Alcohol and endogenous aldehydes damage chromosomes and mutate stem cells

Effect of exercise on cravings levels in individuals with drug dependency: A systematic review

OBJECTIVE

This systematic review aims to assess the feasibility, acceptability, and efficacy of exercise-based interventions in reducing craving levels among individuals with drug dependency.

METHODS

This study included randomized controlled trials that investigated the effects of exercise on craving levels in individuals with drug dependence. We searched for relevant literature in PubMed, Web of Science, EMbase, The Cochrane Library, CNKI, China Biomedicine, Wanfang, and VIP databases from their inception until July 2024. Two researchers independently reviewed the literature. The quality of the studies was assessed using the PEDro scale, and the GRADE profiler software was utilized to evaluate the strength of the evidence. A qualitative synthesis was performed to describe the findings.

RESULTS

We included 26 studies involving a total of 1381 participants, with 787 in the experimental group and 594 in the control group. These studies were mainly conducted in China, the United States, and the United Kingdom, and were published mostly after 2018. The participants had typically been dependent on drugs for more than 5 years. The review found that exercise interventions were feasible and well-accepted, and effectively reduced drug cravings. Among the 26 studies, 22 showed positive outcomes in reducing cravings. The type of exercise appears to be a crucial factor. Aerobic exercises were more effective than resistance exercises. Out of 18 studies that included aerobic exercises, 17 reported significant reductions in cravings. In contrast, among the 4 studies that included resistance exercises, 3 did not find a significant impact on cravings.

CONCLUSION

Exercise is highly feasible and acceptable, significantly contributing to the reduction of drug cravings among individuals with drug dependency. The specific type of exercise appears to be a key determinant of the intervention's effectiveness. Aerobic exercises were more effective than resistance exercises. The evidence supporting these findings is of high quality, with an average score of 6.92 on the PEDro scale.

OTHERS

The research was supported by the Shanghai Key Laboratory of Human Performance, with the project number 11DZ2261100. Registration details can be found on PROSPEO under the number CRD42024525700 at www.crd.york.ac.uk.

Lysine β-hydroxybutyrylation promotes lipid accumulation in alcoholic liver disease

Continuous (chronic or sub-chronic) alcohol consumption induces a metabolic byproduct known as ketone bodies, and the accumulation of ketones leads to a life-threatening syndrome called alcoholic ketoacidosis. However, the mechanism underlining the physiological effects of ketone accumulation in alcoholic liver disease (ALD) is still in its infancy. Here, we discovered that mitochondrial acetyl-CoA accumulation was diverted into the ketogenesis pathway in ethanol-fed mice and ethanol-exposed hepatocytes. Unexpectedly, global protein lysine β-hydroxybutyrylation (Kbhb) was induced in response to increased ketogenesis-derived β-hydroxybutyrate (BHB) levels both in hepatocytes and in livers of mice. Focusing on the solute carrier family (SLCs), we found that SLC25A5 presented obvious Kbhb at lysine residues 147 and 166. Kbhb modifications at these two lysine residues stabilized SLC25A5 expression by blocking ubiquitin-proteasome pathway. Subsequent mutation analysis revealed that Kbhb of SLC25A5 at K147 and K166 had site-specific regulatory roles by increasing peroxisome proliferator activated receptor gamma (PPARγ) expression, which further promoting lipogenesis. Additionally, 3-hydroxy-3-methylglutaryl-coenzyme A synthase 2 (HMGCS2), a rate-limiting enzyme for BHB production, was profoundly induced by ethanol exposure, and knockout of Hmgcs2 with CRISPR/Cas9 attenuated SLC25A5 Kbhb. Together, our study demonstrated a widespread Kbhb landscape under ethanol exposure and clarified a physiological effect of Kbhb modification on liver lipid accumulation.

Reproductive and germ-cell mutagenic effects of poly-and perfluoroalkyl substances (PFAS) to Caenorhabditis elegans after multigenerational exposure

Per- and polyfluoroalkyl substances (PFAS) are a class of globally ubiquitous persistent organic pollutants (POPs). The developmental and reproductive toxicity of PFAS have attracted considerable attention. However, the influence of PFAS exposure on genomic stability of germ cells remains unexplored. In this study, we evaluated long-term reproductive toxicity of environmentally relevant levels of four long-chain PFAS compounds: perfluorooctanoic acid (PFOA, C8), perfluorononanoic acid (PFNA, C9), perfluorodecanoic acid (PFDA, C10), and perfluorooctanesulfonic acid (PFOS, C8), and examined their germ-cell mutagenicity in Caenorhabditis elegans. Our findings reveal that multigenerational exposure to PFAS exhibited minor impacts on development and reproduction of worms. Among all tested PFAS, PFNA significantly increased mutation frequencies of progeny by preferentially inducing T:A → C:G substitutions and small indels within repetitive regions. Further analysis of mutation spectra uncovered elevated frequencies of microhomology-mediated deletions and large deletions in PFOA-treated worms, indicating its potential activity in eliciting DNA double-strand breaks. This study provides the first comparative analysis of the genome-wide mutational profile of PFAS compounds, underscoring the importance of assessing germ-cell mutagenic actions of long-chain PFAS.

Drinking in despair: Unintended consequences of automation in China

The side effects of technological progress on the economy have been discussed frequently, but little is known regarding its health consequences. By combining the national individual-level panel data of alcohol drinking with the prefecture-level robot exposure rate in China, we find that one more robot exposure rate could induce up to 2.2% points increase in the probability of problem drinking. Such a pattern of problem drinking is explained by negative emotions, which can be ascribed to job loss due to substitution, higher income vulnerability, and reduced organization participation. Further, we provide evidence that automation can incur health costs, particularly for easily substituted workers, which would exacerbate health inequality in China. This paper sheds light on the impact of automation and the social incentives of problem drinking, emphasizing the possibly heterogeneous health cost accompanied by the automation process.

Genomic alterations in two patients with esophageal carcinosarcoma identified by whole genome sequencing: a case report

BACKGROUND

Esophageal carcinosarcoma (ECS) is a relatively rare malignancy, accounting for < 1% of all esophageal cancers. Its etiopathogenesis remains unknown. This study analyzed the genomic abnormalities in sarcomatous tumors from two patients undergoing subtotal esophagectomy using whole genome sequencing to elucidate the key characteristics of ECS.

CASE PRESENTATION

We identified TP53 driver mutations, copy number gains in 11q13 (including CCND1), and Apolipoprotein B mRNA editing enzyme catalytic polypeptide (APOBEC) signature enrichment in both ECS patients. Along with common genetic abnormalities, we identified CDKN2A driver mutations in case 1 and RAC1, NOTCH1, and TTC28 as novel fusion gene partners of MECOM in case 2. Notably, we detected germline pathogenic variant in Fanconi anemia (FA) complementation group I (FANCI) and group G (FANCG), which are involved in repairing DNA double-strand breaks by homologous recombination, for the first time, in ECS blood samples. These germline variants were truncating-type, Lys1221fs of FANCI (rs1567179036) for case 1 and Gln365Ter of FANCG (rs121434426) for case 2. We also identified somatic changes in cancer-associated pathways, such as PI3K/Akt/mTOR, cell cycle, and NOTCH signaling pathways, and structural chromosomal defects such as chromosome doubling.

CONCLUSIONS

Our findings indicate that therapeutic drugs targeting the activation signal or FA pathway might be effective in treating ECS, however, their therapeutic significance should be elucidated in future studies.

FANCD2-FANCI surveys DNA and recognizes double- to single-stranded junctions

DNA crosslinks block DNA replication and are repaired by the Fanconi anaemia pathway. The FANCD2-FANCI (D2-I) protein complex is central to this process as it initiates repair by coordinating DNA incisions around the lesion1. However, D2-I is also known to have a more general role in DNA repair and in protecting stalled replication forks from unscheduled degradation2-4. At present, it is unclear how DNA crosslinks are recognized and how D2-I functions in replication fork protection. Here, using single-molecule imaging, we show that D2-I is a sliding clamp that binds to and diffuses on double-stranded DNA. Notably, sliding D2-I stalls on encountering single-stranded-double-stranded (ss-ds) DNA junctions, structures that are generated when replication forks stall at DNA lesions5. Using cryogenic electron microscopy, we determined structures of D2-I on DNA that show that stalled D2-I makes specific interactions with the ss-dsDNA junction that are distinct from those made by sliding D2-I. Thus, D2-I surveys dsDNA and, when it reaches an ssDNA gap, it specifically clamps onto ss-dsDNA junctions. Because ss-dsDNA junctions are found at stalled replication forks, D2-I can identify sites of DNA damage. Therefore, our data provide a unified molecular mechanism that reconciles the roles of D2-I in the recognition and protection of stalled replication forks in several DNA repair pathways.

ALDH1A3-acetaldehyde metabolism potentiates transcriptional heterogeneity in melanoma

Cancer cellular heterogeneity and therapy resistance arise substantially from metabolic and transcriptional adaptations, but how these are interconnected is poorly understood. Here, we show that, in melanoma, the cancer stem cell marker aldehyde dehydrogenase 1A3 (ALDH1A3) forms an enzymatic partnership with acetyl-coenzyme A (CoA) synthetase 2 (ACSS2) in the nucleus to couple high glucose metabolic flux with acetyl-histone H3 modification of neural crest (NC) lineage and glucose metabolism genes. Importantly, we show that acetaldehyde is a metabolite source for acetyl-histone H3 modification in an ALDH1A3-dependent manner, providing a physiologic function for this highly volatile and toxic metabolite. In a zebrafish melanoma residual disease model, an ALDH1-high subpopulation emerges following BRAF inhibitor treatment, and targeting these with an ALDH1 suicide inhibitor, nifuroxazide, delays or prevents BRAF inhibitor drug-resistant relapse. Our work reveals that the ALDH1A3-ACSS2 couple directly coordinates nuclear acetaldehyde-acetyl-CoA metabolism with specific chromatin-based gene regulation and represents a potential therapeutic vulnerability in melanoma.

G-quadruplexes are a source of vulnerability in BRCA2 deficient granule cell progenitors and medulloblastoma

Biallelic pathogenic variants in the essential DNA repair gene BRCA2 causes Fanconi anemia, complementation group FA-D1. Patients in this group are highly prone to develop embryonal tumors, most commonly medulloblastoma arising from the cerebellar granule cell progenitors (GCPs). GCPs undergo high proliferation in the postnatal cerebellum under SHH activation, but the type of DNA lesions that require the function of the BRCA2 to prevent tumorigenesis remains unknown. To identify such lesions, we assessed both GCP neurodevelopment and tumor formation using a mouse model with deletion of exons three and four of Brca2 in the central nervous system, coupled with global Trp53 loss. Brca2 Δex3-4 ;Trp53 -/- animals developed SHH subgroup medulloblastomas with complete penetrance. Whole-genome sequencing of the tumors identified structural variants with breakpoints enriched in areas overlapping G-quadruplexes (G4s). Brca2-deficient GCPs exhibited decreased replication speed in the presence of the G4-stabilizer pyridostatin. Pif1 helicase, which resolves G4s during replication, was highly upregulated in tumors, and Pif1 knockout in primary MB tumor cells resulted in increased genome instability upon pyridostatin treatment. These data suggest that G4s may represent sites prone to replication stalling in highly proliferative GCPs and without BRCA2, G4s become a source of genome instability. Tumor cells upregulate G4-resolving helicases to facilitate rapid proliferation through G4s highlighting PIF1 helicase as a potential therapeutic target for treatment of BRCA2-deficient medulloblastomas.

Dual role of proliferating cell nuclear antigen monoubiquitination in facilitating Fanconi anemia-mediated interstrand crosslink repair

The Fanconi anemia (FA) repair pathway governs repair of highly genotoxic DNA interstrand crosslinks (ICLs) and relies on translesion synthesis (TLS). TLS is facilitated by REV1 or site-specific monoubiquitination of proliferating cell nuclear antigen (PCNA) (PCNA-Ub) at lysine 164 (K164). A PcnaK164R/K164R but not Rev1-/- mutation renders mammals hypersensitive to ICLs. Besides the FA pathway, alternative pathways have been associated with ICL repair (1, 2), though the decision making between those remains elusive. To study the dependence and relevance of PCNA-Ub in FA repair, we intercrossed PcnaK164R/+; Fancg-/+ mice. A combined mutation (PcnaK164R/K164R; Fancg-/- ) was found embryonically lethal. RNA-seq of primary double-mutant (DM) mouse embryonic fibroblasts (MEFs) revealed elevated levels of replication stress-induced checkpoints. To exclude stress-induced confounders, we utilized a Trp53 knock-down to obtain a model to study ICL repair in depth. Regarding ICL-induced cell toxicity, cell cycle arrest, and replication fork progression, single-mutant and DM MEFs were found equally sensitive, establishing PCNA-Ub to be critical for FA-ICL repair. Immunoprecipitation and spectrometry-based analysis revealed an unknown role of PCNA-Ub in excluding mismatch recognition complex MSH2/MSH6 from being recruited to ICLs. In conclusion, our results uncovered a dual function of PCNA-Ub in ICL repair, i.e. exclude MSH2/MSH6 recruitment to channel the ICL toward canonical FA repair, in addition to its established role in coordinating TLS opposite the unhooked ICL.

ALDH2 mutations and defense against genotoxic aldehydes in cancer and inherited bone marrow failure syndromes

Reactive aldehydes, for instance, formaldehyde and acetaldehyde, are important endogenous or environmental mutagens by virtue of their abilities to produce a DNA lesion called interstrand crosslink (ICL). Aldehyde-metabolizing enzymes such as aldehyde dehydrogenases (ALDHs) and the Fanconi anemia (FA) pathway constitute the main defense lines against aldehyde-induced genotoxicity. Biallelic mutations of genes in any one of the FA complementation groups can impair the ICL repair mechanism and cause FA, a heterogeneous disorder manifested by bone marrow failure (BMF), congenital abnormality and a strong predisposition to cancer. The defective ALDH2 polymorphism rs671 (ALDH2*2) is a known risk and prognostic factor for alcohol drinking-associated cancers. Recent studies suggest that it also promotes BMF and cancer development in FA, and its combination with alcohol dehydrogenase 5 (ADH5) mutations causes aldehyde degradation deficiency syndrome (ADDS), also known by its symptoms as aplastic anemia, mental retardation, and dwarfism syndrome. ALDH2*2 and another pathogenic variant in the alcohol-metabolizing pathway, ADH1B1*1, is prevalent among East Asians. Also, other ALDH2 genotypes with disease-modifying potentials have lately been identified in different populations. Therefore, it would be appropriate to summarize current knowledge of genotoxic aldehydes and defense mechanisms against them to shed new light on the pathogenic effects of ALDH2 variants together with other genetic and environmental modifiers on cancer and inherited BMF syndromes. Lastly, we also presented potential treatment strategies for FA, ADDS and cancer based on the manipulation of aldehyde-induced genotoxicity.

Modular development of organelle-targeting fluorescent probes for imaging formaldehyde in live cells

Formaldehyde (FA) is endogenously generated via fundamental biological processes in living systems. Aberrant FA homeostasis in subcellular microenvironments is implicated in numerous pathological conditions. Fluorescent probes for detecting FA in specific organelles are thus of great research interest. Herein, we present a modular strategy to construct diverse organelle-targeting FA probes by incorporating selective organelle-targeting moieties into the scaffold of a 1,8-naphthalimide-derived FA fluorescent probe. These probes react with FA through the 2-aza-Cope arrangement and exhibit highly selective fluorescence increases for detecting FA in aqueous solutions. Moreover, these organelle-targeting probes, i.e., FFP551-Nuc, FFP551-ER, FFP551-Mito, and FFP551-Lyso, allow selective localization and imaging of FA in the nucleus, endoplasmic reticulum, mitochondria, and lysosomes of live mammalian cells, respectively. Furthermore, FFP551-Nuc has been successfully employed to monitor changes of endogenous FA levels in the nucleus of live mammalian cells. Overall, these probes should represent new imaging tools for studying the biology and pathology associated with FA in different intracellular compartments.

Dual effects of endogenous formaldehyde on the organism and drugs for its removal

Endogenous formaldehyde (FA) is produced in the human body via various mechanisms to preserve healthy energy metabolism and safeguard the organism. However, endogenous FA can have several negative effects on the body through epigenetic alterations, including cancer growth promotion; neuronal, hippocampal and endothelial damages; atherosclerosis acceleration; haemopoietic stem cell destruction and haemopoietic cell production reduction. Certain medications with antioxidant effects, such as glutathione, vitamin E, resveratrol, alpha lipoic acid and polyphenols, lessen the detrimental effects of endogenous FA by reducing oxidative stress, directly scavenging endogenous FA or promoting its degradation. This study offers fresh perspectives for managing illnesses associated with endogenous FA exposure.

Identification of acetaldehyde based on plasmonic patterns of a gold nanostructure conjugated with chromophore and H2O2: a new platform for the rapid and low-cost analysis of carcinogenic agents by colorimetric affordable test strip (CATS)

Acetaldehyde, a prevalent carbonyl compound in fermented foods, poses challenges in various applications due to its reactivity. This study addresses the need for efficient acetaldehyde detection methods across biotechnological, environmental, pharmaceutical, and food sectors. Herein, we present a novel colorimetric/UV spectrophotometric approach utilizing gold nanoparticles (AuNPs), particularly gold nano-flowers (AuNFs), for sensitive acetaldehyde identification. The method exhibits a notable sensitivity, detecting acetaldehyde at concentrations as low as 0.1 μM. The mechanism involves the interaction of acetaldehyde molecules with AuNFs, leading to a significant change in the absorbance spectrum, which serves as the basis for detection. Moreover, its applicability extends to human biofluids, notably urine samples. Integration with a cost-effective one-drop microfluidic colorimetric device (OD-μPCD) enables the development of an affordable test strip (CATS). This semi-analytical device, employing a multichannel OD-μPCD, facilitates real-time analysis of acetaldehyde in human samples. Our findings demonstrate the pioneering utilization of AuNPs for selective and sensitive acetaldehyde detection, promising advancements in environmental and occupational safety standards, and laying a foundation for enhanced detection and monitoring of related volatile organic compounds (VOCs).

Primordial germ cell DNA demethylation and development require DNA translesion synthesis

Mutations in DNA damage response (DDR) factors are associated with human infertility, which affects up to 15% of the population. The DDR is required during germ cell development and meiosis. One pathway implicated in human fertility is DNA translesion synthesis (TLS), which allows replication impediments to be bypassed. We find that TLS is essential for pre-meiotic germ cell development in the embryo. Loss of the central TLS component, REV1, significantly inhibits the induction of human PGC-like cells (hPGCLCs). This is recapitulated in mice, where deficiencies in TLS initiation (Rev1-/- or PcnaK164R/K164R) or extension (Rev7 -/-) result in a > 150-fold reduction in the number of primordial germ cells (PGCs) and complete sterility. In contrast, the absence of TLS does not impact the growth, function, or homeostasis of somatic tissues. Surprisingly, we find a complete failure in both activation of the germ cell transcriptional program and in DNA demethylation, a critical step in germline epigenetic reprogramming. Our findings show that for normal fertility, DNA repair is required not only for meiotic recombination but for progression through the earliest stages of germ cell development in mammals.

Gut-liver axis: Recent concepts in pathophysiology in alcohol-associated liver disease

The growing recognition of the role of the gut microbiome's impact on alcohol-associated diseases, especially in alcohol-associated liver disease, emphasizes the need to understand molecular mechanisms involved in governing organ-organ communication to identify novel avenues to combat alcohol-associated diseases. The gut-liver axis refers to the bidirectional communication and interaction between the gut and the liver. Intestinal microbiota plays a pivotal role in maintaining homeostasis within the gut-liver axis, and this axis plays a significant role in alcohol-associated liver disease. The intricate communication between intestine and liver involves communication between multiple cellular components in each organ that enable them to carry out their physiological functions. In this review, we focus on novel approaches to understanding how chronic alcohol exposure impacts the microbiome and individual cells within the liver and intestine, as well as the impact of ethanol on the molecular machinery required for intraorgan and interorgan communication.

A glycolytic metabolite bypasses "two-hit" tumor suppression by BRCA2

Knudson's "two-hit" paradigm posits that carcinogenesis requires inactivation of both copies of an autosomal tumor suppressor gene. Here, we report that the glycolytic metabolite methylglyoxal (MGO) transiently bypasses Knudson's paradigm by inactivating the breast cancer suppressor protein BRCA2 to elicit a cancer-associated, mutational single-base substitution (SBS) signature in nonmalignant mammary cells or patient-derived organoids. Germline monoallelic BRCA2 mutations predispose to these changes. An analogous SBS signature, again without biallelic BRCA2 inactivation, accompanies MGO accumulation and DNA damage in Kras-driven, Brca2-mutant murine pancreatic cancers and human breast cancers. MGO triggers BRCA2 proteolysis, temporarily disabling BRCA2's tumor suppressive functions in DNA repair and replication, causing functional haploinsufficiency. Intermittent MGO exposure incites episodic SBS mutations without permanent BRCA2 inactivation. Thus, a metabolic mechanism wherein MGO-induced BRCA2 haploinsufficiency transiently bypasses Knudson's two-hit requirement could link glycolysis activation by oncogenes, metabolic disorders, or dietary challenges to mutational signatures implicated in cancer evolution.

Crosstalk between DNA Damage Repair and Metabolic Regulation in Hematopoietic Stem Cells

Self-renewal and differentiation are two characteristics of hematopoietic stem cells (HSCs). Under steady physiological conditions, most primitive HSCs remain quiescent in the bone marrow (BM). They respond to different stimuli to refresh the blood system. The transition from quiescence to activation is accompanied by major changes in metabolism, a fundamental cellular process in living organisms that produces or consumes energy. Cellular metabolism is now considered to be a key regulator of HSC maintenance. Interestingly, HSCs possess a distinct metabolic profile with a preference for glycolysis rather than oxidative phosphorylation (OXPHOS) for energy production. Byproducts from the cellular metabolism can also damage DNA. To counteract such insults, mammalian cells have evolved a complex and efficient DNA damage repair (DDR) system to eliminate various DNA lesions and guard genomic stability. Given the enormous regenerative potential coupled with the lifetime persistence of HSCs, tight control of HSC genome stability is essential. The intersection of DDR and the HSC metabolism has recently emerged as an area of intense research interest, unraveling the profound connections between genomic stability and cellular energetics. In this brief review, we delve into the interplay between DDR deficiency and the metabolic reprogramming of HSCs, shedding light on the dynamic relationship that governs the fate and functionality of these remarkable stem cells. Understanding the crosstalk between DDR and the cellular metabolism will open a new avenue of research designed to target these interacting pathways for improving HSC function and treating hematologic disorders.

Hematopoietic Stem Cells as an Integrative Hub Linking Lifestyle to Cardiovascular Health

Despite breakthroughs in modern medical care, the incidence of cardiovascular disease (CVD) is even more prevalent globally. Increasing epidemiologic evidence indicates that emerging cardiovascular risk factors arising from the modern lifestyle, including psychosocial stress, sleep problems, unhealthy diet patterns, physical inactivity/sedentary behavior, alcohol consumption, and tobacco smoking, contribute significantly to this worldwide epidemic, while its underpinning mechanisms are enigmatic. Hematological and immune systems were recently demonstrated to play integrative roles in linking lifestyle to cardiovascular health. In particular, alterations in hematopoietic stem cell (HSC) homeostasis, which is usually characterized by proliferation, expansion, mobilization, megakaryocyte/myeloid-biased differentiation, and/or the pro-inflammatory priming of HSCs, have been shown to be involved in the persistent overproduction of pro-inflammatory myeloid leukocytes and platelets, the cellular protagonists of cardiovascular inflammation and thrombosis, respectively. Furthermore, certain lifestyle factors, such as a healthy diet pattern and physical exercise, have been documented to exert cardiovascular protective effects through promoting quiescence, bone marrow retention, balanced differentiation, and/or the anti-inflammatory priming of HSCs. Here, we review the current understanding of and progression in research on the mechanistic interrelationships among lifestyle, HSC homeostasis, and cardiovascular health. Given that adhering to a healthy lifestyle has become a mainstream primary preventative approach to lowering the cardiovascular burden, unmasking the causal links between lifestyle and cardiovascular health from the perspective of hematopoiesis would open new opportunities to prevent and treat CVD in the present age.

Research Progress on the Correlation between Acetaldehyde Dehydrogenase 2 and Hepatocellular Carcinoma Development

Hepatocellular carcinoma (HCC) is the predominant pathologic type of primary liver cancer. It is a malignant tumor of liver epithelial cells. There are many ways to treat HCC, but the survival rate for HCC patients remains low. Therefore, understanding the underlying mechanisms by which HCC occurs and develops is critical to explore new therapeutic targets. Aldehyde dehydrogenase 2 (ALDH2) is an important player in the redox reaction of ethanol with endogenous aldehyde products released by lipid peroxidation. Increasing evidence suggests that ALDH2 is a crucial regulator of human tumor development, including HCC. Therefore, clarifying the relationship between ALDH2 and HCC is helpful for formulating rational treatment strategies. This review highlights the regulatory roles of ALDH2 in the development of HCC, elucidates the multiple potential mechanisms by which ALDH2 regulates the development of HCC, and summarizes the progress of research on ALDH2 gene polymorphisms and HCC susceptibility. Meanwhile, we envision viable strategies for targeting ALDH2 in the treatment of HCC SIGNIFICANCE STATEMENT: Numerous studies have aimed to explore novel therapeutic targets for HCC, and ALDH2 has been reported to be a critical regulator of HCC progression. This review discusses the functions, molecular mechanisms, and clinical significance of ALDH2 in the development of HCC and examines the prospects of ALDH2-based therapy for HCC.

Alcohol-associated liver cancer

Heavy alcohol intake induces a wide spectrum of liver diseases ranging from steatosis, steatohepatitis, cirrhosis, and HCC. Although alcohol consumption is a well-known risk factor for the development, morbidity, and mortality of HCC globally, alcohol-associated hepatocellular carcinoma (A-HCC) is poorly characterized compared to viral hepatitis-associated HCC. Most A-HCCs develop after alcohol-associated cirrhosis (AC), but the direct carcinogenesis from ethanol and its metabolites to A-HCC remains obscure. The differences between A-HCC and HCCs caused by other etiologies have not been well investigated in terms of clinical prognosis, genetic or epigenetic landscape, molecular mechanisms, and heterogeneity. Moreover, there is a huge gap between basic research and clinical practice due to the lack of preclinical models of A-HCC. In the current review, we discuss the pathogenesis, heterogeneity, preclinical approaches, epigenetic, and genetic profiles of A-HCC, and discuss the current insights into and the prospects for future research on A-HCC. The potential effect of alcohol on cholangiocarcinoma and liver metastasis is also discussed.

Microplastics dampen the self-renewal of hematopoietic stem cells by disrupting the gut microbiota-hypoxanthine-Wnt axis

Microplastics (MPs) are contaminants ubiquitously found in the global biosphere that enter the body through inhalation or ingestion, posing significant risks to human health. Recent studies emerge that MPs are present in the bone marrow and damage the hematopoietic system. However, it remains largely elusive about the specific mechanisms by which MPs affect hematopoietic stem cells (HSCs) and their clinical relevance in HSC transplantation (HSCT). Here, we established a long-term MPs intake mouse model and found that MPs caused severe damage to the hematopoietic system. Oral gavage administration of MPs or fecal transplantation of microbiota from MPs-treated mice markedly undermined the self-renewal and reconstitution capacities of HSCs. Mechanistically, MPs did not directly kill HSCs but disrupted gut structure and permeability, which eventually ameliorated the abundance of Rikenellaceae and hypoxanthine in the intestine and inactivated the HPRT-Wnt signaling in bone marrow HSCs. Furthermore, administration of Rikenellaceae or hypoxanthine in mice as well as treatment of WNT10A in the culture system substantially rescued the MPs-induced HSC defects. Finally, we validated in a cohort of human patients receiving allogenic HSCT from healthy donors, and revealed that the survival time of patients was negatively correlated with levels of MPs, while positively with the abundance of Rikenellaceae, and hypoxanthine in the HSC donors' feces and blood. Overall, our study unleashes the detrimental roles and mechanisms of MPs in HSCs, which provides potential strategies to prevent hematopoietic damage from MPs and serves as a fundamental critique for selecting suitable donors for HSCT in clinical practice.

p53 regulates diverse tissue-specific outcomes to endogenous DNA damage in mice

DNA repair deficiency can lead to segmental phenotypes in humans and mice, in which certain tissues lose homeostasis while others remain seemingly unaffected. This may be due to different tissues facing varying levels of damage or having different reliance on specific DNA repair pathways. However, we find that the cellular response to DNA damage determines different tissue-specific outcomes. Here, we use a mouse model of the human XPF-ERCC1 progeroid syndrome (XFE) caused by loss of DNA repair. We find that p53, a central regulator of the cellular response to DNA damage, regulates tissue dysfunction in Ercc1-/- mice in different ways. We show that ablation of p53 rescues the loss of hematopoietic stem cells, and has no effect on kidney, germ cell or brain dysfunction, but exacerbates liver pathology and polyploidisation. Mechanistically, we find that p53 ablation led to the loss of cell-cycle regulation in the liver, with reduced p21 expression. Eventually, p16/Cdkn2a expression is induced, serving as a fail-safe brake to proliferation in the absence of the p53-p21 axis. Taken together, our data show that distinct and tissue-specific functions of p53, in response to DNA damage, play a crucial role in regulating tissue-specific phenotypes.

Predictors of congenital anomalies among neonates admitted to public hospitals in eastern Ethiopia: a case-control study

OBJECTIVE

Over 8 million newborns worldwide have congenital anomalies; 3.2 million have resultant disabilities. Ethiopia has a high burden of neonatal congenital anomalies, but research on predictors is limited. This study investigated predictors of neonatal congenital anomalies in eastern Ethiopia.

METHODS

A facility-based unmatched case-control study on 387 mother-infant pairs (129 cases, 258 controls) in public hospitals was conducted. Data were obtained using an interviewer-administered structured questionnaire and a medical record review. Binary logistic regression with adjusted odds ratios (AOR) and 95% confidence intervals (CI) was used to identify predictors of congenital anomaly.

RESULTS

Nervous system anomalies were most common 84 (65.1%), followed by gastrointestinal system anomalies 20 (15.5%). Maternal anemia (AOR: 4.37, 95% CI: 2.48-7.69), alcohol consumption during index pregnancy (AOR: 4.01, 95% CI: 1.88-8.54), khat chewing (AOR: 1.73; 95% CI: 1.04-2.85), rural residence (AOR: 1.73, 95% CI: 1.04-2.85) and antenatal care attendance (AOR: 0.43, 95% CI: 0.22-0.84) were significant predictors of congenital anomaly.

CONCLUSION

Several risk factors for congenital anomalies were identified. To reduce risk, antenatal care services should be improved and mothers encouraged to avoid harmful substances during pregnancy and maintain a healthy lifestyle. Intervention strategies are needed to target these risk factors.

Constitutional chromosomal anomalies in children, fetal alcohol syndrome, and maternal toxicant exposures: A longitudinal cohort study

DNA alterations in gametes, which may occur either spontaneously or as a result of exposure to genotoxicants, can lead to constitutional chromosomal anomalies in the offspring. Alcohol is an established genotoxicant. The goal of this hypothesis-testing longitudinal cohort study was to evaluate the effect of significant/sustained maternal alcohol exposure on clinically diagnosed constitutional chromosomal anomalies among children diagnosed with fetal alcohol syndrome (FAS). De-identified eligibility and claim healthcare records, prospectively generated from the 1990-2012 Florida Medicaid system within the Independent Healthcare Research Database (IHRD), were analyzed. Children examined were continuously eligible with ≥ 8 outpatient office visits during the 96-month period following birth. Among these children, 377 were diagnosed with FAS and 137,135 were not. The incidence rate of chromosomal anomalies involving segregation (trisomy 13, 18, or 21, n = 625), microdeletions (microdeletion syndromes, n = 39), and point mutations (sickle-cell anemia/cystic fibrosis, n = 2570) were examined using frequency risk ratio (RR) and logistic regression (adjusted odds ratio (aOR) for sex, race, residence, socioeconomic/environmental exposure status, and birth date) models. The incidence rates of chromosomal anomalies involving segregation (RR=5.92, aOR=5.85) and microdeletions (RR=41.6, aOR=34.1) were significantly increased in the FAS cohort as compared to the non-diagnosed cohort, but there was no difference in the incidence rate of point mutations (RR=1.14, aOR=1.29). Maternal toxicant exposure should be considered in the etiology of constitutional chromosomal anomaly in offspring.

Homologous recombination contributes to the repair of acetaldehyde-induced DNA damage

Acetaldehyde, a chemical that can cause DNA damage and contribute to cancer, is prevalently present in our environment, e.g. in alcohol, tobacco, and food. Although aldehyde potentially promotes crosslinking reactions among biological substances including DNA, RNA, and protein, it remains unclear what types of DNA damage are caused by acetaldehyde and how they are repaired. In this study, we explored mechanisms involved in the repair of acetaldehyde-induced DNA damage by examining the cellular sensitivity to acetaldehyde in the collection of human TK6 mutant deficient in each genome maintenance system. Among the mutants, mismatch repair mutants did not show hypersensitivity to acetaldehyde, while mutants deficient in base and nucleotide excision repair pathways or homologous recombination (HR) exhibited higher sensitivity to acetaldehyde than did wild-type cells. We found that acetaldehyde-induced RAD51 foci representing HR intermediates were prolonged in HR-deficient cells. These results indicate a pivotal role of HR in the repair of acetaldehyde-induced DNA damage. These results suggest that acetaldehyde causes complex DNA damages that require various types of repair pathways. Mutants deficient in the removal of protein adducts from DNA ends such as TDP1-/- and TDP2-/- cells exhibited hypersensitivity to acetaldehyde. Strikingly, the double mutant deficient in both TDP1 and RAD54 showed similar sensitivity to each single mutant. This epistatic relationship between TDP1-/- and RAD54-/- suggests that the protein-DNA adducts generated by acetaldehyde need to be removed for efficient repair by HR. Our study would help understand the molecular mechanism of the genotoxic and mutagenic effects of acetaldehyde.

Lung Cancer and Lifestyle Factors: Umbrella Review

This review explores the effect of common everyday factors, such as alcohol, tea and coffee consumption, on the risk for lung cancer. We performed an umbrella review of current systematic reviews. The risk for lung cancer was increased with alcohol or coffee intake and decreased with tea intake. While evidence for alcohol is of low quality, the effect of coffee may be confounded by the smoking effect. The protective effect of tea intake is present, but the evidence is also of low quality.

Multiple DNA repair pathways prevent acetaldehyde-induced mutagenesis in yeast

Acetaldehyde is the primary metabolite of alcohol and is present in many environmental sources including tobacco smoke. Acetaldehyde is genotoxic, whereby it can form DNA adducts and lead to mutagenesis. Individuals with defects in acetaldehyde clearance pathways have increased susceptibility to alcohol-associated cancers. Moreover, a mutation signature specific to acetaldehyde exposure is widespread in alcohol and smoking-associated cancers. However, the pathways that repair acetaldehyde-induced DNA damage and thus prevent mutagenesis are vaguely understood. Here, we used Saccharomyces cerevisiae to systematically delete genes in each of the major DNA repair pathways to identify those that alter acetaldehyde-induced mutagenesis. We found that deletion of the nucleotide excision repair (NER) genes, RAD1 or RAD14, led to an increase in mutagenesis upon acetaldehyde exposure. Acetaldehyde-induced mutations were dependent on translesion synthesis as well as DNA inter-strand crosslink (ICL) repair in Δrad1 strains. Moreover, whole genome sequencing of the mutated isolates demonstrated an increase in C→A changes coupled with an enrichment of gCn→A changes in the acetaldehyde-treated Δrad1 isolates. The gCn→A mutation signature has been shown to be diagnostic of acetaldehyde exposure in yeast and in human cancers. We also demonstrated that the deletion of the two DNA-protein crosslink (DPC) repair proteases, WSS1 and DDI1, also led to increased acetaldehyde-induced mutagenesis. Defects in base excision repair (BER) led to a mild increase in mutagenesis, while defects in mismatch repair (MMR), homologous recombination repair (HR) and post replicative repair pathways did not impact mutagenesis upon acetaldehyde exposure. Our results in yeast were further corroborated upon analysis of whole exome sequenced liver cancers, wherein, tumors with defects in ERCC1 and ERCC4 (NER), FANCD2 (ICL repair) or SPRTN (DPC repair) carried a higher gCn→A mutation load than tumors with no deleterious mutations in these genes. Our findings demonstrate that multiple DNA repair pathways protect against acetaldehyde-induced mutagenesis.

Systemic and Local Strategies for Primary Prevention of Breast Cancer

One in eight women will develop breast cancer in the US. For women with moderate (15-20%) to average (12.5%) risk of breast cancer, there are few options available for risk reduction. For high-risk (>20%) women, such as BRCA mutation carriers, primary prevention strategies are limited to evidence-based surgical removal of breasts and/or ovaries and anti-estrogen treatment. Despite their effectiveness in risk reduction, not many high-risk individuals opt for surgical or hormonal interventions due to severe side effects and potentially life-changing outcomes as key deterrents. Thus, better communication about the benefits of existing strategies and the development of new strategies with minimal side effects are needed to offer women adequate risk-reducing interventions. We extensively review and discuss innovative investigational strategies for primary prevention. Most of these investigational strategies are at the pre-clinical stage, but some are already being evaluated in clinical trials and others are expected to lead to first-in-human clinical trials within 5 years. Likely, these strategies would be initially tested in high-risk individuals but may be applicable to lower-risk women, if shown to decrease risk at a similar rate to existing strategies, but with minimal side effects.

DNA damage and transcription stress

Genome damage and transcription are intimately linked. Tens to hundreds of thousands of DNA lesions arise in each cell each day, many of which can directly or indirectly impede transcription. Conversely, the process of gene expression is itself a source of endogenous DNA lesions as a result of the susceptibility of single-stranded DNA to damage, conflicts with the DNA replication machinery, and engagement by cells of topoisomerases and base excision repair enzymes to regulate the initiation and progression of gene transcription. Although such processes are tightly regulated and normally accurate, on occasion, they can become abortive and leave behind DNA breaks that can drive genome rearrangements, instability, or cell death.

Stress, epigenetics, and aging: Unraveling the intricate crosstalk

Aging, as a complex process involving multiple cellular and molecular pathways, is known to be exacerbated by various stresses. Because responses to these stresses, such as oxidative stress and genotoxic stress, are known to interplay with the epigenome and thereby contribute to the development of age-related diseases, investigations into how such epigenetic mechanisms alter gene expression and maintenance of cellular homeostasis is an active research area. In this review, we highlight recent studies investigating the intricate relationship between stress and aging, including its underlying epigenetic basis; describe different types of stresses that originate from both internal and external stimuli; and discuss potential interventions aimed at alleviating stress and restoring epigenetic patterns to combat aging or age-related diseases. Additionally, we address the challenges currently limiting advancement in this burgeoning field.

Ethanol induces replication fork stalling and membrane stress in immortalized laryngeal cells

Although ethanol is a class I carcinogen and is linked to more than 700,000 cancer incidences, a clear understanding of the molecular mechanisms underlying ethanol-related carcinogenesis is still lacking. Further understanding of ethanol-related cell damage can contribute to reducing or treating alcohol-related cancers. Here, we investigated the effects of both short- and long-term exposure of human laryngeal epithelial cells to different ethanol concentrations. RNA sequencing shows that ethanol altered gene expression patterns in a time- and concentration-dependent way, affecting genes involved in ribosome biogenesis, cytoskeleton remodeling, Wnt signaling, and transmembrane ion transport. Additionally, ethanol induced a slower cell proliferation, a delayed cell cycle progression, and replication fork stalling. In addition, ethanol exposure resulted in morphological changes, which could be associated with membrane stress. Taken together, our data yields a comprehensive view of molecular changes associated with ethanol stress in epithelial cells of the upper aerodigestive tract.

Bidirectional interplay between metabolism and epigenetics in hematopoietic stem cells and leukemia

During the last decades, remarkable progress has been made in further understanding the complex molecular regulatory networks that maintain hematopoietic stem cell (HSC) function. Cellular and organismal metabolisms have been shown to directly instruct epigenetic alterations, and thereby dictate stem cell fate, in the bone marrow. Epigenetic regulatory enzymes are dependent on the availability of metabolites to facilitate DNA- and histone-modifying reactions. The metabolic and epigenetic features of HSCs and their downstream progenitors can be significantly altered by environmental perturbations, dietary habits, and hematological diseases. Therefore, understanding metabolic and epigenetic mechanisms that regulate healthy HSCs can contribute to the discovery of novel metabolic therapeutic targets that specifically eliminate leukemia stem cells while sparing healthy HSCs. Here, we provide an in-depth review of the metabolic and epigenetic interplay regulating hematopoietic stem cell fate. We discuss the influence of metabolic stress stimuli, as well as alterations occurring during leukemic development. Additionally, we highlight recent therapeutic advancements toward eradicating acute myeloid leukemia cells by intervening in metabolic and epigenetic pathways.

RNF14-dependent atypical ubiquitylation promotes translation-coupled resolution of RNA-protein crosslinks

Reactive aldehydes are abundant endogenous metabolites that challenge homeostasis by crosslinking cellular macromolecules. Aldehyde-induced DNA damage requires repair to prevent cancer and premature aging, but it is unknown whether cells also possess mechanisms that resolve aldehyde-induced RNA lesions. Here, we establish photoactivatable ribonucleoside-enhanced crosslinking (PAR-CL) as a model system to study RNA crosslinking damage in the absence of confounding DNA damage in human cells. We find that such RNA damage causes translation stress by stalling elongating ribosomes, which leads to collisions with trailing ribosomes and activation of multiple stress response pathways. Moreover, we discovered a translation-coupled quality control mechanism that resolves covalent RNA-protein crosslinks. Collisions between translating ribosomes and crosslinked mRNA-binding proteins trigger their modification with atypical K6- and K48-linked ubiquitin chains. Ubiquitylation requires the E3 ligase RNF14 and leads to proteasomal degradation of the protein adduct. Our findings identify RNA lesion-induced translational stress as a central component of crosslinking damage.

K6-linked ubiquitylation marks formaldehyde-induced RNA-protein crosslinks for resolution

Reactive aldehydes are produced by normal cellular metabolism or after alcohol consumption, and they accumulate in human tissues if aldehyde clearance mechanisms are impaired. Their toxicity has been attributed to the damage they cause to genomic DNA and the subsequent inhibition of transcription and replication. However, whether interference with other cellular processes contributes to aldehyde toxicity has not been investigated. We demonstrate that formaldehyde induces RNA-protein crosslinks (RPCs) that stall the ribosome and inhibit translation in human cells. RPCs in the messenger RNA (mRNA) are recognized by the translating ribosomes, marked by atypical K6-linked ubiquitylation catalyzed by the RING-in-between-RING (RBR) E3 ligase RNF14, and subsequently resolved by the ubiquitin- and ATP-dependent unfoldase VCP. Our findings uncover an evolutionary conserved formaldehyde-induced stress response pathway that protects cells against RPC accumulation in the cytoplasm, and they suggest that RPCs contribute to the cellular and tissue toxicity of reactive aldehydes.

How nutrition regulates hematopoietic stem cell features

Our dietary choices significantly impact all the cells in our body. Increasing evidence suggests that diet-derived metabolites influence hematopoietic stem cell (HSC) metabolism and function, thereby actively modulating blood homeostasis. This is of particular relevance because regulating the metabolic activity of HSCs is crucial for maintaining stem cell fitness and mitigating the risk of hematologic disorders. In this review, we examine the current scientific knowledge of the impact of diet on stemness features, and we specifically highlight the established mechanisms by which dietary components modulate metabolic and transcriptional programs in adult HSCs. Gaining a deeper understanding of how nutrition influences our HSC compartment may pave the way for targeted dietary interventions with the potential to decelerate aging and improve the effectiveness of transplantation and cancer therapies.

Aged hematopoietic stem cells entrap regulatory T cells to create a prosurvival microenvironment

Although DNA mutation drives stem cell aging, how mutation-accumulated stem cells obtain clonal advantage during aging remains poorly understood. Here, using a mouse model of irradiation-induced premature aging and middle-aged mice, we show that DNA mutation accumulation in hematopoietic stem cells (HSCs) during aging upregulates their surface expression of major histocompatibility complex class II (MHCII). MHCII upregulation increases the chance for recognition by bone marrow (BM)-resident regulatory T cells (Tregs), resulting in their clonal expansion and accumulation in the HSC niche. On the basis of the establishment of connexin 43 (Cx43)-mediated gap junctions, BM Tregs transfer cyclic adenosine monophosphate (cAMP) to aged HSCs to diminish apoptotic priming and promote their survival via activation of protein kinase A (PKA) signaling. Importantly, targeting the HSC-Treg interaction or depleting Tregs effectively prevents the premature/physiological aging of HSCs. These findings show that aged HSCs use an active self-protective mechanism by entrapping local Tregs to construct a prosurvival niche and obtain a clonal advantage.

Cancers make their own luck: theories of cancer origins

Cancer has been a leading cause of death for decades. This dismal statistic has increased efforts to prevent the disease or to detect it early, when treatment is less invasive, relatively inexpensive and more likely to cure. But precisely how tissues are transformed continues to provoke controversy and debate, hindering cancer prevention and early intervention strategies. Various theories of cancer origins have emerged, including the suggestion that it is 'bad luck': the inevitable consequence of random mutations in proliferating stem cells. In this Review, we discuss the principal theories of cancer origins and the relative importance of the factors that underpin them. The body of available evidence suggests that developing and ageing tissues 'walk a tightrope', retaining adequate levels of cell plasticity to generate and maintain tissues while avoiding overstepping into transformation. Rather than viewing cancer as 'bad luck', understanding the complex choreography of cell intrinsic and extrinsic factors that characterize transformation holds promise to discover effective new ways to prevent, detect and stop cancer before it becomes incurable.

Stress mechanism involved in the progression of alcoholic liver disease and the therapeutic efficacy of nanoparticles

Alcoholic liver disease (ALD) poses a significant threat to human health, with excessive alcohol intake disrupting the immunotolerant environment of the liver and initiating a cascade of pathological events. This progressive disease unfolds through fat deposition, proinflammatory cytokine upregulation, activation of hepatic stellate cells, and eventual development of end-stage liver disease, known as hepatocellular carcinoma (HCC). ALD is intricately intertwined with stress mechanisms such as oxidative stress mediated by reactive oxygen species, endoplasmic reticulum stress, and alcohol-induced gut dysbiosis, culminating in increased inflammation. While the initial stages of ALD can be reversible with diligent care and abstinence, further progression necessitates alternative treatment approaches. Herbal medicines have shown promise, albeit limited by their poor water solubility and subsequent lack of extensive exploration. Consequently, researchers have embarked on a quest to overcome these challenges by delving into the potential of nanoparticle-mediated therapy. Nanoparticle-based treatments are being explored for liver diseases that share similar mechanisms with alcoholic liver disease. It underscores the potential of these innovative approaches to counteract the complex pathogenesis of ALD, providing new avenues for therapeutic intervention. Nevertheless, further investigations are imperative to fully unravel the therapeutic potential and unlock the promise of nanoparticle-mediated therapy specifically tailored for ALD treatment.

Stress mechanism involved in the progression of alcoholic liver disease and the therapeutic efficacy of nanoparticles

Alcoholic liver disease (ALD) poses a significant threat to human health, with excessive alcohol intake disrupting the immunotolerant environment of the liver and initiating a cascade of pathological events. This progressive disease unfolds through fat deposition, proinflammatory cytokine upregulation, activation of hepatic stellate cells, and eventual development of end-stage liver disease, known as hepatocellular carcinoma (HCC). ALD is intricately intertwined with stress mechanisms such as oxidative stress mediated by reactive oxygen species, endoplasmic reticulum stress, and alcohol-induced gut dysbiosis, culminating in increased inflammation. While the initial stages of ALD can be reversible with diligent care and abstinence, further progression necessitates alternative treatment approaches. Herbal medicines have shown promise, albeit limited by their poor water solubility and subsequent lack of extensive exploration. Consequently, researchers have embarked on a quest to overcome these challenges by delving into the potential of nanoparticle-mediated therapy. Nanoparticle-based treatments are being explored for liver diseases that share similar mechanisms with alcoholic liver disease. It underscores the potential of these innovative approaches to counteract the complex pathogenesis of ALD, providing new avenues for therapeutic intervention. Nevertheless, further investigations are imperative to fully unravel the therapeutic potential and unlock the promise of nanoparticle-mediated therapy specifically tailored for ALD treatment.

Comprehensive single-cell genome analysis at nucleotide resolution using the PTA Analysis Toolbox

Detection of somatic mutations in single cells has been severely hampered by technical limitations of whole-genome amplification. Novel technologies including primary template-directed amplification (PTA) significantly improved the accuracy of single-cell whole-genome sequencing (WGS) but still generate hundreds of artifacts per amplification reaction. We developed a comprehensive bioinformatic workflow, called the PTA Analysis Toolbox (PTATO), to accurately detect single base substitutions, insertions-deletions (indels), and structural variants in PTA-based WGS data. PTATO includes a machine learning approach and filtering based on recurrence to distinguish PTA artifacts from true mutations with high sensitivity (up to 90%), outperforming existing bioinformatic approaches. Using PTATO, we demonstrate that hematopoietic stem cells of patients with Fanconi anemia, which cannot be analyzed using regular WGS, have normal somatic single base substitution burdens but increased numbers of deletions. Our results show that PTATO enables studying somatic mutagenesis in the genomes of single cells with unprecedented sensitivity and accuracy.

Deconvoluting gene and environment interactions to develop an "epigenetic score meter" of disease

Human health is determined both by genetics (G) and environment (E). This is clearly illustrated in groups of individuals who are exposed to the same environmental factor showing differential responses. A quantitative measure of the gene-environment interactions (GxE) effects has not been developed and in some instances, a clear consensus on the concept has not even been reached; for example, whether cancer is predominantly emerging from "bad luck" or "bad lifestyle" is still debated. In this article, we provide a panel of examples of GxE interaction as drivers of pathogenesis. We highlight how epigenetic regulations can represent a common connecting aspect of the molecular bases. Our argument converges on the concept that the GxE is recorded in the cellular epigenome, which might represent the key to deconvolute these multidimensional intricated layers of regulation. Developing a key to decode this epigenetic information would provide quantitative measures of disease risk. Analogously to the epigenetic clock introduced to estimate biological age, we provocatively propose the theoretical concept of an "epigenetic score-meter" to estimate disease risk.

Epidemiology and Risk Factors for Breast Cancer: 21st Century Advances, Gaps to Address through Interdisciplinary Science

Research methods to study risk factors and prevention of breast cancer have evolved rapidly. We focus on advances from epidemiologic studies reported over the past two decades addressing scientific discoveries, as well as their clinical and public health translation for breast cancer risk reduction. In addition to reviewing methodology advances such as widespread assessment of mammographic density and Mendelian randomization, we summarize the recent evidence with a focus on the timing of exposure and windows of susceptibility. We summarize the implications of the new evidence for application in risk stratification models and clinical translation to focus prevention-maximizing benefits and minimizing harm. We conclude our review identifying research gaps. These include: pathways for the inverse association of vegetable intake and estrogen receptor (ER)-ve tumors, prepubertal and adolescent diet and risk, early life adiposity reducing lifelong risk, and gaps from changes in habits (e.g., vaping, binge drinking), and environmental exposures.

FAAP100 is required for the resolution of transcription-replication conflicts in primordial germ cells

BACKGROUND

The maintenance of genome stability in primordial germ cells (PGCs) is crucial for the faithful transmission of genetic information and the establishment of reproductive reserve. Numerous studies in recent decades have linked the Fanconi anemia (FA) pathway with fertility, particularly PGC development. However, the role of FAAP100, an essential component of the FA core complex, in germ cell development is unexplored.

RESULTS

We find that FAAP100 plays an essential role in R-loop resolution and replication fork protection to counteract transcription-replication conflicts (TRCs) during mouse PGC proliferation. FAAP100 deletion leads to FA pathway inactivation, increases TRCs as well as cotranscriptional R-loops, and contributes to the collapse of replication forks and the generation of DNA damage. Then, the activated p53 signaling pathway triggers PGC proliferation defects, ultimately resulting in insufficient establishment of reproductive reserve in both sexes of mice.

CONCLUSIONS

Our findings suggest that FAAP100 is required for the resolution of TRCs in PGCs to safeguard their genome stability.

Chemical sensors for imaging total cellular aliphatic aldehydes in live cells

Aliphatic aldehydes are reactive electrophilic carbonyls that cross-link with DNA and proteins leading to cellular toxicity and disease pathogenesis. This toxicity is due to the cooperative effect of multiple aldehydes via a common mechanism. Therefore, live-cell imaging of total aliphatic aldehydes, small-to-long chain (C1-C10), is highly desired to decipher their physiological and pathological functions. However, sensors for imaging total cellular aliphatic aldehydes are currently lacking despite their high concentrations (∼80 to >500 μM) inside cells. Herein, we report chemical sensors that generate a benzimidazole moiety upon reaction with aliphatic aldehydes of different chain lengths (C1-C10), resulting in turn-on fluorescence. These sensors exhibit high quantum yields, high dynamic range, and enable the quantification of changes in both the exogenous administration of aldehydes and endogenous real-time formation of aliphatic aldehydes in live mammalian cells. This tool has great potential to transform aldehyde research by illuminating cellular metabolites that have remained elusive in living systems.

Phosphorylation by ATR triggers FANCD2 chromatin loading and activates the Fanconi anemia pathway

The Fanconi anemia (FA) pathway repairs DNA interstrand crosslinks (ICLs) in humans. Activation of the pathway relies on loading of the FANCD2/FANCI complex onto chromosomes, where it is fully activated by subsequent monoubiquitination. However, the mechanism for loading the complex onto chromosomes remains unclear. Here, we identify 10 SQ/TQ phosphorylation sites on FANCD2, which are phosphorylated by ATR in response to ICLs. Using a range of biochemical assays complemented with live-cell imaging including super-resolution single-molecule tracking, we show that these phosphorylation events are critical for loading of the complex onto chromosomes and for its subsequent monoubiquitination. We uncover how the phosphorylation events are tightly regulated in cells and that mimicking their constant phosphorylation leads to an uncontrolled active state of FANCD2, which is loaded onto chromosomes in an unrestrained fashion. Taken together, we describe a mechanism where ATR triggers FANCD2/FANCI loading onto chromosomes.

Genotoxic aldehyde stress prematurely ages hematopoietic stem cells in a p53-driven manner

Aged hematopoietic stem cells (HSCs) display diminished self-renewal and a myeloid differentiation bias. However, the drivers and mechanisms that underpin this fundamental switch are not understood. HSCs produce genotoxic formaldehyde that requires protection by the detoxification enzymes ALDH2 and ADH5 and the Fanconi anemia (FA) DNA repair pathway. We find that the HSCs in young Aldh2-/-Fancd2-/- mice harbor a transcriptomic signature equivalent to aged wild-type HSCs, along with increased epigenetic age, telomere attrition, and myeloid-biased differentiation quantified by single HSC transplantation. In addition, the p53 response is vigorously activated in Aldh2-/-Fancd2-/- HSCs, while p53 deletion rescued this aged HSC phenotype. To further define the origins of the myeloid differentiation bias, we use a GFP genetic reporter to find a striking enrichment of Vwf+ myeloid and megakaryocyte-lineage-biased HSCs. These results indicate that metabolism-derived formaldehyde-DNA damage stimulates the p53 response in HSCs to drive accelerated aging.

A C57BL/6J Fancg-KO Mouse Model Generated by CRISPR/Cas9 Partially Captures the Human Phenotype

Fanconi anemia (FA) develops due to a mutation in one of the FANC genes that are involved in the repair of interstrand crosslinks (ICLs). FANCG, a member of the FA core complex, is essential for ICL repair. Previous FANCG-deficient mouse models were generated with drug-based selection cassettes in mixed mice backgrounds, leading to a disparity in the interpretation of genotype-related phenotype. We created a Fancg-KO (KO) mouse model using CRISPR/Cas9 to exclude these confounders. The entire Fancg locus was targeted and maintained on the immunological well-characterized C57BL/6J background. The intercrossing of heterozygous mice resulted in sub-Mendelian numbers of homozygous mice, suggesting the loss of FANCG can be embryonically lethal. KO mice displayed infertility and hypogonadism, but no other developmental problems. Bone marrow analysis revealed a defect in various hematopoietic stem and progenitor subsets with a bias towards myelopoiesis. Cell lines derived from Fancg-KO mice were hypersensitive to the crosslinking agents cisplatin and Mitomycin C, and Fancg-KO mouse embryonic fibroblasts (MEFs) displayed increased γ-H2AX upon cisplatin treatment. The reconstitution of these MEFs with Fancg cDNA corrected for the ICL hypersensitivity. This project provides a new, genetically, and immunologically well-defined Fancg-KO mouse model for further in vivo and in vitro studies on FANCG and ICL repair.

Aldehyde-Associated Mutagenesis─Current State of Knowledge

Aldehydes are widespread in the environment, with multiple sources such as food and beverages, industrial effluents, cigarette smoke, and additives. The toxic effects of exposure to several aldehydes have been observed in numerous studies. At the molecular level, aldehydes damage DNA, cross-link DNA and proteins, lead to lipid peroxidation, and are associated with increased disease risk including cancer. People genetically predisposed to aldehyde sensitivity exhibit severe health outcomes. In various diseases such as Fanconi's anemia and Cockayne syndrome, loss of aldehyde-metabolizing pathways in conjunction with defects in DNA repair leads to widespread DNA damage. Importantly, aldehyde-associated mutagenicity is being explored in a growing number of studies, which could offer key insights into how they potentially contribute to tumorigenesis. Here, we review the genotoxic effects of various aldehydes, focusing particularly on the DNA adducts underlying the mutagenicity of environmentally derived aldehydes. We summarize the chemical structures of the aldehydes and their predominant DNA adducts, discuss various methodologies, in vitro and in vivo, commonly used in measuring aldehyde-associated mutagenesis, and highlight some recent studies looking at aldehyde-associated mutation signatures and spectra. We conclude the Review with a discussion on the challenges and future perspectives of investigating aldehyde-associated mutagenesis.

Analysis of Aldehyde Dehydrogenase 2 as a Prognostic Marker Associated with Immune Cell infiltration and Chemotherapy Efficacy in Head and Neck Squamous Cell Carcinoma

Background: Previous investigations have demonstrated the role of Aldehyde Dehydrogenase 2 (ALDH2) levels in the cancer initiation and progression, prognosis, and treatment response in kinds of malignancies. However, its significance in the head and neck squamous cell carcinoma (HNSC) by different human papillomavirus (HPV) statuses remains unclear. Methods: We conducted an in-depth analysis of ALDH2 in HNSC using various bioinformatics tools, investigating its expression, alteration, differential levels, prognostic significance, molecular interactions, immune characteristics, and conducting experimental validation through immunohistochemistry (IHC) arrays and Western blot to compare expression levels between tumor and normal tissues, analyze the associations with clinicopathological features, and investigate its responses to chemotherapies. Results: ALDH2 levels are downregulated in HNSC tissues and associated with higher American Joint Committee on Cancer (AJCC) T classification and worse overall survival in HPV-unrelated HNSC, yet not in HPV-related HNSC. ALDH2 is positively regulated by copy-number variation and negatively regulated by DNA methylation. The association of ALDH2 with prognosis may be due to its interaction with ALDH6A1, and its co-expressed genes are predictive biomarkers of HNSC. We also found high ALDH2 levels in bulk tumors are associated with increased immune surveillance cells, such as naïve B cells and M1 macrophages in HPV-unrelated HNSC. IHC and western blot showed that ALDH2 is downregulated in the oral cavity, hypopharyngeal cancers, and well-differentiated carcinoma. In vitro, low ALDH2 levels showed reduced response to 5-fluorouracil in HNSC-derived cell lines. Conclusion: Our analyses revealed the genetic and cellular targets and drug response of ALDH2 in HNSC. We also found ALDH2 is involved in regulating the immune response of the tumor microenvironment, and high levels of ALDH2 in bulk HNSC may enhance antitumor immunity, which could improve prognosis. These findings suggest that ALDH2 could be a potential biomarker in improving risk stratification and tailoring treatment strategies in HNSC patients, especially in the HPV-unrelated subgroup.