bims-minfam 2024-04-28 papers

Issue of 2024–04–28
six papers selected by
Ayesh Seneviratne, Western University

Mitochondrion. 2024 Apr 23. pii: S1567-7249(24)00044-8. [Epub ahead of print] 101886

Mitochondrial dysfunction, a weakest link of network of aging, relation to innate intramitochondrial immunity of DNA recognition receptors.

Dun-Xian Tan.

Aging probably is the most complexed process in biology. It is manifested by a variety of hallmarks. These hallmarks weave a network of aging; however, each hallmark is not uniformly strong for the network. It is the weakest link determining the strengthening of the network of aging, or the maximum lifespan of an organism. Therefore, only improvement of the weakest link has the chance to increase the maximum lifespan but not others. We hypothesize that mitochondrial dysfunction is the weakest link of the network of aging. It may origin from the innate intramitochondrial immunity related to the activity of pathogen DNA recognition receptors. These receptors recognize mtDNA as the PAMP or DAMP to initiate the immune or inflammatory reactions. Evidence has shown that several of these receptors including TLR9, cGAS and IFI16 can be translocated into mitochondria. The potentially intramitochondrial pathogen DNA recognition receptors have the capacity to attack the exposed second structures of the mtDNA during its transcriptional or especially the replication processed, leading to the mtDNA mutation, deletion, heteroplasmy colonization, mitochondrial dysfunction, and alterations of other hallmarks, as well as aging. Pre-consumption of the intramitochondrial pathogen DNA recognition receptors by medical interventions including development of mitochondrial targeted small molecule which can neutralization of these receptors may retard or even reverse the aging to significantly improve the maximum lifespan of the organisms.

Keywords: Aging; DNA recognition receptors; Hallmarks of aging; Innate intracellular immunity; Mitochondria dysfunction; mtDNA deletion

DOI: https://doi.org/10.1016/j.mito.2024.101886

Cells. 2024 Apr 19. pii: 712. [Epub ahead of print]13(8):

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

Xinliang Chen, Chaonan Liu, Junping Wang, Changhong Du.

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

Keywords: cardiovascular disease; hematopoietic stem cell; lifestyle; myeloid bias

DOI: https://doi.org/10.3390/cells13080712

Biomolecules. 2024 Apr 16. pii: 485. [Epub ahead of print]14(4):

Cell Senescence in Heterotopic Ossification.

Robert J Pignolo, Frederick S Kaplan, Haitao Wang.

The formation of bone outside the normal skeleton, or heterotopic ossification (HO), occurs through genetic and acquired mechanisms. Fibrodysplasia ossificans progressiva (FOP), the most devastating genetic condition of HO, is due to mutations in the ACVR1/ALK2 gene and is relentlessly progressive. Acquired HO is mostly precipitated by injury or orthopedic surgical procedures but can also be associated with certain conditions related to aging. Cellular senescence is a hallmark of aging and thought to be a tumor-suppressive mechanism with characteristic features such as irreversible growth arrest, apoptosis resistance, and an inflammatory senescence-associated secretory phenotype (SASP). Here, we review possible roles for cellular senescence in HO and how targeting senescent cells may provide new therapeutic approaches to both FOP and acquired forms of HO.

Keywords: cellular senescence; fibrodysplasia ossificans progressiva; heterotopic ossification; senotherapeutics

DOI: https://doi.org/10.3390/biom14040485

Clin Sci (Lond). 2024 Apr 24. 138(8): 515-536

Astrocytes at the intersection of ageing, obesity, and neurodegeneration.

Wyn Firth, Katherine R Pye, Paul G Weightman Potter.

Once considered passive cells of the central nervous system (CNS), glia are now known to actively maintain the CNS parenchyma; in recent years, the evidence for glial functions in CNS physiology and pathophysiology has only grown. Astrocytes, a heterogeneous group of glial cells, play key roles in regulating the metabolic and inflammatory landscape of the CNS and have emerged as potential therapeutic targets for a variety of disorders. This review will outline astrocyte functions in the CNS in healthy ageing, obesity, and neurodegeneration, with a focus on the inflammatory responses and mitochondrial function, and will address therapeutic outlooks.

Keywords: aging; astrocytes; glial cell; immunometabolism; neurodegeneration; obesity

DOI: https://doi.org/10.1042/CS20230148

bioRxiv. 2024 Apr 15. pii: 2024.04.12.589110. [Epub ahead of print]

Mitochondria inside acute myeloid leukemia cells hydrolyze ATP to resist chemotherapy.

James T Hagen, Mclane M Montgomery, Raphael T Aruleba, Brett R Chrest, Thomas D Green, Miki Kassai, Tonya N Zeczycki, Cameron A Schmidt, Debajit Bhowmick, Su-Fern Tan, David J Feith, Charles E Chalfant, Thomas P Loughran, Darla Liles, Mark D Minden, Aaron D Schimmer, Myles C Cabot, Joseph M Mclung, Kelsey H Fisher-Wellman.

Despite early optimism, therapeutics targeting oxidative phosphorylation (OxPhos) have faced clinical setbacks, stemming from their inability to distinguish healthy from cancerous mitochondria. Herein, we describe an actionable bioenergetic mechanism unique to cancerous mitochondria inside acute myeloid leukemia (AML) cells. Unlike healthy cells which couple respiration to the synthesis of ATP, AML mitochondria were discovered to support inner membrane polarization by consuming ATP. Because matrix ATP consumption allows cells to survive bioenergetic stress, we hypothesized that AML cells may resist cell death induced by OxPhos damaging chemotherapy by reversing the ATP synthase reaction. In support of this, targeted inhibition of BCL-2 with venetoclax abolished OxPhos flux without impacting mitochondrial membrane potential. In surviving AML cells, sustained polarization of the mitochondrial inner membrane was dependent on matrix ATP consumption. Mitochondrial ATP consumption was further enhanced in AML cells made refractory to venetoclax, consequential to downregulations in both the proton-pumping respiratory complexes, as well as the endogenous F 1 -ATPase inhibitor ATP5IF1 . In treatment-naive AML, ATP5IF1 knockdown was sufficient to drive venetoclax resistance, while ATP5IF1 overexpression impaired F 1 -ATPase activity and heightened sensitivity to venetoclax. Collectively, our data identify matrix ATP consumption as a cancer-cell intrinsic bioenergetic vulnerability actionable in the context of mitochondrial damaging chemotherapy.

DOI: https://doi.org/10.1101/2024.04.12.589110