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International Journal of Molecular... Sep 2023Multiple polyposes are heterogeneous diseases with different underlying molecular backgrounds, sharing a common symptom: the presence of transforming into cancerous...
Multiple polyposes are heterogeneous diseases with different underlying molecular backgrounds, sharing a common symptom: the presence of transforming into cancerous intestinal polyps. Recent reports have indicated biallelic mutations in the gene, which is involved in base excision repair (BER), as predisposing to an elevated risk of colorectal cancer (CRC). We aimed to evaluate the significance of the p.Q82* truncating variant in predisposition to intestinal polyposis by assessing its frequency in polyposis patients. We genotyped 644 Polish patients and 634 control DNA samples using high-resolution melting analysis (HRM) and Sanger sequencing. We found the p.Q82* variant in four polyposis patients; in three, it was homozygous (OR = 6.90, value = 0.202). Moreover, the p.R92C mutation was detected in one patient. We also looked more closely at the disease course in patients carrying mutations. Two homozygous patients also presented other neoplasia. In the family case, we noticed the earlier presence of polyps in the proband and early hepatoblastoma in his brother. We cannot univocally confirm the relationship of p.Q82* with an increased risk of CRC. However, homozygous p.Q82* was more frequent by 10-fold in patients without other mutations identified, which makes gene screening in this group reasonable.
Topics: Male; Humans; Adenomatous Polyposis Coli; Poland; Genetic Predisposition to Disease; Colorectal Neoplasms; Mutation; Deoxyribonuclease (Pyrimidine Dimer)
PubMed: 37834005
DOI: 10.3390/ijms241914548 -
Frontiers in Immunology 2023Chronic metabolic changes relevant to human immunodeficiency virus type 1 (HIV-1) infection and in response to antiretroviral therapy (ART) remain undetermined....
BACKGROUND
Chronic metabolic changes relevant to human immunodeficiency virus type 1 (HIV-1) infection and in response to antiretroviral therapy (ART) remain undetermined. Moreover, links between metabolic dysfunction caused by HIV and immunological inflammation in long-term treated individuals have been poorly studied.
METHODS
Untargeted metabolomics and inflammatory cytokine levels were assessed in 47 HIV-infected individuals including 22 immunological responders (IRs) and 25 non-responders (INRs) before and after ART. The IRs and INRs were matched by age, gender, baseline viral load, and baseline CD4+T cell counts. Another 25 age-matched uninfected healthy individuals were also included as controls.
RESULTS
Among the 770 plasma compounds detected in the current study, significant changes were identified in lipids, nucleotides, and biogenic amino acids between HIV-infected patients and healthy controls. Principal Component Analysis (PCA) and the Random Forest (RF) model suggested that levels of selected metabolites could differentiate HIV-infected patients clearly from healthy controls. However, the metabolite profiles identified in our patients were similar, and only three metabolites, maltotetraose, N, N-dimethyl-5-aminovalerate, and decadienedioic acid (C10:2-DC), were different between IRs and INRs following long-term ART. The pathway enrichment analysis results revealed that disturbances in pyrimidine metabolism, sphingolipid metabolism, and purine metabolism after HIV infection and these changes did not recover to normal levels in healthy controls even with suppressive ART. Correlation analysis of the metabolism-immune network indicated that interleukin (IL)-10, D-dimer, vascular cell adhesion molecule-1 (VCAM-1), intercellular cell adhesion molecule-1 (ICAM-1), and TNF-RII were positively correlated with most of the significantly changed lipid and amino acid metabolites but negatively correlated with metabolites in nucleotide metabolism.
CONCLUSIONS
Significant changes in many metabolites were observed in HIV-infected individuals before and after ART regardless of their immunological recovery status. The disturbed metabolic profiles of lipids and nucleotides in HIV infection did not recover to normal levels even after long-term ART. These changes are correlated with modified cytokines and biomarkers of chronic non-AIDS events, warranting tryout of interventions other than ART.
Topics: Humans; HIV Infections; HIV-1; CD4-Positive T-Lymphocytes; Lipids; Nucleotides
PubMed: 37828979
DOI: 10.3389/fimmu.2023.1254155 -
Molecular Cell Oct 2023UV irradiation induces "bulky" DNA photodimers such as (6-4)-photoproducts and cyclobutane pyrimidine dimers that are removed by nucleotide excision repair, a complex...
UV irradiation induces "bulky" DNA photodimers such as (6-4)-photoproducts and cyclobutane pyrimidine dimers that are removed by nucleotide excision repair, a complex process defective in the sunlight-sensitive and cancer-prone disease xeroderma pigmentosum. Some bacteria and lower eukaryotes can also repair photodimers by enzymatically simpler mechanisms, but such pathways have not been reported in normal human cells. Here, we have identified such a mechanism. We show that normal human cells can employ a DNA base excision repair process involving NTH1, APE1, PARP1, XRCC1, and FEN1 to rapidly remove a subset of photodimers at early times following UVC irradiation. Loss of these proteins slows the early rate of repair of photodimers in normal cells, ablates their residual repair in xeroderma pigmentosum cells, and increases UVC sensitivity ∼2-fold. These data reveal that human cells can excise photodimers using a long-patch base excision repair process that functions additively but independently of nucleotide excision repair.
Topics: Humans; Xeroderma Pigmentosum; DNA Repair; Pyrimidine Dimers; DNA Damage; DNA; Ultraviolet Rays; X-ray Repair Cross Complementing Protein 1
PubMed: 37816354
DOI: 10.1016/j.molcel.2023.09.013 -
Nucleic Acids Research Oct 2023UV radiation-induced DNA damages have adverse effects on genome integrity and cellular function. The most prevalent UV-induced DNA lesion is the cyclobutane pyrimidine...
UV radiation-induced DNA damages have adverse effects on genome integrity and cellular function. The most prevalent UV-induced DNA lesion is the cyclobutane pyrimidine dimer (CPD), which can cause skin disorders and cancers in humans. Rad4/XPC is a damage sensing protein that recognizes and repairs CPD lesions with high fidelity. However, the molecular mechanism of how Rad4/XPC interrogates CPD lesions remains elusive. Emerging viewpoints indicate that the association of Rad4/XPC with DNA, the insertion of a lesion-sensing β-hairpin of Rad4/XPC into the lesion site and the flipping of CPD's partner bases (5'-dA and 3'-dA) are essential for damage recognition. Characterizing these slow events is challenging due to their infrequent occurrence on molecular time scales. Herein, we have used enhanced sampling and molecular dynamics simulations to investigate the mechanism and energetics of lesion recognition by Rad4/XPC, considering multiple plausible pathways between the crystal structure of the Rad4-DNA complex and nine intermediate states. Our results shed light on the most likely sequence of events, their potential coupling and energetics. Upon association, Rad4 and DNA form an encounter complex in which CPD and its partner bases remain in the duplex and the BHD3 β-hairpin is yet to be inserted into the lesion site. Subsequently, sequential base flipping occurs, with the flipping of the 5'-dA base preceding that of the 3'-dA base, followed by the insertion of the BHD3 β-hairpin into the lesion site. The results presented here have significant implications for understanding the molecular basis of UV-related skin disorders and cancers and for paving the way for novel therapeutic strategies.
Topics: Humans; Pyrimidine Dimers; DNA Damage; DNA Repair; Saccharomyces cerevisiae Proteins; Protein Binding; DNA-Binding Proteins; DNA; Neoplasms; Ultraviolet Rays
PubMed: 37757853
DOI: 10.1093/nar/gkad730 -
Cureus Aug 2023Introduction Numerous studies have delved into the clinical efficacy of different topical treatments for actinic keratosis (AK). However, our understanding remains...
Exploring the Protective Efficacy of Topical Products for Actinic Keratosis Against Ultraviolet-Induced DNA and Protein Damage: An Experimental, Double-Blind Irradiation Study.
Introduction Numerous studies have delved into the clinical efficacy of different topical treatments for actinic keratosis (AK). However, our understanding remains limited regarding their capacity to prevent DNA and protein damage caused by ultraviolet radiation (UVR). Objectives The aim of this study was to analyze and compare the preventive capabilities of various AK-targeted products in countering DNA and protein alterations in human biopsies following exposure to experimental UVR. Methods Twelve healthy Caucasian volunteers (six men and six women) aged 18 years and above, with Fitzpatrick skin types II-III, participated in an experimental irradiation study. Six topical products, containing various ingredients (DNA repair enzymes, antioxidants, keratolytic agents, cyclooxygenase inhibitors, and/or sunscreens) were tested. The experimental sites were exposed to UVR at six times the minimal erythema dose for eight consecutive days. Each test product was applied 30 to 45 minutes before irradiation at a standard thickness of 2 mg/cm. A control site was treated with the vehicle alone, serving as a negative control. The study focused on cyclobutane pyrimidine dimers (CPDs) and protein carbonylation (PC) as molecular markers of UVR-induced DNA and protein damage, respectively. Results The efficacy of different AK-targeted topical products showed substantial variation when applied to normal skin before experimental exposure to UVR. While sunscreens, predictably, played a crucial role, additional ingredients (i.e., DNA repair enzymes and antioxidants) also acted as vital protective agents for both the cellular genome and proteome, shielding them against UVR-induced damage. Conclusion In topical products specifically designed for AK, the strategic integration of DNA repair enzymes and antioxidants, in addition to sunscreens, establishes a critical defense mechanism against the detrimental effects of UVR on cellular DNA and proteins.
PubMed: 37746407
DOI: 10.7759/cureus.44065 -
Environmental and Molecular Mutagenesis Apr 2024DNA damage occurs throughout life from a variety of sources, and it is imperative to repair damage in a timely manner to maintain genome stability. Thus, DNA repair... (Review)
Review
DNA damage occurs throughout life from a variety of sources, and it is imperative to repair damage in a timely manner to maintain genome stability. Thus, DNA repair mechanisms are a fundamental part of life. Nucleotide excision repair (NER) plays an important role in the removal of bulky DNA adducts, such as cyclobutane pyrimidine dimers from ultraviolet light or DNA crosslinking damage from platinum-based chemotherapeutics, such as cisplatin. A main component for the NER pathway is transcription factor IIH (TFIIH), a multifunctional, 10-subunit protein complex with crucial roles in both transcription and NER. In transcription, TFIIH is a component of the pre-initiation complex and is important for promoter opening and the phosphorylation of RNA Polymerase II (RNA Pol II). During repair, TFIIH is important for DNA unwinding, recruitment of downstream repair factors, and verification of the bulky lesion. Several different disease states can arise from mutations within subunits of the TFIIH complex. Most strikingly are xeroderma pigmentosum (XP), XP combined with Cockayne syndrome (CS), and trichothiodystrophy (TTD). Here, we summarize the recruitment and functions of TFIIH in the two NER subpathways, global genomic (GG-NER) and transcription-coupled NER (TC-NER). We will also discuss how TFIIH's roles in the two subpathways lead to different genetic disorders.
Topics: Humans; DNA; DNA Damage; DNA Repair; Excision Repair; Transcription Factor TFIIH; Transcription, Genetic; Xeroderma Pigmentosum
PubMed: 37545038
DOI: 10.1002/em.22568 -
Molecules (Basel, Switzerland) Jul 2023Diosmin is used to relieve chronic venous disease (CVD) symptoms. This study aimed to investigate the anti-inflammatory and antioxidant effects of...
Diosmin is used to relieve chronic venous disease (CVD) symptoms. This study aimed to investigate the anti-inflammatory and antioxidant effects of diosmetin-3--β-d-glucuronide, the major metabolite of diosmin, using human skin explants. The explants were exposed to substance P (inflammation model) or UVB irradiation (oxidative model) and to five diosmetin-3--β-d-glucuronide concentrations. Inflammation was evaluated through interleukin-8 (IL-8) secretion measurements and capillary dilation observation, and oxidation was evaluated by measuring the hydrogen peroxide levels and observing cyclobutane pyrimidine dimers (CPDs). In substance-P-exposed explants, diosmetin-3--β-d-glucuronide induced a significant decrease in IL-8 secretions, with a maximal effect at 2700 pg/mL (-49.6%), and it reduced the proportion of dilated capillaries and the mean luminal cross-sectional area ( < 0.0001 at all tested concentrations), indicating a vasoconstrictive effect. In UVB-irradiated fragments, diosmetin-3--β-d-glucuronide induced a significant decrease in hydrogen peroxide production and in the number of CPD-positive cells, reaching a maximal effect at the concentration of 2700 pg/mL (-48.6% and -52.0%, respectively). Diosmetin-3--β-d-glucuronide induced anti-inflammatory and antioxidant responses, with the maximal effect being reached at 2700 pg/mL and corresponding to the peak plasma concentration estimated after the oral intake of 600 mg of diosmin, the daily dose usually recommended for the treatment of CVD. These ex vivo findings suggest a protective role of diosmetin-3--β-d-glucuronide against inflammatory and oxidative stress affecting the vascular system in CVD pathophysiology.
Topics: Humans; Antioxidants; Glucuronides; Diosmin; Hydrogen Peroxide; Interleukin-8; Anti-Inflammatory Agents; Inflammation; Cardiovascular Diseases
PubMed: 37513462
DOI: 10.3390/molecules28145591 -
Metabolites Jun 2023The hormonal form of vitamin D, 1,25(OH)D, reduces UV-induced DNA damage. UV exposure initiates pre-vitamin D production in the skin, and continued UV exposure...
The hormonal form of vitamin D, 1,25(OH)D, reduces UV-induced DNA damage. UV exposure initiates pre-vitamin D production in the skin, and continued UV exposure photoisomerizes pre-vitamin D to produce "over-irradiation products" such as lumisterol (L). Cytochrome P450 side-chain cleavage enzyme (CYP11A1) in skin catalyzes the conversion of L to produce three main derivatives: 24-hydroxy-L [24(OH)L], 22-hydroxy-L [22(OH)L], and 20,22-dihydroxy-L [20,22(OH)L]. The current study investigated the photoprotective properties of the major over-irradiation metabolite, 24(OH)L, in human primary keratinocytes and human skin explants. The results indicated that treatment immediately after UV with either 24(OH)L or 1,25(OH)D reduced UV-induced cyclobutane pyrimidine dimers and oxidative DNA damage, with similar concentration response curves in keratinocytes, although in skin explants, 1,25(OH)D was more potent. The reductions in DNA damage by both compounds were, at least in part, the result of increased DNA repair through increased energy availability via increased glycolysis, as well as increased DNA damage recognition proteins in the nucleotide excision repair pathway. Reductions in UV-induced DNA photolesions by either compound occurred in the presence of lower reactive oxygen species. The results indicated that under in vitro and ex vivo conditions, 24(OH)L provided photoprotection against UV damage similar to that of 1,25(OH)D.
PubMed: 37512482
DOI: 10.3390/metabo13070775 -
JACS Au Jul 2023The direct and sequence-dependent investigation of photochemical processes in DNA on the way to cyclobutane pyrimidine dimers (CPDs) as DNA damage requires the probing...
The direct and sequence-dependent investigation of photochemical processes in DNA on the way to cyclobutane pyrimidine dimers (CPDs) as DNA damage requires the probing by photochemically different photosensitizers. The C-nucleosides of xanthone, thioxanthone, 3-methoxyxanthone, and triphenylene as photosensitizers were synthesized by Heck couplings and incorporated into ternary photoactive DNA architectures. This structural approach allows the site-selective excitation of the DNA by UV light. Together with a single defined site for T-T dimerization, not only the direct CPD formation but also the distance-dependent CPD formation in DNA as well as the possibility for energy transport processes could be investigated. Direct CPD formation was observed with xanthone, 3-methoxyxanthone, and triphenylene as sensitizers but not with thioxanthone. Only xanthone was able to induce CPDs remotely by a triplet energy transfer over up to six intervening A-T base pairs. Taken together, more precise information on the sequence dependence of the DNA triplet photochemistry was obtained.
PubMed: 37502149
DOI: 10.1021/jacsau.3c00167