Search Results (62)

Clonal hematopoiesis refers to the clonal expansion of hematopoietic stem and progenitor cells, driven by somatic mutations. Major mutated genes in clonal hematopoiesis include genes involved in epigenetic regulation including DNA methylation and/or chromatin modification (e.g., DNMT3A, TET2, and ASXL1), tumor suppressors (e.g., TP53), signal transduction (e.g., JAK2), and RNA splicing (e.g., SF3B1 and SRSF2). Clonal hematopoiesis includes clonal hematopoiesis of indeterminate potential (CHIP), clonal cytopenia of unknown significance (CCUS), and myelodysplastic syndromes/neoplasms (MDS). CHIP occurs when the frequency of the variant allele equals or exceeds 2% (4% for X-linked genes in males) in the absence of cytopenias. CHIP is common among older persons and is associated with an increased risk of hematologic cancer. CHIP is also associated with an increased risk of atherosclerotic disease including acute myocardial infarction, stroke, cardiac failure, and abdominal aneurysm. Increasing evidence suggests that CHIP is associated with venous thromboembolic disease. Somatic mutations lead to proliferation of hematopoietic progenitor cells and their progeny, resulting in excessive activation of granulocytes and monocytes. It could be postulated that chronic inflammation caused by clonal expansion of myeloid cells carrying mutations in DNMT3A, TET2, and ASXL1 (“DTA”) genes may constitute an independent risk factor in clot formation and endothelial-cell damage. DTA mutations correlate with elevated proinflammatory cytokines such as IL-1β and IL-6 and enhanced activation of inflammasomes. Moreover, JAK2 mutations may have a direct role in the activation of platelets and coagulation. In vivo murine studies have demonstrated that activation of the JAK-STAT signaling pathway promotes neutrophil extracellular trap (NET) formation, contributing to a prothrombotic state. Insights from related clonal disorders such as paroxysmal nocturnal hemoglobinuria and the VEXAS syndrome support the concept that mutation-driven innate immune activation can directly perturb hemostatic balance. This review aims to summarize the association between clonal expansion of hematopoietic cells and thrombotic disease, and highlight how somatic mutations in hematopoietic cells may contribute to vascular disease and thrombogenesis. Full article

Background/Objectives: The increasing sensitivity of molecular diagnostic techniques has led to the frequent detection of low-level JAK2 V617F mutations in individuals without overt myeloproliferative neoplasms (MPNs), creating uncertainty regarding their biological and clinical significance. This study aimed to evaluate the clinical relevance, thrombotic risk, and hematologic evolution associated with low JAK2 V617F allele burden. Methods: We conducted a retrospective single-center study including adult patients tested for JAK2 V617F between January 2016 and December 2023. Patients with a variant allele frequency (VAF) <2% who did not meet WHO or 2022 International Consensus Classification diagnostic criteria for MPN at baseline were included. Clinical characteristics, laboratory parameters, molecular findings, thrombotic events, and longitudinal ou--comes were analyzed. Results: Among two-thousand-three-hundred-seventy-two tested subjects, 55 patients (9.2% of JAK2-positive cases) harbored a low-level JAK2 V617F mutation (median VAF 0.35%). Over a median follow-up of 31.7 months, 12 patients (21.8%) progressed to overt MPN. Baseline VAF was significantly higher in patients who evolved to MPN compared to non-progressors. Thrombotic events occurred in 30.9% of patients and were associated with higher VAF values irrespective of MPN diagnosis. Serial molecular analyses showed stable persistence of the mutant clone over time. Conclusions: Low-burden JAK2 V617F mutations represent clinically relevant clonal events associated with thrombotic risk and potential disease evolution. These findings support the need for structured clinical and molecular follow-up even in the absence of initial diagnostic criteria. Full article

Clonal hematopoiesis (CH) is the expansion of clones from a single hematopoietic stem cell (HSC) in the bone marrow. Clonal hematopoiesis of indeterminate potential (CHIP) refers to CH defined by the presence of pre-leukemic driver mutations in at least 2% of alleles in sequenced peripheral blood. This phenomenon is, by definition, associated not only with the future development of acute myeloid leukemia but also with non-malignant conditions, including cardiovascular disease. However, the underlying molecular mechanisms for CH in non-malignant diseases, such as cardiovascular disease, are not fully explained. Certain subtypes of CHIP may give rise to proinflammatory immune cells, which, in turn, may promote atherosclerosis progression. Key subtypes of CHIP include mutations in genes encoding epigenetic regulators DNMT3A (DNA methyltransferase 3A), TET2 (ten-eleven translocation methylcytosine dioxygenase 2), and ASXL1 (associated sex combs-like 1), as well as mutations in the gene encoding hematopoietic cytokine signaling: JAK2 (Janus kinase 2). The aim of this review is to summarize the current knowledge of CHIP and its association with inflammation and cardiovascular risk factors. Full article

Adipocytes produce the hormone leptin, a hormone that links energy availability to reproductive function by permitting activation of the hypothalamic–pituitary–gonadal (HPG) axis. Loss-of-function mutations in the long leptin receptor isoform (LEPRb) disrupt intracellular signaling pathways, including the Janus kinase 2 (JAK2)/signal transducer and activator of transcription 3 (STAT3), phosphoinositide 3-kinase (PI3K), and mitogen-activated protein kinase (MAPK) pathways, resulting in central leptin resistance and impaired neuroendocrine control of reproduction. Evidence from human monogenic obesity syndromes, animal models, and neuroendocrine studies indicates that LEPRb mutations disrupt hypothalamic circuitry upstream of gonadotropin-releasing hormone (GnRH) neurons, impairing GnRH pulsatility and leading to hypogonadotropic hypogonadism (HH) and infertility. This review synthesizes molecular, translational, and clinical data highlighting the central role of kisspeptin-mediated signaling in leptin-dependent reproductive regulation. Current therapeutic limitations are discussed alongside emerging approaches, including kisspeptin-based therapies and receptor-targeted strategies. Elucidating how LEPRb dysfunction disrupts metabolic–reproductive integration may provide insights into both rare monogenic conditions and common obesity-associated reproductive dysfunction. Full article

Clonal hematopoiesis of indeterminate potential (CHIP) is defined by the expansion of hematopoietic stem cells harboring leukemogenic mutations in the absence of overt malignancy. Strongly associated with advancing age, CHIP is detected by next-generation sequencing of peripheral blood in more than 20% of individuals over 80, most commonly through mutations in DNMT3A, TET2, ASXL1, and PPM1D. While CHIP confers over a four-fold increased risk of hematologic malignancy, it has recently emerged as a key determinant of cardiometabolic health. Epidemiological data indicated a 40% higher cardiovascular disease (CVD) risk events and a 34% increase in all-cause mortality among CHIP carriers, with specific mutations and larger clone sizes conferring greater cardiovascular burden. Preclinical studies have shown that macrophages deficient in TET2 or DNMT3A drive interleukin (IL)-1β/IL-6 inflammasome activation, thereby promoting atherosclerosis and metabolic dysfunction, whereas the JAK2V617F mutation accelerates thrombosis. CHIP integrates into a broader network of dysregulation encompassing adiposity and inflammaging, which underlies its association with diverse comorbidities, including type 2 diabetes (T2D), chronic kidney disease (CKD), and chronic obstructive pulmonary disease (COPD). Multi-omics approaches have identified epigenetic and proteomic signatures correlated with CHIP expansion, providing potential biomarkers for risk stratification. Despite growing evidence of its systemic impact, CHIP screening remains limited to research settings. Emerging therapeutic strategies, including inflammasome inhibition, STING modulation, and epigenetic restoration, highlight its potential as a modifiable risk factor. This narrative review synthesizes current epidemiological, mechanistic, and translational insights, framing CHIP as an emerging causal factor in cardiometabolic disease and as a promising target for precision medicine in aging populations. Full article

Myeloproliferative neoplasms (MPNs) are clonal hematopoietic disorders characterized by the abnormal proliferation of myeloid cells. In addition to the main driver mutations in JAK2, MPL, and CALR, the transcription factor nuclear factor erythroid 2 (NFE2) has emerged as a key contributor to MPN pathophysiology. NFE2 expression is elevated in the majority of MPN patients, and augmented NFE2 activity in hematopoietic stem cells is sufficient to induce an MPN phenotype with spontaneous leukemic transformation in murine models. Moreover, NFE2 mutations, found in a subset of MPN patients, augment NFE2 activity and are associated with a markedly increased risk of progression to acute myeloid leukemia (AML). However, the molecular mechanism by which NFE2 mutations cause leukemogenesis is not understood. Here, we demonstrate that the E3 ubiquitin ligase ITCH mediates proteasomal degradation of wild-type (wt) NFE2 in HEK-293T cells. A gain-of-function truncation mutant, NFE2-226aa, retains the capacity to interact with ITCH but is no longer degraded. Rather, NFE2-226aa protects wt NFE2 from ITCH-dependent degradation, resulting in enhanced NFE2 activity. Full article

Inflammatory bowel disease (IBD) is a chronic immune-mediated condition of the gastrointestinal tract, characterized by dysregulated inflammatory responses throughout the gastrointestinal tract. It includes two major phenotypes, Crohn’s disease (CD) and ulcerative colitis (UC), which present with varying gastrointestinal and systemic symptoms. The pathophysiology of IBD is multifactorial including genetic predisposition, mucosal and epithelial dysfunction, environmental injury, and both innate and adaptive immune response abnormalities. Several predisposing genetic factors have been associated with IBD explaining the strong hereditary risk for both CD and UC. For example, Caspase Recruitment Domain 9 (CARD9) variant rs10781499 increases risk for IBD, while other variants are specific to either CD or UC. CD is related to loss-of-function mutations in the nucleotide oligomerization domain containing the protein 2 (NOD2) gene and Autophagy-Related 16-like 1 (ATG16L1) gene. UC risk is increased particularly in Chinese populations by the A-1661G polymorphism of the Cytotoxic T-lymphocyte antigen 4 (CTLA-4) gene. This abnormal CTLA-4 interferes with B- and T-cell responses causing predisposition to autoimmune conditions. Previous studies suggested that IBD results from breakdown of the adaptive immune system, primarily of T-cells. However, new evidence suggests that a primary breakdown of the innate immune system in both CD and UC increases susceptibility to invasion by viruses and bacteria, with a compensatory overactivation of the adaptive immune system as a result. When this viral and microbial invasion continues, further damage is incurred, resulting in a downward cycle of further cytokine activation and epithelial damage. Released biomarkers also affect the permeability of the epithelial membrane, including lactoferrin, nitric oxide (NO), myeloperoxidase (MPO) and its activation of hypochlorous acid, matrix metalloproteinases (MMPs), especially MMP-9, omentin-1, and others. Increased macrophage and dendritic cell dysfunction, increased neutrophil activity, increased numbers of innate lymphoid cells, increased T-cells with decreased regulatory T-cells (Tregs), and changes in B-cell populations and immunoglobulin (Ig) functions are all associated with IBD. Finally, treatment of IBD has typically consisted of medical management (e.g., aminosalicylates and corticosteroids) and lifestyle modification, and surgical intervention in extreme cases. New classes of medications with more favorable side effect profiles include anti-integrin antibodies, vedolizumab, etrolizumab, and carotegrast methyl. Additionally, fecal microbiota transplant (FMT) is a newer area of research for treatment of IBD along with TNF-blockers, JAK inhibitors, and S1PR modulators. However, expense and long preparation time have limited the usefulness of FMT. Full article

The use of JAK inhibitors (JAKi) represents a promising therapeutic approach for patients with lymphoid leukemias (Lym-L). Clinical trials are ongoing to evaluate the safety and efficacy of JAK inhibitors. Over the last years, there have been reports of preclinical Lym-L models that developed JAKi resistance, and reports of patients treated with JAKi who experienced treatment failure. Although evidence shows that there are diverse JAKi mechanisms, no review studies have been performed that summarize and discuss this information. This scoping review aimed to provide an updated overview of the mechanisms underlying JAKi molecular resistance in Lym-L. According to a scoping review PRISMA guidelines, a search was conducted in the PubMed and Europe PMC databases for studies published from 2010 to 2024. We included articles that described the molecular resistance to JAKi in Lym-L preclinical models or patients. The search was complemented by a review of laboratory-engineered resistant mutations in genomic datasets to obtain more information about their presence in patients with Lym-L. Twenty-two articles were eligible for this review, and six different mechanisms of molecular resistance were identified: (1) point mutations in the kinase domain, (2) cooperation between double-JAK mutants, (3) inactivation of phosphatases, (4) evasion of JAK inhibition due to trans-phosphorylation of JAK family proteins, (5) upregulation of pro-survival proteins, and (6) activation of kinase cross-signaling pathways. The integrated evidence enabled the identification of specific mechanisms of molecular resistance to JAKi in Lym-L, as well as promising therapeutic approaches to prevent them. These include selecting a sensitive JAKi, choosing an effective dosage regimen, and combining inhibitory molecules. Full article

The JAK2V617F mutation is a major molecular factor in Philadelphia chromosome-negative myeloproliferative neoplasms (MPNs) and has been increasingly associated with clonal progression to acute myeloid leukemia (AML), resulting in a poorer prognosis and resistance to conventional therapies. This study integrates a comprehensive literature review with bioinformatic approaches to investigate the potential inhibitory activity of Epigallocatechin Gallate (EGCG), a green tea polyphenol widely recognized for its antioxidant and anticancer properties, on the JAK2V617F mutation. Clinical data from case reports demonstrated heterogeneity in disease progression and frequent therapeutic failures. Molecular docking analysis using the Janus Kinase 2 (JAK2) protein structure (PDB ID: 6D2I) identified a high-affinity binding pocket for EGCG near the V617F mutation site. EGCG exhibited strong binding affinity (−9.2 kcal/mol), forming key interactions with residues Lys581, Ile559, and Leu680, suggesting allosteric modulation of the JH2 pseudokinase domain. To validate our docking protocol, redocking of the known inhibitor AT9283 yielded a favorable Root Mean Square Deviation (RMSD) 2.683 Å and binding energy (−8.3 kcal/mol), confirming the reliability of our approach. Notably, EGCG demonstrated superior binding affinity compared to AT9283 and targets a distinct allosteric site, highlighting its unique mechanism of action and potential as a selective allosteric inhibitor. These findings position EGCG as a promising candidate for future preclinical evaluation, offering a novel strategy to overcome therapy resistance in JAK2V617F-driven malignancies. Full article

Background: Acute lymphoblastic leukemia (ALL) is the most common pediatric malignancy, with cure rates exceeding 80% due to advancements in treatment protocols and supportive care. However, in children with Down syndrome (DS), ALL (DS-ALL) presents distinct genomic and clinical challenges. These include mutations in Janus kinase 2 (JAK2), neuroblastoma RAS viral oncogene homolog (NRAS), and E1A-binding protein p300 (EP300), as well as cytokine receptor-like factor 2 (CRLF2) rearrangements—such as P2RY8-CRLF2 fusion—and intrachromosomal amplification of chromosome 21 (iAMP21). These aberrations are associated with poor prognosis and increased risk of relapse. The objective of this study was to present a unique DS-ALL case with five concurrent high-risk genomic lesions and to contextualize its management in light of existing literature, emphasizing minimal residual disease (MRD)-guided therapy and supportive care. Case Report and Results: We present the case of a three-year-old boy with DS and B-cell ALL (B-ALL), in whom multiple high-risk genomic features co-occurred. Despite these adverse prognostic markers, the patient achieved complete remission following an intensive high-dose induction protocol. We also discuss therapeutic strategies that aim at balancing individualized treatment approaches with optimized supportive care to reduce toxicity and minimize relapse risk. Conclusions: This case underlines the importance of comprehensive molecular diagnostics, serial MRD monitoring, and personalized multidisciplinary care in DS-ALL. Full article

Background: Genetic alterations in CSF3R, typically associated with chronic neutrophilic leukemia (CNL) and atypical chronic myeloid leukemia (aCML), rarely occur in other myeloid neoplasms. Methods: This study characterized the clinical, morphologic, cytogenetic, and molecular features of 13 patients with non-CNL non-aCML myeloid neoplasms with CSF3R alterations. Patients (median age, 77 years) were categorized into groups with a myelodysplastic/myeloproliferative neoplasm (MDS/MPN) (n = 5), acute leukemia (n = 4), and other myeloid neoplasms (n = 4) based on the WHO 2022 and ICC criteria. Results: The CSF3R p.Thr618Ile mutation was most frequent (11/13), with additional pathogenic variants including p.Gln743Ter and frameshift mutations affecting the cytoplasmic tail. Variant allele frequencies (VAFs) ranged from 2% to 49%, with the highest median VAF in the MDS/MPN group. Co-mutations varied by subtype; MDS/MPN, NOS, and CMML cases frequently harbored mutations in epigenetic regulators (ASXL1, TET2) and splicing factors (SF3B1, SRSF2, ZRSR2), while acute leukemia cases showed alterations in JAK3, STAT3, and NRAS. Survival analysis revealed distinct patterns across the three diagnostic groups, with MDS/MPN having the poorest prognosis. Conclusion: This study expands the recognized spectrum of CSF3R-related myeloid neoplasms and highlights the clinical and molecular heterogeneity associated with these mutations, emphasizing the need for comprehensive molecular profiling and the potential for targeted therapies. Full article

Background and Objectives: Philadelphia (Ph)-negative myeloproliferative neoplasms can exhibit defects in Janus kinase 2 (JAK2), Calreticulin (CalR), and MPL genes. It is possible that the presence of other driver mutations may influence diagnosis and prognosis in patients who do not have a JAK2 gene mutation. The purpose of this study was to assess the frequency of CalR and MPL gene mutations and the clinical effects of these mutations in JAK2 gene-unmutated MPN patients from a single center. Materials and Methods: We examined 46 patients (ET/PMF: 34/12) diagnosed with MPNs regarding their genetic conditions, diagnoses, and complications. Results: CalR Type 1 gene mutation was detected in 26.1% of cases, CalR Type 2 gene mutation in 13.0%, MPL-L gene mutation in 2.2%, and MPL-K gene mutation in 6.5%. In total, 56.5% of patients were triple-negative. The presence of CalR Type 1 and Type 2 mutations was significantly more prevalent in patients with essential thrombocytosis (ET), although the difference did not reach statistical significance (p = 0.51, p = 0.57). In contrast, MPL mutations were only observed in patients with primary myelofibrosis (PMF). Conclusions: We found no correlation between thrombosis, leukemic transformation, and driver mutations. MPL gene mutation was present in only myelofibrosis patients, and CALR gene mutation was present in one of the three cases of leukemic transformation. The triple-negative group had a lower survival rate, but this difference was not statistically significant (110.3 months vs. 121.4 months, respectively, p = 0.53). However, the sample size was quite small. Our limited observations suggest a possible trend that requires confirmation. Full article

The Janus kinase 2 (JAK2) protein fulfills an important role in hematopoiesis via the Janus kinase/signal transducer and activator of transcription (JAK/STAT) pathway, as it provides the genetic driver of BCR::ABL1-negative myeloproliferative neoplasms (MPNs), which are clinically manifested as polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (PMF). The most common cause of MPNs is the mutation of JAK2 V617F in the JAK2 gene, which results in increased cell proliferation. However, both the pathogenesis and treatment regimen of BCR::ABL1-negative MPNs remain poorly understood. The aim of the present study was to establish K562 cell lines with a point mutation in exon 14 (JAK2p.V617F) using CRISPR/Cas9 technology. The modified JAK2 V617F cell lines were examined for the gene mutation using droplet digital PCR (DDPCR), and the presence of the mutation was confirmed by DNA sequencing. Modified cells were characterized by measuring JAK2 gene expression and the extent of cell proliferation. Interferon α2a (IFN-α2a) and arsenic trioxide were also administered to the cells to explore their potential effects. The JAK2 V617F-mutated cells were found to exhibit a higher level of JAK2 gene expression compared with the wild type. Interestingly, a significant increase in the proliferation rate was observed with the modified cells compared with the wild type cells (p < 0.001), as assessed from the JAK2 gene expression levels. Furthermore, the treatments with IFN-α2a and arsenic trioxide led to the preferential suppression of the cell proliferation rate of the K562 expressing mutant JAK2 cells compared with the wild type cells, and this suppression occurred in a dose-dependent manner(p < 0.01). Moreover, the modified cells were able to differentiate into megakaryocyte-like cells following stimulation with phorbol 12 myristate 13 acetate (PMA). Taken together, the results of the present study have shown that the CRISPR/Cas9-modified JAK2 V617F model may be used as a disease model in the search of novel therapies for MPNs. Full article

Clear-cell renal cell carcinoma (ccRCC) is associated with the mutated von Hippel–Lindau (VHL) gene leading to the activation of hypoxia-inducible factor 1A (HIF1A) and subsequent overexpression of erythropoietin (EPO). We analyzed tumor and healthy tissues from 43 ccRCC patients after radical nephrectomy and cultured 786-O (biallelic VHL inactivation) and Caki-1 (wild-type VHL) cells in normal (21% O₂) and low oxygen (3% O₂) with 10% and 2% fetal bovine serum (FBS). DNA sequencing, including Sanger sequencing, MLPA and LOH, revealed 27 somatic mutations of VHL in ccRCC. HIF1A protein showed decreased or no expression in tumors compared to healthy tissue, independent of VHL alteration. The 786-O cells showed increased HIF1A protein expression after 48 h under low oxygen and 10% FBS. EPO and erythropoietin receptor (EPOR) were significantly decreased in ccRCC without HIF1A expression. EPO mRNA increased in the 786-O cells at 3% O₂ after 48 h, while the Caki-1 cells had low or no EPO expression. Hypoxia increased EPOR mRNA in the Caki-1 cells at 10% FBS, but decreased in the 786-O cells at 2% FBS after 48 h. JAK2/STAT5A activity was increased only in HIF1A-positive tumors. These results suggest that EPO/EPOR activation in ccRCC is mainly driven by low oxygen, not VHL regulation of hypoxia-related responses. Full article

Janus kinase 2 (JAK2) is an important intracellular mediator of cytokine signaling. Mutations in the JAK2 gene are associated with myeloproliferative neoplasms (MPNs) such as polycythemia vera (PV) and essential thrombocythemia (ET), while aberrant JAK2 activity is also associated with a number of immune diseases. The acquired somatic mutation JAK2 V617F (95% of cases of PV and in 55–60% of cases of ET), which constitutively activates the JAK2, is the most common molecular event in MPN. The development of specific JAK2 inhibitors is therefore of considerable clinical importance. Ruxolitinib is a JAK inhibitor recently approved by the FDA/EMA and effective in relieving symptoms in patients with MPN. Ruxolitinib binds to the JAK2 last domain, namely JH1; its action on the dynamics of the domain is still only partially known. Using Molecular Dynamics simulations, we have analyzed the JH1 domain in four different states as follows: (i) alone, (ii) with one phosphorylation, (iii) adding Ruxolitinib, and (iv) with five phosphorylations and Ruxolitinib. The ligand induces a dynamic behavior similar to the inactive form of JH1, with a less flexible state than the phosphorylated active form of JH1. This study highlights the inhibitory effect of Ruxolitinib on the JH1 domain, demonstrating the importance of dynamics in regulating JH1 activation. Full article