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1. Fecal Microbial Community Composition in Myeloproliferative Neoplasm Patients Is Associated with an Inflammatory State

   https://doi.org/10.1128/spectrum.00032-22  

   Oliver, Andrew; El Alaoui, Kenza; Haunschild, Carolyn; Avelar-Barragan, Julio; Mendez Luque, Laura F.; Whiteson, Katrine; Fleischman, Angela G.; Du, Yun; Asangba, Abigail (June 2022, Microbiology Spectrum)

   Claesen, Jan (Ed.)

   ABSTRACT The capacity of the human microbiome to modulate inflammation in the context of cancer is becoming increasingly clear. Myeloproliferative neoplasms (MPNs) are chronic hematologic malignancies in which inflammation plays a key role in disease initiation, progression, and symptomatology. To better understand the composition of the gut microbiome in patients with MPN, triplicate fecal samples were collected from 25 MPN patients and 25 non-MPN controls. Although most of the variance between the microbial community compositions could be attributed to the individual (permutational analysis of variance [PERMANOVA], R 2  = 0.92, P  = 0.001), 1.7% of the variance could be attributed to disease status (MPN versus non-MPN). When a more detailed analysis was performed, significantly fewer reads mapping to a species of Phascolarctobacterium , a microbe previously associated with reduced inflammation, were found in MPNs. Further, our data revealed an association between Parabacteroides and tumor necrosis factor alpha (TNF-α), an inflammatory cytokine elevated in MPNs. Taken together, our results indicate a significant difference in the microbiome of MPN patients compared to non-MPN controls, and we identify specific species which may have a role in the chronic inflammation central to this disease. IMPORTANCE MPNs are chronic blood cancers in which inflammation plays a key role in disease initiation, progression, and symptomatology. The gut microbiome modulates normal blood development and inflammation and may also impact the development and manifestation of blood cancers. Therefore, the microbiome may be an important modulator of inflammation in MPN and could potentially be leveraged therapeutically in this disease. However, the relationship between the gut microbiome and MPNs has not been defined. Therefore, we performed an evaluation of the MPN microbiome, comparing the microbiomes of MPN patients with healthy donors and between MPN patients with various states of disease. 

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2. Effects of calreticulin mutations on cell transformation and immunity

   https://doi.org/10.1111/jcmm.17713  

   Desikan, Harini; Kaur, Amanpreet; Pogozheva, Irina D.; Raghavan, Malini (March 2023, Journal of Cellular and Molecular Medicine)

   Abstract Myeloproliferative neoplasms (MPNs) are cancers involving dysregulated production and function of myeloid lineage hematopoietic cells. Among MPNs, Essential thrombocythemia (ET), Polycythemia Vera (PV) and Myelofibrosis (MF), are driven by mutations that activate the JAK–STAT signalling pathway. Somatic mutations of calreticulin (CRT), an endoplasmic reticulum (ER)‐localized lectin chaperone, are driver mutations in approximately 25% of ET and 35% of MF patients. The MPN‐linked mutant CRT proteins have novel frameshifted carboxy‐domain sequences and lack an ER retention motif, resulting in their secretion. Wild type CRT is a regulator of ER calcium homeostasis and plays a key role in the assembly of major histocompatibility complex (MHC) class I molecules, which are the ligands for antigen receptors of CD8⁺T cells. Mutant CRT‐linked oncogenesis results from the dysregulation of calcium signalling in cells and the formation of stable complexes of mutant CRT with myeloproliferative leukemia (MPL) protein, followed by downstream activation of the JAK–STAT signalling pathway. The intricate participation of CRT in ER protein folding, calcium homeostasis and immunity suggests the involvement of multiple mechanisms of mutant CRT‐linked oncogenesis. In this review, we highlight recent findings related to the role of MPN‐linked CRT mutations in the dysregulation of calcium homeostasis, MPL activation and immunity. 

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3. N-acetylcysteine inhibits thrombosis in a murine model of myeloproliferative neoplasm

   https://doi.org/10.1182/bloodadvances.2019000967  

   Craver, Brianna M.; Ramanathan, Gajalakshmi; Hoang, Summer; Chang, Xinyue; Mendez Luque, Laura F.; Brooks, Stefan; Lai, Hew Yeng; Fleischman, Angela G. (January 2020, Blood Advances)

   null (Ed.)

   Abstract Thrombosis is a major cause of mortality in patients with myeloproliferative neoplasms (MPNs), though there is currently little to offer patients with MPN beyond aspirin and cytoreductive therapies such as hydroxyurea for primary prevention. Thrombogenesis in MPN involves multiple cellular mechanisms, including platelet activation and neutrophil-extracellular trap formation; therefore, an antithrombotic agent that targets one or more of these processes would be of therapeutic benefit in MPN. Here, we treated the JAK2V617F knockin mouse model of polycythemia vera with N-acetylcysteine (NAC), a sulfhydryl-containing compound with broad effects on glutathione replenishment, free radical scavenging, and reducing disulfide bonds, to investigate its antithrombotic effects in the context of MPN. Strikingly, NAC treatment extended the lifespan of JAK2V617F mice without impacting blood counts or splenomegaly. Using an acute pulmonary thrombosis model in vivo, we found that NAC reduced thrombus formation to a similar extent as the irreversible platelet inhibitor aspirin. In vitro analysis of platelet activation revealed that NAC reduced thrombin-induced platelet-leukocyte aggregate formation in JAK2V617F mice. Furthermore, NAC reduced neutrophil extracellular trap formation in primary human neutrophils from patients with MPN as well as healthy controls. These results provide evidence that N-acetylcysteine inhibits thrombosis in JAK2V617F mice and provide a pre-clinical rationale for investigating NAC as a therapeutic to reduce thrombotic risk in MPN. 

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4. A multiscale inflammatory map: linking individual stress to societal dysfunction

   https://doi.org/10.3389/fsci.2023.1239462  

   Vodovotz, Yoram; Arciero, Julia; Verschure, Paul_F_M J; Katz, David L (March 2024, Frontiers in Science)

   As populations worldwide show increasing levels of stress, understanding emerging links among stress, inflammation, cognition, and behavior is vital to human and planetary health. We hypothesize that inflammation is a multiscale driver connecting stressors that affect individuals to large-scale societal dysfunction and, ultimately, to planetary-scale environmental impacts. We propose a “central inflammation map” hypothesis to explain how the brain regulates inflammation and how inflammation impairs cognition, emotion, and action. According to our hypothesis, these interdependent inflammatory and neural processes, and the inter-individual transmission of environmental, infectious, and behavioral stressors—amplified via high-throughput digital global communications—can culminate in a multiscale, runaway, feed-forward process that could detrimentally affect human decision-making and behavior at scale, ultimately impairing the ability to address these same stressors. This perspective could provide non-intuitive explanations for behaviors and relationships among cells, organisms, and communities of organisms, potentially including population-level responses to stressors as diverse as global climate change, conflicts, and the COVID-19 pandemic. To illustrate our hypothesis and elucidate its mechanistic underpinnings, we present a mathematical model applicable to the individual and societal levels to test the links among stress, inflammation, control, and healing, including the implications of transmission, intervention (e.g., via lifestyle modification or medication), and resilience. Future research is needed to validate the model’s assumptions and conclusions against empirical benchmarks and to expand the factors/variables employed. Our model illustrates the need for multilayered, multiscale stress mitigation interventions, including lifestyle measures, precision therapeutics, and human ecosystem design. Our analysis shows the need for a coordinated, interdisciplinary, international research effort to understand the multiscale nature of stress. Doing so would inform the creation of interventions that improve individuals’ lives; enhance communities’ resilience to stress; and mitigate the adverse effects of stress on the world. 

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5. The SMAC mimetic LCL-161 selectively targets JAK2V617F mutant cells

   https://doi.org/10.1186/s40164-019-0157-6  

   Craver, Brianna M.; Nguyen, Thanh Kim; Nguyen, Jenny; Nguyen, Hellen; Huynh, Christy; Morse, Sarah J.; Fleischman, Angela G. (December 2020, Experimental Hematology & Oncology)

   null (Ed.)

   Abstract Background Evasion from programmed cell death is a hallmark of cancer and can be achieved in cancer cells by overexpression of inhibitor of apoptosis proteins (IAPs). Second mitochondria-derived activator of caspases (SMAC) directly bind to IAPs and promote apoptosis; thus, SMAC mimetics have been investigated in a variety of cancer types. particularly in diseases with high inflammation and NFĸB activation. Given that elevated TNFα levels and NFĸB activation is a characteristic feature of myeloproliferative neoplasms (MPN), we investigated the effect of the SMAC mimetic LCL-161 on MPN cell survival in vitro and disease development in vivo. Methods To investigate the effect of the SMAC mimetic LCL-161 in vitro, we utilized murine and human cell lines to perform cell viability assays as well as primary bone marrow from mice or humans with JAK2 V617F –driven MPN to interrogate myeloid colony formation. To elucidate the effect of the SMAC mimetic LCL-161 in vivo, we treated a JAK2 V617F –driven mouse model of MPN with LCL-161 then assessed blood counts, splenomegaly, and myelofibrosis. Results We found that JAK2 V617F -mutated cells are hypersensitive to the SMAC mimetic LCL-161 in the absence of exogenous TNFα. JAK2 kinase activity and NFĸB activation is required for JAK2 V617F -mediated sensitivity to LCL-161, as JAK or NFĸB inhibitors diminished the differential sensitivity of JAK2 V617F mutant cells to IAP inhibition. Finally, LCL-161 reduces splenomegaly and may reduce fibrosis in a mouse model of JAK2 V617F -driven MPN. Conclusion LCL-161 may be therapeutically useful in MPN, in particular when exogenous TNFα signaling is blocked. NFĸB activation is a characteristic feature of JAK2 V617F mutant cells and this sensitizes them to SMAC mimetic induced killing even in the absence of TNFα. However, when exogenous TNFα is added, NFĸB is activated in both mutant and wild-type cells, abolishing the differential sensitivity. Moreover, JAK kinase activity is required for the differential sensitivity of JAK2 V617F mutant cells, suggesting that the addition of JAK2 inhibitors to SMAC mimetics would detract from the ability of SMAC mimetics to selectively target JAK2 V617F mutant cells. Instead, combination therapy with other agents that reduce inflammatory cytokines but preserve JAK2 signaling in mutant cells may be a more beneficial combination therapy in MPN. 

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