.

Regulation of DNA damage response by trimeric G-proteins.

Upon sensing DNA double-strand breaks (DSBs), eukaryotic cells either die or repair DSBs via one of the two competing pathways, i.e., non-homologous end-joining (NHEJ) or homologous recombination (HR).

NRF2 Regulates Cystathionine Gamma-Lyase Expression and Activity in Primary Airway Epithelial Cells Infected with Respiratory Syncytial Virus.

Cystathionine-y-lyase (CSE) is a critical enzyme for hydrogen sulfide (HS) biosynthesis and plays a key role in respiratory syncytial virus (RSV) pathogenesis. The transcription factor NRF2 is the master regulator of cytoprotective and antioxidant gene expression, and is degraded during RSV infection. While some evidence supports the role of NRF2 in CSE gene transcription, its role in CSE expression in airway epithelial cells is not known.

Protocols to Measure Oxidative Stress and DNA Damage in Asthma.

Asthma is associated with oxidative stress and oxidative damage of biomolecules, including DNA. Here, we describe the protocols to quantify reactive oxygen species (ROS) and oxidative stress markers in a mouse model of allergic airway inflammation. We also provide detailed methods to measure DNA damage by long-run real-time PCR for DNA-damage quantification (LORD-Q) assay and gene-specific DNA damage analyses by long amplicon (LA)-qPCR.

The DNA glycosylase NEIL2 plays a vital role in combating SARS-CoV-2 infection.

Compromised DNA repair capacity of individuals could play a critical role in the severity of SARS-CoV-2 infection-induced COVID-19. We therefore analyzed the expression of DNA repair genes in publicly available transcriptomic datasets of COVID-19 patients and found that the level of NEIL2, an oxidized base specific mammalian DNA glycosylase, is particularly low in the lungs of COVID-19 patients displaying severe symptoms. Downregulation of pulmonary NEIL2 in CoV-2-permissive animals and postmortem COVID-19 patients validated these results.

Innate Immune Responses to RSV Infection Facilitated by OGG1, an Enzyme Repairing Oxidatively Modified DNA Base Lesions.

The primary cause of morbidity and mortality from infection with respiratory syncytial virus (RSV) is the excessive innate immune response(s) (IIR) in which reactive oxygen species (ROS) play key role(s). However, the mechanisms for these processes are not fully understood. We hypothesized that expressions of IIR genes are controlled by the ROS-generated epigenetic-like mark 7,8-dihydro-8-oxo(d)guanine (8-oxo(d)Gua) and 8-oxoguanine DNA glycosylase1 (OGG1).

Transcription coupled base excision repair in mammalian cells: So little is known and so much to uncover.

Oxidized bases in the genome has been implicated in various human pathologies, including cancer, aging and neurological diseases. Their repair is initiated with excision by DNA glycosylases (DGs) in the base excision repair (BER) pathway. Among the five oxidized base-specific human DGs, OGG1 and NTH1 preferentially excise oxidized purines and pyrimidines, respectively, while NEILs remove both oxidized purines and pyrimidines.

Intrapulmonary administration of purified NEIL2 abrogates NF-κB-mediated inflammation.

Aberrant or constitutive activation of nuclear factor kappa B (NF-κB) contributes to various human inflammatory diseases and malignancies via the upregulation of genes involved in cell proliferation, survival, angiogenesis, inflammation, and metastasis. Thus, inhibition of NF-κB signaling has potential for therapeutic applications in cancer and inflammatory diseases. We reported previously that Nei-like DNA glycosylase 2 (NEIL2), a mammalian DNA glycosylase, is involved in the preferential repair of oxidized DNA bases from the transcriptionally active sequences via the transcription-coupled base excision repair pathway.

DNA glycosylase NEIL2 functions in multiple cellular processes.

Cell survival largely depends on the faithful maintenance of genetic material since genomic DNA is constantly exposed to genotoxicants from both endogenous and exogenous sources. The evolutionarily conserved base excision repair (BER) pathway is critical for maintaining genome integrity by eliminating highly abundant and potentially mutagenic oxidized DNA base lesions. BER is a multistep process, which is initiated with recognition and excision of the DNA base lesion by a DNA glycosylase, followed by DNA end processing, gap filling and finally sealing of the nick.

PIAS1 modulates striatal transcription, DNA damage repair, and SUMOylation with relevance to Huntington's disease.

DNA damage repair genes are modifiers of disease onset in Huntington's disease (HD), but how this process intersects with associated disease pathways remains unclear. Here we evaluated the mechanistic contributions of protein inhibitor of activated STAT-1 (PIAS1) in HD mice and HD patient-derived induced pluripotent stem cells (iPSCs) and find a link between PIAS1 and DNA damage repair pathways. We show that PIAS1 is a component of the transcription-coupled repair complex, that includes the DNA damage end processing enzyme polynucleotide kinase-phosphatase (PNKP), and that PIAS1 is a SUMO E3 ligase for PNKP.

The DNA Glycosylase NEIL2 Suppresses -Infection-Induced Inflammation and DNA Damage in Colonic Epithelial Cells.

Colorectal cancer (CRC) is the third most prevalent cancer, while the majority (80-85%) of CRCs are sporadic and are microsatellite stable (MSS), and approximately 15-20% of them display microsatellite instability (MSI). Infection and chronic inflammation are known to induce DNA damage in host tissues and can lead to oncogenic transformation of cells, but the role of DNA repair proteins in microbe-associated CRCs remains unknown. Using CRC-associated microbes such as () in a coculture with murine and human enteroid-derived monolayers (EDMs), here, we show that, among all the key DNA repair proteins, NEIL2, an oxidized base-specific DNA glycosylase, is significantly downregulated after infection.