Clonal hematopoiesis and nonhematologic disorders

RNA sequence analysis of somatic mutations in aging and Parkinson's Disease

Parkinson's Disease (PD) is an age-related neurodegenerative disorder that has been associated with increased DNA damage. To test if PD is associated with increased somatic mutations, we analyzed RNA-seq data in whole blood from 5 visits of the Parkinson's Progression Markers Initiative for clonally amplified somatic variants. Comprehensive analysis of RNA-sequencing data revealed a total of 5,927 somatic variants (2.4 variants per sample on average). Mutation frequencies were significantly elevated in PD subjects as compared to age-matched controls at the time of the last visit. This was confirmed by RNA analysis of substantia nigra. By contrast, the fraction of carriers with clonal hematopoiesis, was significantly reduced in old PD patients as compared to old healthy controls. These results indicate that while the overall mutation rate is higher in PD, specific clonally amplified mutations are protective against PD, as has been found for Alzheimer's Disease.

The ultrafine powder of atractylodis macrocephalae rhizoma improves immune function in naturally aging rats by regulating the PI3K/Akt/NF-κB signaling pathway

Background

The phenomenon of population aging presents a significant global challenge, with the aging population in China steadily increasing. As individuals progress in age, there is a gradual deterioration of human organs and systems, as well as a decline in the immune system, referred to as immunosenescence. Atractylodis macrocephalae rhizoma (BZ) has been historically used in China for its medicinal properties, including gastrointestinal improvement, immunomodulation, anti-aging, antioxidant effects, and anti-tumor effects. Nevertheless, there remains a gap in understanding the pharmacological and molecular mechanisms underlying its anti-immunosenescence effects.

Methods

This study employed UPLC-ESI-MS and network pharmacology to create a network map of BZ ultrafine powder (BZU) and its aging targets. Enrichment analysis was then used to identify the primary mechanistic pathways underlying BZU's anti-immunosenescence effects. The primary components of BZU were quantitatively analyzed using high-performance liquid chromatography (HPLC). Naturally aging rats were used to examine the effects of different oral doses (0.25, 0.5, and 1 g/kg) of BZU over 5 weeks on aging performance, peripheral blood immunophenotyping and cell count, and splenic lymphocyte proliferation rate. To validate the findings of network pharmacology, quantitative RT-PCR, Western blotting, and immunofluorescence analyses were conducted.

Results

Our analyses demonstrated that BZU improved various indicators of aging in naturally aging rats, such as increasing the number of voluntary activities, enhance grip strength and fatigue resistance, increasing the microcirculatory blood flow and improving hematological levels. The BZU administration enhanced T and B lymphocyte proliferation and significantly improved the lymphocyte-to-T cell subpopulation ratio. It can elevate serum IL-2 and IL-4 levels while reducing IL-6, IFN-γ and TNF-α levels in naturally aging rats. Finally, it increased CD3 protein expression in the spleen while decreasing protein levels of PI3K, p-AKT, IKKα/β, and NF-κB. It also decreased the mRNA expression of Pik3cg, Akt1, Pdk1 and Nfκb1.

Conclusion

These findings suggest that BZU may enhance lymphocyte proliferation by inhibiting the PI3K/Akt/NF-κB signaling pathway, correcting immune cell imbalances, reducing inflammatory responses, and ultimately enhancing immune function and potentially delaying aging.

Clonal hematopoiesis of indeterminate potential: contribution to disease and promising interventions

In clonal hematopoiesis of indeterminate potential (CHIP), subpopulations of blood cells carrying somatic mutations expand as the individual ages, and this expansion may elevate risk of blood cancers as well as cardiovascular disease. Individuals at higher risk of CHIP and therefore of CHIP-associated disease can be identified through mutational profiling, and the apparently central role of inflammation in CHIP-associated disease has emerged as a potential therapeutic target. While CHIP is often associated with negative health outcomes, emerging evidence suggests that some CHIP-related mutations may also exert beneficial effects, indicating a more complex role in human health. This review examines current understanding of the epidemiology and clinical significance of CHIP and the role of inflammation in driving its association with disease risk. It explores the mechanisms linking CHIP to inflammation and risk of cardiovascular and other diseases, as well as the potential of personalizing therapies against those diseases for individuals with CHIP.

Clonal hematopoiesis: elements associated with clonal expansion and diseases

Clonal hematopoiesis (CH), characterized by the expansion of hematopoietic stem and progenitor cells harboring somatic mutations, has emerged as a significant age-related phenomenon with profound implications for human health. While initially recognized in the 1960s, recent technological advances have revealed its complex nature and widespread prevalence, affecting up to 84% of individuals aged ≥ 70 years. The clinical significance of CH extends beyond its well-established role as a precursor to hematological malignancies, encompassing its association with cardiovascular diseases, chronic kidney disease, and other non-malignant disorders. This comprehensive review synthesizes the current understanding of CH, focusing on recent advances in genetic and molecular mechanisms, particularly the roles of commonly mutated genes such as DNMT3A, TET2, and ASXL1. We address the emerging distinction between myeloid and lymphoid CH, their differential impacts on disease progression, and the complex interplay between CH and inflammation. Special attention is given to newly identified genetic determinants of clonal expansion rates and their implications for disease progression. The review also examines the revolutionary concept of passenger-approximated clonal expansion rate and its utility in understanding CH dynamics. Furthermore, we discuss therapeutic strategies targeting inflammatory pathways and their potential in mitigating CH-associated complications. By integrating recent findings from genetic, molecular, and clinical studies, this review provides a framework for understanding CH as a systemic condition and highlights promising directions for therapeutic interventions.

TET2 deficiency increases the competitive advantage of hematopoietic stem and progenitor cells through upregulation of thrombopoietin receptor signaling

Ten-Eleven Translocation-2 (TET2) mutations drive the expansion of mutant hematopoietic stem cells (HSCs) in clonal hematopoiesis (CH). However, the precise mechanisms by which TET2 mutations confer a competitive advantage to HSCs remain unclear. Here, through an epigenetic drug screen, we discover that inhibition of disruptor of telomeric silencing 1-like (DOT1L), a H3K79 methyltransferase, selectively reduces the fitness of Tet2 knockout (Tet2KO) hematopoietic stem and progenitor cells (HSPCs). Mechanistically, we find that TET2 deficiency increases H3K79 dimethylation and expression of Mpl, which encodes the thrombopoietin receptor (TPO-R). Correspondingly, TET2 deficiency is associated with a higher proportion of primitive Mpl-expressing (Mpl+) cells in the HSC compartment. Importantly, inhibition of Mpl expression or the signaling downstream of TPO-R is sufficient to reduce the competitive advantage of murine and human TET2-deficient HSPCs. Our findings demonstrate a critical role for aberrant TPO-R signaling in TET2 mutation-driven CH and uncover potential therapeutic strategies against this condition.

Hematopoietic stem cell transplantation and immunosuppressive therapy: implications of clonal haematopoiesis

Aplastic anemia (AA) is a life-threatening bone marrow failure syndrome. The advent of next-generation sequencing (NGS) has shed light on the link between somatic mutations (SM) and the efficacy of immunosuppressive therapy (IST) in AA patients. However, the relationship between SM and hematopoietic stem cell transplantation (HSCT) has not been extensively explored. In this retrospective analysis, we examined 166 AA patients who received HSCT or IST at our institution between May 2019 and December 2023. NGS was conducted on 66 genes within bone marrow cells to investigate the correlation between SM and the prognosis and therapeutic response in AA patients, as well as to assess the impact of mutation types on HSCT outcomes. Clinical data were gathered from 166 AA patients, comprising 84 males and 82 females, with a median age of 32 years (ranging from 9 to 75 years). In our study, a total of 151 somatic mutations were identified across 84 patients (50.6%), with 42 patients (25.3%) presenting a single mutation and 26 patients (15.7%) harboring two mutations. The top five genes with the highest mutation frequency were BCOR/BCORL1 (12.6%), ASXL1 (8.6%), TET2 (6.6%), CEBPA (5.3%), and GATA2 (4.6%). We stratified patients into SM and No-SM groups based on the presence of mutations and further divided them into HSCT and IST groups to assess the influence of mutation types on treatment response and survival within and between these groups. The findings were as follows: 1.Patients in the HSCT group exhibited a higher treatment response (OR 85.9% vs. 68.4%, p < 0.05), although there was no significant difference in survival. 2.Patients with favorable mutations, such as PIGA and BCOR/BCORL1, experienced significantly improved response and survival compared to those with unfavorable mutations like ASXL1, DNMT3A, and TET2 (OR 93.7% vs. 72%, p < 0.05) (3-year OS 93.7% vs. 80%, p > 0.05). 3.The HSCT-Favorable group demonstrated superior response rates (OR 100% vs. 67.7%, p < 0.05) and longer survival (3-year OS 100% vs. 67.7%, p < 0.05) compared to the IST-Favorable group. This study underscores that AA patients carrying favorable mutations, particularly BCOR/BCORL1, tend to have a more robust response and better prognosis than those without mutations or those with unfavorable mutations, such as ASXL1/DNMT3A. These findings are especially pertinent to HSCT, highlighting the importance of NGS prior to initiating treatment.

Genomic instability and genetic heterogeneity in aging: insights from clonal hematopoiesis (CHIP), monoclonal gammopathy (MGUS), and monoclonal B-cell lymphocytosis (MBL)

Aging is a multifaceted process characterized by a gradual decline in physiological function and increased susceptibility to a range of chronic diseases. Among the molecular and cellular mechanisms driving aging, genomic instability is a fundamental hallmark, contributing to increased mutation load and genetic heterogeneity within cellular populations. This review explores the role of genomic instability and genetic heterogeneity in aging in the hematopoietic system, with a particular focus on clonal hematopoiesis of indeterminate potential (CHIP), monoclonal gammopathy of undetermined significance (MGUS), and monoclonal B-cell lymphocytosis (MBL) as biomarkers. CHIP involves the clonal expansion of hematopoietic stem cells with somatic mutations. In contrast, MGUS is characterized by the presence of clonal plasma cells producing monoclonal immunoglobulins, while MBL is characterized by clonal proliferation of B cells. These conditions are prevalent in the aging population and serve as measurable indicators of underlying genomic instability. Studying these entities offers valuable insights into the mechanisms by which somatic mutations accumulate and drive clonal evolution in the hematopoietic system, providing a deeper understanding of how aging impacts cellular and tissue homeostasis. In summary, the hematopoietic system serves as a powerful model for investigating the interplay between genomic instability and aging. Incorporating age-related hematological conditions into aging research, alongside other biomarkers such as epigenetic clocks, can enhance the precision and predictive power of biological age assessments. These biomarkers provide a comprehensive view of the aging process, facilitating the early detection of age-related diseases and hopefully enabling personalized healthcare strategies.

Effects of donor-engrafted clonal hematopoiesis in allogeneic and autologous stem cell transplantation: a systematic review and meta-analysis

Donor stem cell health may be critically important to the success of hematopoietic stem cell transplantation (HSCT). Herein, we performed this systematic review and meta-analysis including meta-regression to assess the impact of donor-engrafted clonal hematopoiesis (CH) in allogeneic HSCT (allo-HSCT) and impact of pre-transplant CH in autologous HSCT (auto-HSCT). We applied random-effects models to analyze 5 allo-HSCT studies with 3192 donor-recipient pairs and 9 auto-HSCT studies with 2854 patients. We found that donor-engrafted CH after allo-HSCT decreased the risk of disease relapse [Hazard Ratio (HR) = 0.79, 95% Confidence Interval (CI): (0.67, 0.93)], but did not affect overall survival (OS) [HR = 0.91, 95% CI: (0.75, 1.11)], progression-free survival (PFS) [HR = 0.94, 95% CI: (0.63, 1.41)], or non-relapse mortality [HR = 1.06, 95% CI: (0.81, 1.39)]. In contrast, pre-transplant CH in auto-HSCT recipients resulted in inferior OS [HR = 1.30, 95% CI: (1.16, 1.46)], inferior PFS [HR = 1.35, 95% CI: (1.18, 1.54)], and higher risk for therapy-related myeloid neoplasm [HR = 4.85, 95% CI: (2.39, 9.82)] when compared to auto-HSCT recipients without CH. This study sheds light onto the debate about prospective "CHIP screening" for stem cell donors and addresses the impact of CH as a transmissible phenomenon.

Parkinson's disease is associated with clonal hematopoiesis with TET2 mutation

Clonal hematopoiesis of indeterminate potential (CHIP), a premalignant expansion of mutated hematopoietic stem cells, is linked to immune alterations. Given the role of neuroinflammation and immune dysfunction in Parkinson's disease (PD), we hypothesized a connection between CHIP and PD. We analyzed peripheral blood DNA from 341 PD, 92 isolated REM sleep behavior disorder (iRBD) patients, and 5003 controls using targeted sequencing of 24 genes associated with hematologic neoplasms. PD cases were classified by clinical progression mode: fast, slow, and typical. Using multivariable logistic regression models, CHIP prevalence was assessed against controls with a 1.0% variant allele fraction threshold. CHIP with TET2 mutations was more prevalent in PD than controls (aOR 1.75, 95% CI 1.11-2.77, p = 0.017), particularly in the fast motor progression subgroup (aOR 3.19, p = 0.004). No distinct associations were observed with iRBD. PD is linked to increased odds of CHIP with TET2 mutations, suggesting immune dysregulation in PD pathophysiology.

Genetic architecture of telomere length in 462,666 UK Biobank whole-genome sequences

Telomeres protect chromosome ends from damage and their length is linked with human disease and aging. We developed a joint telomere length metric, combining quantitative PCR and whole-genome sequencing measurements from 462,666 UK Biobank participants. This metric increased SNP heritability, suggesting that it better captures genetic regulation of telomere length. Exome-wide rare-variant and gene-level collapsing association studies identified 64 variants and 30 genes significantly associated with telomere length, including allelic series in ACD and RTEL1. Notably, 16% of these genes are known drivers of clonal hematopoiesis-an age-related somatic mosaicism associated with myeloid cancers and several nonmalignant diseases. Somatic variant analyses revealed gene-specific associations with telomere length, including lengthened telomeres in individuals with large SRSF2-mutant clones, compared with shortened telomeres in individuals with clonal expansions driven by other genes. Collectively, our findings demonstrate the impact of rare variants on telomere length, with larger effects observed among genes also associated with clonal hematopoiesis.

Cardiovascular disease and cancer: shared risk factors and mechanisms

Cardiovascular disease (CVD) and cancer are among the leading causes of morbidity and mortality globally, and these conditions are increasingly recognized to be fundamentally interconnected. In this Review, we present the current epidemiological data for each of the modifiable risk factors shared by the two diseases, including hypertension, hyperlipidaemia, diabetes mellitus, obesity, smoking, diet, physical activity and the social determinants of health. We then review the epidemiological data demonstrating the increased risk of CVD in patients with cancer, as well as the increased risk of cancer in patients with CVD. We also discuss the shared mechanisms implicated in the development of these conditions, highlighting their inherent bidirectional relationship. We conclude with a perspective on future research directions for the field of cardio-oncology to advance the care of patients with CVD and cancer.

Rare coding variant analysis for human diseases across biobanks and ancestries

Large-scale sequencing has enabled unparalleled opportunities to investigate the role of rare coding variation in human phenotypic variability. Here, we present a pan-ancestry analysis of sequencing data from three large biobanks, including the All of Us research program. Using mixed-effects models, we performed gene-based rare variant testing for 601 diseases across 748,879 individuals, including 155,236 with ancestry dissimilar to European. We identified 363 significant associations, which highlighted core genes for the human disease phenome and identified potential novel associations, including UBR3 for cardiometabolic disease and YLPM1 for psychiatric disease. Pan-ancestry burden testing represented an inclusive and useful approach for discovery in diverse datasets, although we also highlight the importance of ancestry-specific sensitivity analyses in this setting. Finally, we found that effect sizes for rare protein-disrupting variants were concordant between samples similar to European ancestry and other genetic ancestries (βDeming = 0.7-1.0). Our results have implications for multi-ancestry and cross-biobank approaches in sequencing association studies for human disease.

Considering clonal hematopoiesis of indeterminate potential in space radiation risk analysis for hematologic cancers and cardiovascular disease

BACKGROUND

Expanding human presence in space through long-duration exploration missions and commercial space operations warrants improvements in approaches for quantifying crew space radiation health risks. Currently, risk assessment models for radiogenic cancer and cardiovascular disease consider age, sex, and tobacco use, but do not incorporate other modifiable (e.g., body weight, physical activity, diet, environment) and non-modifiable individual risk factors (e.g., genetics, medical history, race/ethnicity, family history) that may greatly influence crew health both in-mission and long-term. For example, clonal hematopoiesis of indeterminate potential (CHIP) is a relatively common age-related condition that is an emerging risk factor for a variety of diseases including cardiovascular disease and cancer. CHIP carrier status may therefore exacerbate health risks associated with space radiation exposure.

METHODS

In the present study, published CHIP hazard ratios were used to modify background hazard rates for coronary heart disease, stroke, and hematologic cancers in the National Aeronautics and Space Administration space radiation risk assessment model. The risk of radiation exposure-induced death for these endpoints was projected for a future Mars exploration mission scenario.

RESULTS

Here we show appreciable increases in the lifetime risk of exposure-induced death for hematologic malignancies, coronary heart disease, and stroke, which are observed as a function of age after radiation exposure for male and female crew members that are directly attributable to the elevated health risks for CHIP carriers.

CONCLUSIONS

We discuss the importance of evaluating individual risk factors such as CHIP as part of a comprehensive space radiation risk assessment strategy aimed at effective risk communication and disease surveillance for astronauts embarking on future exploration missions.

Genomic Mosaicism of the Brain: Origin, Impact, and Utility

Genomic mosaicism describes the phenomenon where some but not all cells within a tissue harbor unique genetic mutations. Traditionally, research focused on the impact of genomic mosaicism on clinical phenotype-motivated by its involvement in cancers and overgrowth syndromes. More recently, we increasingly shifted towards the plethora of neutral mosaic variants that can act as recorders of cellular lineage and environmental exposures. Here, we summarize the current state of the field of genomic mosaicism research with a special emphasis on our current understanding of this phenomenon in brain development and homeostasis. Although the field of genomic mosaicism has a rich history, technological advances in the last decade have changed our approaches and greatly improved our knowledge. We will provide current definitions and an overview of contemporary detection approaches for genomic mosaicism. Finally, we will discuss the impact and utility of genomic mosaicism.

Putting comprehensive genomic profiling of ctDNA to work: 10 proposed use cases

Liquid biopsy profiling of circulating tumor DNA (ctDNA) has become established as a compelling, pragmatic diagnostic in the care of cancer patients and is now endorsed by multiple cancer care guidelines. Moreover, ctDNA profiling technologies have advanced significantly and offer increasingly comprehensive and reliable insights into cancer. In this review, we focus on applications of ctDNA and propose that a critical untapped opportunity is in considering how we utilize these accessible, scalable technologies across diverse potential applications. With a specific focus on clinical applications, rather than research uses, we describe 10 use cases for ctDNA profiling across four categories: (1) established and (2) emerging applications of ctDNA profiling for therapy selection, (3) incidental detection of secondary genomic findings, and (4) quantification of plasma DNA tumor content.

Massive parallel sequencing unveils homologous recombination deficiency in follicular dendritic cell sarcoma

Standardized treatment options are lacking for patients with unresectable or multifocal follicular dendritic cell sarcoma (FDCS) and disease-related mortality is as high as 20%. Applying whole-genome sequencing (WGS) in one case and whole-exome sequencing (WES) in additional twelve cases, this study adds information on the molecular landscape of FDCS, expanding knowledge on pathobiological mechanisms and identifying novel markers of potential theragnostic significance. Massive parallel sequencing showed high frequency of mutations on oncosuppressor genes, particularly in RB1, CARS and BRCA2 and unveiled alterations on homologous recombination DNA damage repair-related genes in 70% (9/13) of cases. This indicates that patients with high-stage FDCS may be eligible for poly ADP ribose polymerase inhibition protocols. Low tumor mutational burden was confirmed in this study despite common PDL1 expression in FDCS arguing on the efficacy of immune checkpoint inhibitors. CDKN2A deletion, detected by WGS and confirmed by fluorescence in situ hybridization in 41% of cases (9/22) indicates that impairment of cell cycle regulation may sustain oncogenesis in FDCS. Absence of mutations in the RAS/RAF/MAPK pathway and lack of clonal hematopoiesis-related mutations in FDCS sanction its differences from dendritic cell-derived neoplasms of hematopoietic derivation. WGS and WES in FDCS provides additional information on the molecular landscape of this rare tumor, proposing novel candidate genes for innovative therapeutical approaches to improve survival of patients with multifocal disease.

Chemoprophylaxis of precancerous lesions in patients who are at a high risk of developing colorectal cancer (Review)

The diagnostics of colorectal cancer (CRC) and precancerous lesions in the colon is one of the most urgent matters to be considered for the modern protocols of complex examination, recommended for use from the age of 45 years, and including both instrumental and laboratory methods of research: Colonoscopy, CT colonography, flexible sigmoidoscopy, fecal occult blood test, fecal immunohistochemistry test and stool DNA test Nevertheless, the removal of those precancerous lesions does not solve the issue, and, apart from the regular endoscopic monitoring of patients who are at a high risk of developing CRC, the pharmacological treatment of certain key pathogenic mechanisms leading to the development of CRC is required. The present review to discusses the function of β-catenin in the transformation of precancerous colorectal lesions into CRC, when collaborating with PI3K/AKT/mTOR signaling pathway and other mechanisms. The existing methods for the early diagnostics and prevention of discovered anomalies are described and categorized. The analysis of the approaches to chemoprophylaxis of CRC, depending on the results of endoscopic, morphological and molecular-genetic tests, is presented.

The potency of hematopoietic stem cell reprogramming for changing immune tone

Innate immune memory endows innate immune cells with antigen independent heightened responsiveness to subsequent challenges. The durability of this response can be mediated by inflammation induced epigenetic and metabolic reprogramming in hematopoietic stem and progenitor cells (HSPCs) that are maintained through differentiation to mature immune progeny. Understanding the mechanisms and extent of trained immunity induction by pathogens and vaccines, such as BCG, in HSPC remains a critical area of exploration with important implications for health and disease. Here we review these concepts and present new analysis to highlight how inflammatory reprogramming of HSPC can potently alter immune tone, including to enhance specific anti-tumor responses. New findings in the field pave the way for novel HSPC targeting therapeutic strategies in cancer and other contexts of immune modulation. Future studies are expected to unravel diverse and extensive effects of infections, vaccines, microbiota, and sterile inflammation on hematopoietic progenitor cells and begin to illuminate the broad spectrum of immunologic tuning that can be established through altering HSPC phenotypes. The purpose of this review is to draw attention to emerging and speculative topics in this field where we posit that focused study of HSPC in the framework of trained immunity holds significant promise.

Clonal Hematopoiesis of Indeterminate Potential With Loss of Tet2 Enhances Risk for Atrial Fibrillation Through Nlrp3 Inflammasome Activation

BACKGROUND

Clonal hematopoiesis of indeterminate potential (CHIP), a common age-associated phenomenon, associates with increased risk of both hematological malignancy and cardiovascular disease. Although CHIP is known to increase the risk of myocardial infarction and heart failure, the influence of CHIP in cardiac arrhythmias, such as atrial fibrillation (AF), is less explored.

METHODS

CHIP prevalence was determined in the UK Biobank, and incident AF analysis was stratified by CHIP status and clone size using Cox proportional hazard models. Lethally irradiated mice were transplanted with hematopoietic-specific loss of Tet2, hematopoietic-specific loss of Tet2 and Nlrp3, or wild-type control and fed a Western diet, compounded with or without NLRP3 (NLR [NACHT, LRR {leucine rich repeat}] family pyrin domain containing protein 3) inhibitor, NP3-361, for 6 to 9 weeks. Mice underwent in vivo invasive electrophysiology studies and ex vivo optical mapping. Cardiomyocytes from Ldlr-/- mice with hematopoietic-specific loss of Tet2 or wild-type control and fed a Western diet were isolated to evaluate calcium signaling dynamics and analysis. Cocultures of pluripotent stem cell-derived atrial cardiomyocytes were incubated with Tet2-deficient bone marrow-derived macrophages, wild-type control, or cytokines IL-1β (interleukin 1β) or IL-6 (interleukin 6).

RESULTS

Analysis of the UK Biobank showed individuals with CHIP, in particular TET2 CHIP, have increased incident AF. Hematopoietic-specific inactivation of Tet2 increases AF propensity in atherogenic and nonatherogenic mouse models and is associated with increased Nlrp3 expression and CaMKII (Ca2+/calmodulin-dependent protein kinase II) activation, with AF susceptibility prevented by inactivation of Nlrp3. Cardiomyocytes isolated from Ldlr-/- mice with hematopoietic inactivation of Tet2 and fed a Western diet have impaired calcium release from the sarcoplasmic reticulum into the cytosol, contributing to atrial arrhythmogenesis. Abnormal sarcoplasmic reticulum calcium release was recapitulated in cocultures of cardiomyocytes with the addition of Tet2-deficient macrophages or cytokines IL-1β or IL-6.

CONCLUSIONS

We identified a modest association between CHIP, particularly TET2 CHIP, and incident AF in the UK Biobank population. In a mouse model of AF resulting from hematopoietic-specific inactivation of Tet2, we propose altered calcium handling as an arrhythmogenic mechanism, dependent on Nlrp3 inflammasome activation. Our data are in keeping with previous studies of CHIP in cardiovascular disease, and further studies into the therapeutic potential of NLRP3 inhibition for individuals with TET2 CHIP may be warranted.

Radon Exposure and Incident Stroke Risk in the Women's Health Initiative

BACKGROUND AND OBJECTIVES

Little is known about the role of radon in the epidemiology of stroke among women. We therefore examined the association between home radon exposure and risk of stroke among middle-aged and older women in the United States.

METHODS

We conducted a prospective cohort study of postmenopausal women aged 50-79 years at baseline (1993-1998) in the Women's Health Initiative. We measured exposures as 2-day, indoor, lowest living-level average radon concentrations in picocuries per liter (pCi/L) as estimated in 1993 by the US Geological Survey and reviewed by the Association of American State Geologists under the Indoor Radon Abatement Act. We used Cox proportional hazards models to estimate risk of incident, neurologist-adjudicated stroke during follow-up through 2020 as a hazard ratio and 95% CI, adjusting for study design and participant demographic, social, behavioral, and clinical characteristics.

RESULTS

Among 158,910 women without stroke at baseline (mean age 63.2 years; 83% white), 6,979 incident strokes were identified over follow-up (mean 13.4 years). Incidence rates were 333, 343, and 349 strokes per 100,000 woman-years at radon concentrations of <2, 2-4, and >4 pCi/L, respectively. Compared with women living at concentrations <2 pCi/L, those at 2-4 and >4 pCi/L had higher covariate-adjusted risks of incident stroke: hazard ratio (95% CI) 1.06 (0.99-1.13) and 1.14 (1.05-1.22). Using nonlinear spline functions to model radon, stroke risk was significantly elevated at concentrations ranging from 2 to 4 pCi/L (p = 0.0004), that is, below the United States Environmental Protection Agency Radon Action Level for mitigation (4 pCi/L). Associations were slightly stronger for ischemic (especially cardioembolic, small vessel occlusive, and large artery atherosclerotic) than hemorrhagic stroke, but otherwise robust in sensitivity analyses.

DISCUSSION

Radon exposure is associated with moderately increased stroke risk among middle-aged and older women in the United States, suggesting that promulgation of a lower Radon Action Level may help reduce the domestic impact of cerebrovascular disease on public health.

Bone marrow inflammatory memory in cardiometabolic disease and inflammatory comorbidities

Cardiometabolic disorders are chief causes of morbidity and mortality, with chronic inflammation playing a crucial role in their pathogenesis. The release of differentiated myeloid cells with elevated pro-inflammatory potential, as a result of maladaptively trained myelopoiesis may be a crucial factor for the perpetuation of inflammation. Several cardiovascular risk factors, including sedentary lifestyle, unhealthy diet, hypercholesterolemia, and hyperglycemia, may modulate bone marrow hematopoietic progenitors, causing sustained functional changes that favour chronic metabolic and vascular inflammation. In the present review, we summarize recent studies that support the function of long-term inflammatory memory in progenitors of the bone marrow for the development and progression of cardiometabolic disease and related inflammatory comorbidities, including periodontitis and arthritis. We also discuss how maladaptive myelopoiesis associated with the presence of mutated hematopoietic clones, as present in clonal hematopoiesis, may accelerate atherosclerosis via increased inflammation.

Regulation of cancer stem cells and immunotherapy of glioblastoma (Review)

Glioblastoma (GB) is one of the most adverse diagnoses in oncology. Complex current treatment results in a median survival of 15 months. Resistance to treatment is associated with the presence of cancer stem cells (CSCs). The present review aimed to analyze the mechanisms of CSC plasticity, showing the particular role of β-catenin in regulating vital functions of CSCs, and to describe the molecular mechanisms of Wnt-independent increase of β-catenin levels, which is influenced by the local microenvironment of CSCs. The present review also analyzed the reasons for the low effectiveness of using medication in the regulation of CSCs, and proposed the development of immunotherapy scenarios with tumor cell vaccines, containing heterogenous cancer cells able of producing a multidirectional antineoplastic immune response. Additionally, the possibility of managing lymphopenia by transplanting hematopoietic stem cells from a healthy sibling and using clofazimine or other repurposed drugs that reduce β-catenin concentration in CSCs was discussed in the present study.

Distinct clinico-molecular arterial and venous thrombosis scores for myeloproliferative neoplasms risk stratification

Current recommended risk scores to predict thrombotic events associated with myeloproliferative neoplasms (MPN) do not discriminate between arterial and venous thrombosis despite their different physiopathology. To define novel stratification systems, we delineated a comprehensive landscape of MPN associated thrombosis across a large long-term follow-up MPN cohort. Prior arterial thrombosis, age >60 years, cardiovascular risk factors and presence of TET2 or DNMT3A mutations were independently associated with arterial thrombosis in multivariable analysis. ARTS, an ARterial Thrombosis Score, based on these four factors, defined low- (0.37% patients-year) and high-risk (1.19% patients-year) patients. ARTS performance was superior to the two-tiered conventional risk stratification in our training cohort, across all MPN subtypes, as well as in two external validation cohorts. Prior venous thrombosis and presence of a JAK2V617F mutation with a variant allelic frequency ≥50% were independently associated with venous thrombosis. The discrimination potential of VETS, a VEnous Thrombosis Score based on these two factors, was poor, similar to the two-tiered conventional risk stratification. Our study pinpoints arterial and venous thrombosis clinico-molecular differences and proposes an arterial risk score for more accurate patients' stratification. Further improvement of venous risk scores, accounting for additional factors and considering venous thrombosis as a heterogeneous entity is warranted.

Radon Exposure, Clonal Hematopoiesis, and Stroke Susceptibility in the Women's Health Initiative

BACKGROUND AND OBJECTIVES

Studies suggest that clonal hematopoiesis of indeterminate potential (CHIP) may increase risk of hematologic malignancy and cardiovascular disease, including stroke. However, few studies have investigated plausible environmental risk factors for CHIP such as radon, despite the climate-related increases in and documented infrequency of testing for this common indoor air pollutant.The purpose of this study was to estimate the risk of CHIP related to radon, an established environmental mutagen.

METHODS

We linked geocoded addresses of 10,799 Women's Health Initiative Trans-Omics for Precision Medicine (WHI TOPMed) participants to US Environmental Protection Agency-predicted, county-level, indoor average screening radon concentrations, categorized as follows: Zone 1 (>4 pCi/L), Zone 2 (2-4 pCi/L), and Zone 3 (<2 pCi/L). We defined CHIP as the presence of one or more leukemogenic driver mutations with variant allele frequency >0.02. We identified prevalent and incident ischemic and hemorrhagic strokes; subtyped ischemic stroke using Trial of ORG 10172 in Acute Stroke Treatment (TOAST) criteria; and then estimated radon-related risk of CHIP as an odds ratio (OR) and 95% CI using multivariable-adjusted, design-weighted logistic regression stratified by age, race/ethnicity, smoking status, and stroke type/subtype.

RESULTS

The percentages of participants with CHIP in Zones 1, 2, and 3 were 9.0%, 8.4%, and 7.7%, respectively (ptrend = 0.06). Among participants with ischemic stroke, Zones 2 and 1 were associated with higher estimated risks of CHIP relative to Zone 3: 1.39 (1.15-1.68) and 1.46 (1.15-1.87), but not among participants with hemorrhagic stroke: 0.98 (0.68-1.40) and 1.03 (0.70-1.52), or without stroke: 1.04 (0.74-1.46) and 0.95 (0.63-1.42), respectively (pinteraction = 0.03). Corresponding estimates were particularly high among TOAST-subtyped cardioembolism: 1.78 (1.30-2.47) and 1.88 (1.31-2.72), or other ischemic etiologies: 1.37 (1.06-1.78) and 1.50 (1.11-2.04), but not small vessel occlusion: 1.05 (0.74-1.49) and 1.00 (0.68-1.47), respectively (pinteraction = 0.10). Observed patterns of association among strata were insensitive to attrition weighting, ancestry adjustment, prevalent stroke exclusion, separate analysis of DNMT3A driver mutations, and substitution with 3 alternative estimates of radon exposure.

DISCUSSION

The robust elevation of radon-related risk of CHIP among postmenopausal women who develop incident cardioembolic stroke is consistent with a potential role of somatic genomic mutation in this societally burdensome form of cerebrovascular disease, although the mechanism has yet to be confirmed.

Neutrophil activation and clonal CAR-T re-expansion underpinning cytokine release syndrome during ciltacabtagene autoleucel therapy in multiple myeloma

Cytokine release syndrome (CRS) is the most common complication of chimeric antigen receptor redirected T cells (CAR-T) therapy. CAR-T toxicity management has been greatly improved, but CRS remains a prime safety concern. Here we follow serum cytokine levels and circulating immune cell transcriptomes longitudinally in 26 relapsed/refractory multiple myeloma patients receiving the CAR-T product, ciltacabtagene autoleucel, to understand the immunological kinetics of CRS. We find that although T lymphocytes and monocytes/macrophages are the major overall cytokine source in manifest CRS, neutrophil activation peaks earlier, before the onset of severe symptoms. Intracellularly, signaling activation dominated by JAK/STAT pathway occurred prior to cytokine cascade and displayed regular kinetic changes. CRS severity is accurately described and potentially predicted by temporal cytokine secretion signatures. Notably, CAR-T re-expansion is found in three patients, including a fatal case characterized by somatic TET2-mutation, clonal expanded cytotoxic CAR-T, broadened cytokine profiles and irreversible hepatic toxicity. Together, our findings show that a latent phase with distinct immunological changes precedes manifest CRS, providing an optimal window and potential targets for CRS therapeutic intervention and that CAR-T re-expansion warrants close clinical attention and laboratory investigation to mitigate the lethal risk.

Successful allogeneic hematopoietic stem cell transplantation for myelodysplastic neoplasms complicated with secondary pulmonary alveolar proteinosis and Behçet's disease harboring GATA2 mutation

Myelodysplastic neoplasms (MDS) are defined by cytopenia and morphologic dysplasia originating from clonal hematopoiesis. They are also frequently complicated with diseases caused by immune dysfunction, such as Behçet's disease (BD) and secondary pulmonary alveolar proteinosis (sPAP). MDS with both BD and sPAP is extremely rare, and their prognosis is poor. In addition, haploinsufficiency of the hematopoietic transcription factor gene GATA2 is recognized as a cause of familial MDS and is frequently complicated by sPAP. Herein, we report a case of MDS combined with both BD and sPAP in association with GATA2 deficiency in a Japanese woman. Because she developed progressive leukopenia and macrocytic anemia during BD treatment at the age of 61, she underwent a bone-marrow examination and was diagnosed with MDS. She subsequently developed sPAP. At the age of 63, she underwent allogeneic hematopoietic stem cell transplantation (allo-HSCT). Since allo-HSCT, she has maintained complete remission of MDS as well as the symptoms of BD and sPAP. Furthermore, we performed whole exome sequencing and identified the GATA2 Ala164Thr germline mutation. These findings suggest that patients with MDS, BD and sPAP should be considered for early allo-HSCT.

Negative Impact of TET2 Mutations on Long-Term Survival After Transcatheter Aortic Valve Replacement

Clonal hematopoiesis of indeterminate potential (CHIP) is considered as being a novel age-related risk factor for cardiovascular diseases. By capture-sequencing of a 67-gene panel, we established a large spectrum of CHIP in 258 patients with aortic valve stenosis undergoing transcatheter aortic valve replacement (TAVR) and assessed their association with long-term survival after TAVR. One or several CHIP variants in 35 genes were identified in 68% of the cohort, DNMT3A and TET2 being the 2 most frequently mutated genes. Patients carrying a TET2-CHIP-driver variant with low variant allele frequency (2%-10%) had a significant decrease in overall survival 5 years after TAVR.

Epigenetic roles in clonal hematopoiesis and aging kidney-related chronic kidney disease

Accumulation of somatic hematopoietic stem cell mutations with aging has been revealed by the recent genome-wide analysis. Clonal expansion, known as clonal hematopoiesis of indeterminate potential (CHIP), is a premalignant condition of hematological cancers. It is defined as the absence of definitive morphological evidence of a hematological neoplasm and occurrence of ≥2% of mutant allele fraction in the peripheral blood. In CHIP, the most frequently mutated genes are epigenetic regulators such as DNMT3A, TET2, and ASXL1. CHIP induces inflammation. CHIP is shown to be associated with not only hematological malignancy but also non-malignant disorders such as atherosclerosis, cardiovascular diseases and chronic liver disease. In addition, recent several large clinical trials have shown that CHIP is also the risk factor for developing chronic kidney disease (CKD). In this review article, we proposed novel findings about CHIP and CHIP related kidney disease based on the recent basic and clinical research. The possible mechanism of the kidney injury in CHIP is supposed to be due to the clonal expansion in both myeloid and lymphoid cell lines. In myeloid cell lines, the mutated macrophages increase the inflammatory cytokine level and induce chronic inflammation. It leads to epigenetic downregulation of kidney and macrophage klotho level. In lymphoid cell lines, CHIP might be related to monoclonal gammopathy of renal significance (MGRS). It describes any B cell or plasma cell clonal disorder that does not fulfill the criteria for cancer yet produces a nephrotoxic monoclonal immunoglobulin that leads to kidney injury or disease. MGRS causes M-protein related nephropathy frequently observed among aged CKD patients. It is important to consider the CHIP-related complications such as hematological malignancy, cardiovascular diseases and metabolic disorders in managing the elderly CKD patients. There are no established therapies for CHIP and CHIP-related CKD yet. However, recent studies have supported the development of effective CHIP therapies, such as blocking the expansion of aberrant HSCs and inhibiting chronic inflammation. In addition, drugs targeting the epigenetic regulation of Klotho in the kidney and macrophages might be therapeutic targets of CHIP in the kidney.

Activation of distinct inflammatory pathways in subgroups of LR-MDS

Aberrant innate immune signaling has been identified as a potential key driver of the complex pathophysiology of myelodysplastic neoplasms (MDS). This study of a large, clinically and genetically well-characterized cohort of treatment-naïve MDS patients confirms intrinsic activation of inflammatory pathways in general mediated by caspase-1, interleukin (IL)-1β and IL-18 in low-risk (LR)-MDS bone marrow and reveals a previously unrecognized heterogeneity of inflammation between genetically defined LR-MDS subgroups. Principal component analysis resolved two LR-MDS phenotypes with low (cluster 1) and high (cluster 2) levels of IL1B gene expression, respectively. Cluster 1 contained 14/17 SF3B1-mutated cases, while cluster 2 contained 8/8 del(5q) cases. Targeted gene expression analysis of sorted cell populations showed that the majority of the inflammasome-related genes, including IL1B, were primarily expressed in the monocyte compartment, consistent with a dominant role in determining the inflammatory bone marrow environment. However, the highest levels of IL18 expression were found in hematopoietic stem and progenitor cells (HSPCs). The colony forming activity of healthy donor HSPCs exposed to monocytes from LR-MDS was increased by the IL-1β-neutralizing antibody canakinumab. This work reveals distinct inflammatory profiles in LR-MDS that are of likely relevance to the personalization of emerging anti-inflammatory therapies.

Clonal Hematopoiesis of Indeterminate Potential From a Heart Failure Specialist's Point of View

Clonal hematopoiesis of indeterminate potential (CHIP) is a common bone marrow abnormality induced by age-related DNA mutations, which give rise to proinflammatory immune cells. These immune cells exacerbate atherosclerotic cardiovascular disease and may induce or accelerate heart failure. The mechanisms involved are complex but point toward a central role for proinflammatory macrophages and an inflammasome-dependent immune response (IL-1 [interleukin-1] and IL-6 [interleukin-6]) in the atherosclerotic plaque or directly in the myocardium. Intracardiac inflammation may decrease cardiac function and induce cardiac fibrosis, even in the absence of atherosclerotic cardiovascular disease. The pathophysiology and consequences of CHIP may differ among implicated genes as well as subgroups of patients with heart failure, based on cause (ischemic versus nonischemic) and ejection fraction (reduced ejection fraction versus preserved ejection fraction). Evidence is accumulating that CHIP is associated with cardiovascular mortality in ischemic and nonischemic heart failure with reduced ejection fraction and involved in the development of heart failure with preserved ejection fraction. CHIP and corresponding inflammatory pathways provide a highly potent therapeutic target. Randomized controlled trials in patients with well-phenotyped heart failure, where readily available anti-inflammatory therapies are used to intervene with clonal hematopoiesis, may pave the way for a new area of heart failure treatment. The first clinical trials that target CHIP are already registered.

Giant cell arteritis: reviewing the advancing diagnostics and management

Giant Cell Arteritis (GCA) is well known to be a critical ischaemic disease that requires immediate medical recognition to initiate treatment and where one in five people still suffer visual loss. The immunopathophysiology has continued to be characterised, and the influencing of ageing in the development of GCA is beginning to be understood. Recent national and international guidelines have supported the directed use of cranial ultrasound to reduce diagnostic delay and improve clinical outcomes. Immediate high dose glucocorticoids remain the standard emergency treatment for GCA, with a number of targeted agents that have been shown in clinical trials to have superior clinical efficacy and steroid sparing effects. The aim of this review was to present the latest advances in GCA that have the potential to influence routine clinical practice.

PU.1 is required to restrain myelopoiesis during chronic inflammatory stress

Chronic inflammation is a common feature of aging and numerous diseases such as diabetes, obesity, and autoimmune syndromes and has been linked to the development of hematological malignancy. Blood-forming hematopoietic stem cells (HSC) can contribute to these diseases via the production of tissue-damaging myeloid cells and/or the acquisition of mutations in epigenetic and transcriptional regulators that initiate evolution toward leukemogenesis. We previously showed that the myeloid "master regulator" transcription factor PU.1 is robustly induced in HSC by pro-inflammatory cytokines such as interleukin (IL)-1β and limits their proliferative activity. Here, we used a PU.1-deficient mouse model to investigate the broader role of PU.1 in regulating hematopoietic activity in response to chronic inflammatory challenges. We found that PU.1 is critical in restraining inflammatory myelopoiesis via suppression of cell cycle and self-renewal gene programs in myeloid-biased multipotent progenitor (MPP) cells. Our data show that while PU.1 functions as a key driver of myeloid differentiation, it plays an equally critical role in tailoring hematopoietic responses to inflammatory stimuli while limiting expansion and self-renewal gene expression in MPPs. These data identify PU.1 as a key regulator of "emergency" myelopoiesis relevant to inflammatory disease and leukemogenesis.

The impact of epigenetic modifications on allogeneic hematopoietic stem cell transplantation

The field of epigenetics studies the complex processes that regulate gene expression without altering the DNA sequence itself. It is well established that epigenetic modifications are crucial to cellular homeostasis and differentiation and play a vital role in hematopoiesis and immunity. Epigenetic marks can be mitotically and/or meiotically heritable upon cell division, forming the basis of cellular memory, and have the potential to be reversed between cellular fate transitions. Hence, over the past decade, there has been increasing interest in the role that epigenetic modifications may have on the outcomes of allogeneic hematopoietic transplantation and growing enthusiasm in the therapeutic potential these pathways may hold. In this brief review, we provide a basic overview of the types of epigenetic modifications and their biological functions, summarizing the current literature with a focus on hematopoiesis and immunity specifically in the context of allogeneic hematopoietic stem cell transplantation.

Biomarkers of aging

Aging biomarkers are a combination of biological parameters to (i) assess age-related changes, (ii) track the physiological aging process, and (iii) predict the transition into a pathological status. Although a broad spectrum of aging biomarkers has been developed, their potential uses and limitations remain poorly characterized. An immediate goal of biomarkers is to help us answer the following three fundamental questions in aging research: How old are we? Why do we get old? And how can we age slower? This review aims to address this need. Here, we summarize our current knowledge of biomarkers developed for cellular, organ, and organismal levels of aging, comprising six pillars: physiological characteristics, medical imaging, histological features, cellular alterations, molecular changes, and secretory factors. To fulfill all these requisites, we propose that aging biomarkers should qualify for being specific, systemic, and clinically relevant.

CHIP Happens: Clonal Hematopoiesis of Indeterminate Potential and Its Relationship to Solid Tumors

Clonal hematopoiesis of indeterminate potential (CHIP) is characterized by the expansion of hematopoietic cells harboring leukemia-associated somatic mutations in otherwise healthy people and occurs in at least 10% of adults over 70. It is well established that people with CHIP have increased rates of hematologic malignancy, increased risk of cardiovascular disease, and worse all-cause mortality compared with those without CHIP. Despite recent advancements in understanding CHIP as it relates to these known outcomes, much remains to be learned about the development and role of CHIP in other disease states. Emerging research has identified high rates of CHIP in patients with solid tumors, driven in part by oncologic therapy, and revealed associations between CHIP and differential outcomes in both solid tumors and other diseases. Recent studies have demonstrated that CHIP can contribute to dysregulated inflammatory signaling in multiple contexts, underscoring the importance of interrogating how CHIP might alter tumor immunology. Here, we review the role of CHIP mutations in clonal expansion of hematopoietic cells, explore the relationship between CHIP and solid tumors, and discuss the potential roles of CHIP in inflammation and solid tumor biology.

Defining clonal hematopoiesis of indeterminate potential: evolutionary dynamics and detection under aging and inflammation

Clonal hematopoiesis (CH), in which hematopoietic stem and progenitor cell (HSPC) clones and their progeny expand in the circulating blood cell population, occurs following the acquisition of somatic driver mutations. Individuals diagnosed with clonal hematopoiesis of indeterminate potential (CHIP) carry somatic mutations in hematological malignancy-associated driver genes, historically at or above a variant allele frequency of 2%, but do not exhibit abnormal blood cell counts or any other symptoms of hematologic disease. However, CHIP is associated with moderately increased risk of hematological cancer and a greater likelihood of cardiovascular and pulmonary disease. Recent advances in the resolution of high-throughput sequencing experiments suggest CHIP is much more prevalent in the population than once thought, particularly among those aged 60 and over. Although CHIP does elevate the risk of eventual hematological malignancy, only one in 10 individuals with CHIP will receive such a diagnosis; the problem lies in the continued difficulty in accurately separating the 10% of CHIP patients who are most likely to be in a premalignant state from those who are not, given the heterogeneity of this condition and the etiology of the associated hematological cancers. Concerns over the risk of eventual malignancies must be balanced with growing recognition of CH as a common age-dependent occurrence, and efforts to better characterize and differentiate oncogenic clonal expansion from that which is much more benign. In this review, we discuss evolutionary dynamics of CH and CHIP, the relationship of CH to aging and inflammation, and the role of the epigenome in promoting potentially pathogenic or benign cellular trajectories. We outline molecular mechanisms that may contribute to heterogeneity in the etiology of CHIP and the incidence of malignant disease among individuals. Finally, we discuss epigenetic markers and modifications for CHIP detection and monitoring with the potential for translational applications and clinical utility in the near future.

Clinical, Mutational, and Transcriptomic Characteristics in Elderly Korean Individuals With Clonal Hematopoiesis Driver Mutations

Background

Clonal hematopoiesis of indeterminate potential (CHIP), which is defined as the presence of blood cells originating from somatically mutated hematopoietic stem cells, is common among the elderly and is associated with an increased risk of hematologic malignancies. We investigated the clinical, mutational, and transcriptomic characteristics in elderly Korean individuals with CHIP mutations.

Methods

We investigated CHIP in 90 elderly individuals aged ≥60 years with normal complete blood counts at a tertiary-care hospital in Korea between June 2021 and February 2022. Clinical and laboratory data were prospectively obtained. Targeted next-generation sequencing of 49 myeloid malignancy driver genes and massively parallel RNA sequencing were performed to explore the molecular spectrum and transcriptomic characteristics of CHIP mutations.

Results

We detected 51 mutations in 10 genes in 37 (41%) of the study individuals. CHIP prevalence increased with age. CHIP mutations were observed with high prevalence in DNMT3A (26 individuals) and TET2 (eight individuals) and were also found in various other genes, including KDM6A, SMC3, TP53, BRAF, PPM1D, SRSF2, STAG1, and ZRSR2. Baseline characteristics, including age, confounding diseases, and blood cell parameters, showed no significant differences. Using mRNA sequencing, we characterized the altered gene expression profile, implicating neutrophil degranulation and innate immune system dysregulation.

Conclusions

Somatic CHIP driver mutations are common among the elderly in Korea and are detected in various genes, including DNMT3A and TET2. Our study highlights that chronic dysregulation of innate immune signaling is associated with the pathogenesis of various diseases, including hematologic malignancies.

Genomic Landscape of Patients with Germline RUNX1 Variants and Familial Platelet Disorder with Myeloid Malignancy

Germline RUNX1 mutations lead to familial platelet disorder with associated myeloid malignancies (FPDMM), which is characterized by thrombocytopenia and a life-long risk (35-45%) of hematological malignancies. We recently launched a longitudinal natural history study for patients with FPDMM at the NIH Clinical Center. Among 29 families with research genomic data, 28 different germline RUNX1 variants were detected. Besides missense mutations enriched in Runt homology domain and loss-of-function mutations distributed throughout the gene, splice-region mutations and large deletions were detected in 6 and 7 families, respectively. In 24 of 54 (44.4%) non-malignant patients, somatic mutations were detected in at least one of the clonal hematopoiesis of indeterminate potential (CHIP) genes or acute myeloid leukemia (AML) driver genes. BCOR was the most frequently mutated gene (in 9 patients), and multiple BCOR mutations were identified in 4 patients. Mutations in 7 other CHIP or AML driver genes ( DNMT3A, TET2, NRAS, SETBP1, SF3B1, KMT2C , and LRP1B ) were also found in more than one non-malignant patient. Moreover, three unrelated patients (one with myeloid malignancy) carried somatic mutations in NFE2 , which regulates erythroid and megakaryocytic differentiation. Sequential sequencing data from 19 patients demonstrated dynamic changes of somatic mutations over time, and stable clones were more frequently found in elderly patients. In summary, there are diverse types of germline RUNX1 mutations and high frequency of somatic mutations related to clonal hematopoiesis in patients with FPDMM. Monitoring dynamic changes of somatic mutations prospectively will benefit patients’ clinical management and reveal mechanisms for progression to myeloid malignancies.

Key Points

Comprehensive genomic profile of patients with FPDMM with germline RUNX1 mutations. Rising clonal hematopoiesis related secondary mutations that may lead to myeloid malignancies.

Frequent somatic mosaicism in T lymphocyte subsets in individuals with and without multiple sclerosis

Background

Somatic variants are variations in an individual's genome acquired after the zygotic stadium and result from mitotic errors or not (fully) repaired DNA damage.

Objectives

To investigate whether somatic mosaicism in T lymphocyte subsets is enriched early in multiple sclerosis (MS).

Methods

We identified somatic variants with variant allele fractions ≥1% across the whole exome in CD4⁺ and CD8⁺ T lymphocytes of 21 treatment-naive MS patients with <5 years of disease duration and 16 partially age-matched healthy controls. We investigated the known somatic STAT3 variant p.Y640F in peripheral blood in a larger cohort of 446 MS patients and 259 controls.

Results

All subjects carried 1-142 variants in CD4⁺ or CD8⁺ T lymphocytes. Variants were more common, more abundant, and increased with age in CD8⁺ T lymphocytes. Somatic variants were common in the genes DNMT3A and especially STAT3. Overall, the presence or abundance of somatic variants, including the STAT3 p.Y640F variant, did not differ between MS patients and controls.

Conclusions

Somatic variation in T lymphocyte subsets is widespread in both control individuals and MS patients. Somatic mosaicism in T lymphocyte subsets is not enriched in early MS and thus unlikely to contribute to MS risk, but future research needs to address whether a subset of variants influences disease susceptibility.

Multiple myeloma, a quintessential malignant disease of aging: a geroscience perspective on pathogenesis and treatment

Multiple myeloma (MM) is an incurable plasma cell malignancy, which is predominantly a disease of older adults (the median age at diagnosis is 70 years). The slow progression from asymptomatic stages and the late-onset of MM suggest fundamental differences compared to many other hematopoietic system-related malignancies. The concept discussed in this review is that age-related changes at the level of terminally differentiated plasma cells act as the main risk factors for the development of MM. Epigenetic and genetic changes that characterize both MM development and normal aging are highlighted. The relationships between cellular aging processes, genetic mosaicism in plasma cells, and risk for MM and the stochastic processes contributing to clonal selection and expansion of mutated plasma cells are investigated. In line with the DNA damage accumulation theory of aging, in this review, the evolution of monoclonal gammopathy to symptomatic MM is considered. Therapeutic consequences of age-dependent comorbidities that lead to frailty and have fundamental influence on treatment outcome are described. The importance of considering geriatric states when planning the life-long treatment course of an elderly MM patient in order to achieve maximal therapeutic benefit is emphasized.

Navigating the contested borders between myelodysplastic syndrome and acute myeloid leukemia

Myelodysplastic syndrome and acute myeloid leukemia are heterogeneous myeloid neoplasms which arise from the accumulation of mutations in a myeloid stem cell or progenitor that confer survival or growth advantages. These disease processes are formally differentiated by clinical, laboratory, and morphological presentations, especially with regard to the preponderance of blasts in the peripheral blood or bone marrow (AML); however, they are closely associated through their shared lineage as well as their existence on a spectrum with some cases of MDS displaying increased blasts, a feature that reflects more AML-like behavior, and the propensity for MDS to transform into AML. It is increasingly recognized that the distinctions between these two entities result from the divergent patterns of genetic alterations that drive each of them. Mutations in genes related to chromatin-remodeling and the spliceosome are seen in both MDS and AML arising out of antecedent MDS, while mutations in genes related to signaling pathways such as RAS or FLT3 are more typically seen in AML or otherwise are a harbinger of transformation. In this review, we focus on the insights into the biological and genetic distinctions and similarities between MDS and AML that are now used to refine clinical prognostication, guide disease management, and to inform development of novel therapeutic approaches.

The Impact of Inflammation-Induced Tumor Plasticity during Myeloid Transformation

Clonal hematopoiesis (CH) is an aging-associated condition characterized by the clonal outgrowth of mutated preleukemic cells. Individuals with CH are at an increased risk of developing hematopoietic malignancies. Here, we describe a novel animal model carrying a recurrent TET2 missense mutation frequently found in patients with CH and leukemia. In a fashion similar to CH, animals show signs of disease late in life when they develop a wide range of myeloid neoplasms, including acute myeloid leukemia (AML). Using single-cell transcriptomic profiling of the bone marrow, we show that disease progression in aged animals correlates with an enhanced inflammatory response and the emergence of an aberrant inflammatory monocytic cell population. The gene signature characteristic of this inflammatory population is associated with poor prognosis in patients with AML. Our study illustrates an example of collaboration between a genetic lesion found in CH and inflammation, leading to transformation and the establishment of blood neoplasms.

SIGNIFICANCE

Progression from a preleukemic state to transformation, in the presence of TET2 mutations, is coupled with the emergence of inflammation and a novel population of inflammatory monocytes. Genes characteristic of this inflammatory population are associated with the worst prognosis in patients with AML. These studies connect inflammation to progression to leukemia. See related commentary by Pietras and DeGregori, p. 2234 . This article is highlighted in the In This Issue feature, p. 2221.

Current Clinical Practice of Precision Medicine Using Comprehensive Genomic Profiling Tests in Biliary Tract Cancer in Japan

With the recent advances of next generation sequencing technologies, comprehensive genomic profiling (CGP) tests, which are designed to measure more than hundreds of cancer-related genes at a time, have now been widely introduced into daily clinical practice. For the patients whose tumor samples are not fit for tissue-based CGP tests, a blood-based CGP test (liquid biopsy) is available as an alternative option. Three CGP tests, "OncoGuide NCC™Oncopanel System (124 genes)", "FoundationOne®CDx (324 genes)", and "Founda-tionOne®CDx Liquid (324 genes)", are now reimbursed by public insurance in 233 hospitals designated for cancer genomic medicine in Japan. In biliary tract cancer, the prevalence of druggable variants is relatively higher compared to other cancer types and the European Society for Medical Oncology recommends routine use of CGP tests for advanced biliary tract cancer to guide treatment options. The latest National Cancer Center Network guideline lists eight druggable markers (NTRK fusion, MSI-H, TMB-H, BRAF V600E, FGFR2 fusions/rearrangement, IDH1 mutations, RET fusion, and HER2 overexpression) and matched therapies. In Japan, matched therapies for four markers (NTRK, MSI-H, TMB-H, and FGFR2) are reimbursed by public insurance (as of September 2022). The progress of genomic profiling technology will contribute to the improvement of the dismal clinical outcomes of this disease in the future.

Non-neutral clonal selection and its potential role in mammalian germline stem cell dysfunction with advancing age

The concept of natural selection, or "survival of the fittest", refers to an evolutionary process in nature whereby traits emerge in individuals of a population through random gene alterations that enable those individuals to better adapt to changing environmental conditions. This genetic variance allows certain members of the population to gain an advantage over others in the same population to survive and reproduce in greater numbers under new environmental pressures, with the perpetuation of those advantageous traits in future progeny. Here we present that the behavior of adult stem cells in a tissue over time can, in many respects, be viewed in the same manner as evolution, with each stem cell clone being representative of an individual within a population. As stem cells divide or are subjected to cumulative oxidative damage over the lifespan of the organism, random genetic alterations are introduced into each clone that create variance in the population. These changes may occur in parallel to, or in response to, aging-associated changes in microenvironmental cues perceived by the stem cell population. While many of these alterations will be neutral or silent in terms of affecting cell function, a small fraction of these changes will enable certain clones to respond differently to shifts in microenvironmental conditions that arise with advancing age. In some cases, the same advantageous genetic changes that support survival and expansion of certain clones over others in the population (viz. non-neutral competition) could be detrimental to the downstream function of the differentiated stem cell descendants. In the context of the germline, such a situation would be devastating to successful propagation of the species across generations. However, even within a single generation, the “evolution” of stem cell lineages in the body over time can manifest into aging-related organ dysfunction and failure, as well as lead to chronic inflammation, hyperplasia, and cancer. Increased research efforts to evaluate stem cells within a population as individual entities will improve our understanding of how organisms age and how certain diseases develop, which in turn may open new opportunities for clinical detection and management of diverse pathologies.

Molecular Pathways in Clonal Hematopoiesis: From the Acquisition of Somatic Mutations to Transformation into Hematologic Neoplasm

Hematopoietic stem cell aging, through the acquisition of somatic mutations, gives rise to clonal hematopoiesis (CH). While a high prevalence of CH has been described in otherwise healthy older adults, CH confers an increased risk of both hematologic and non-hematologic diseases. Classification of CH into clonal hematopoiesis of indeterminate potential (CHIP) and clonal cytopenia of undetermined significance (CCUS) further describes this neoplastic myeloid precursor state and stratifies individuals at risk of developing clinically significant complications. The sequential acquisition of driver mutations, such as DNMT3A, TET2, and ASXL1, provide a selective advantage and lead to clonal expansion. Inflammation, microbiome signatures, and external selective pressures also contribute to clonal evolution. Despite significant progress in recent years, the precise molecular mechanisms driving CH transformation to hematologic neoplasms are not well defined. Further understanding of these complex mechanisms may improve risk stratification and introduce therapeutic interventions in CH. Here we discuss the genetic drivers underpinning CH, mechanisms for clonal evolution, and transformation to hematologic neoplasm.

Clinical Significance of Clonal Hematopoiesis of Indeterminate Potential in Hematology and Cardiovascular Disease

Liquid profiling uses circulating tumor DNA (ctDNA) for minimal invasive tumor mutational profiling from peripheral blood. The presence of somatic mutations in peripheral blood cells without further evidence of a hematologic neoplasm defines clonal hematopoiesis of indeterminate potential (CHIP). CHIP-mutations can be found in the cell-free DNA (cfDNA) of plasma, are a potential cause of false positive results in liquid profiling, and thus limit its usage in screening settings. Various strategies are in place to mitigate the effect of CHIP on the performance of ctDNA assays, but the detection of CHIP also represents a clinically significant incidental finding. The sequelae of CHIP comprise the risk of progression to a hematologic neoplasm including therapy-related myeloid neoplasms. While the hematological risk increases with the co-occurrence of unexplained blood count abnormalities, a number of non-hematologic diseases have independently been associated with CHIP. In particular, CHIP represents a major risk factor for cardiovascular disease such as atherosclerosis or heart failure. The management of CHIP requires an interdisciplinary setting and represents a new topic in the field of cardio-oncology. In the future, the information on CHIP may be taken into account for personalized therapy of cancer patients.

A case of refractory systemic lupus erythematosus with monocytosis exhibiting somatic KRAS mutation

Background

Systemic lupus erythematosus (SLE), an autoimmune disorder that damages various organ systems, is caused by a combination of genetic and environmental factors. Although germline mutations of several genes are known to cause juvenile SLE, most of the susceptibility genetic variants of adult SLE are common variants of the population, somatic mutations that cause or exacerbate SLE have not been reported. We hereby report a refractory SLE case with monocytosis accompanying somatic KRAS mutation that have been shown to cause lupus-like symptoms.

Case presentation

A 60-year-old female patient who had been diagnosed with SLE was admitted to our hospital. Although prednisolone and tacrolimus treatments had kept her thrombocytopenia and anti-DNA Ab level at bay for more than 4 years, a diagnosis of transverse myelitis was made when she became acutely ill with pleocytosis. Elevated cells (predominately monocytes), protein, IgG, and IL-6 levels were also found in the cerebrospinal fluid (CSF) of the patient. Standard pulse treatments of methylprednisolone, high-dose of prednisolone, and intravenous cyclophosphamide in combination with plasma exchange could not alleviate the refractory neural and autoimmune manifestation. Monocytosis of peripheral blood was also noted. Flow cytometric analysis revealed elevated ratio of CD14+CD16+ atypical monocytes, which excluded the possibility of chronic myelomonocytic leukemia. Lupus-like symptoms with monocytosis reminded us of Ras-associated autoimmune leukoproliferative disorder, and Sanger sequencing of KRAS and NRAS genes from the patients’ peripheral blood mononuclear cells (PBMC), sorted CD3+ lymphocytes and CD14+ monocytes, and cerebrospinal fluid were performed. An activating KRAS somatic mutation was found in the patients’ DNA at the time of encephalomyelitis diagnosis.

Conclusion

Somatic mutations of some genes including KRAS may cause the refractoriness of SLE.