bims-curels Biomed News
on Leigh syndrome
Issue of 2024‒07‒21
four papers selected by
Cure Mito Foundation

  1. Front Psychiatry. 2024 ;15 1389093
      Introduction: Mitochondrial diseases are known inborn errors affecting energy metabolism and are as common as chronic diseases such as diabetes, affecting approximately 1 in 5,000 people. The role of mitochondrial diseases/dysfunction has been highlighted in neurodevelopmental disorders like ASD, ADHD, intellectual disability, and speech delay, as well as various psychiatric conditions. Neurodevelopmental disorders are increasingly recognized as having behavioral and psychiatric symptoms. Our study aimed to investigate reports of mitochondrial disorders, noting neurodevelopmental disorders and psychiatric/behavioral conditions.Methods: This was done through a systematic review of literature from PubMed/MEDLINE, Scopus, and Cochrane Library up to November 2022.
    Results: We found 277 publications, of which 139 met the inclusion criteria. We mostly found review articles with mention of mitochondrial dysfunction/disorder in relation to ASD with brief mentions of psychiatric/behavioral comorbidities.
    Discussion: This suggests a need for broader research efforts beyond ASD to understand the relationship between mitochondrial disorder or dysfunction and various neurodevelopmental and psychiatric/behavioral comorbidities.
    Keywords:  ADHD; ASD; anxiety; depression; mitochondrial disorder; mitochondrial dysfunction; neurodevelopmental disorder; psychiatric disorder
  2. Physiol Res. 2024 Jul 17.
      Disorders of ATP synthase, the key enzyme in mitochondrial energy supply, belong to the most severe metabolic diseases, manifesting as early-onset mitochondrial encephalo-cardiomyopathies. Since ATP synthase subunits are encoded by both mitochondrial and nuclear DNA, pathogenic variants can be found in either genome. In addition, the biogenesis of ATP synthase requires several assembly factors, some of which are also hotspots for pathogenic variants. While variants of MT-ATP6 and TMEM70 represent the most common cases of mitochondrial and nuclear DNA mutations respectively, the advent of next-generation sequencing has revealed new pathogenic variants in a number of structural genes and TMEM70, sometimes with truly peculiar genetics. Here we present a systematic review of the reported cases and discuss biochemical mechanisms, through which they are affecting ATP synthase. We explore how the knowledge of pathophysiology can improve our understanding of enzyme biogenesis and function.
  3. Matrix Biol. 2024 Jul 13. pii: S0945-053X(24)00093-3. [Epub ahead of print]
      Post-mitotic, non-proliferative dermal fibroblasts have crucial functions in maintenance and restoration of tissue homeostasis. They are involved in essential processes such as wound healing, pigmentation and hair growth, but also tumor development and aging-associated diseases. These processes are energetically highly demanding and error prone when mitochondrial damage occurs. However, mitochondrial function in fibroblasts and the influence of mitochondrial dysfunction on fibroblast-specific demands are still unclear. To address these questions, we created a mouse model in which accelerated cell-specific mitochondrial DNA (mtDNA) damage accumulates. We crossed mice carrying a dominant-negative mutant of the mitochondrial replicative helicase Twinkle (RosaSTOP system) with mice that express fibroblast-specific Cre Recombinase (Collagen1A2 CreERT) which can be activated by Tamoxifen (TwinkleFIBRO). Thus, we are able to induce mtDNA deletions and duplications in specific cells, a process which resembles the physiological aging process in humans, where this damage accumulates in all tissues. Upon proliferation in vitro, Tamoxifen induced Twinkle fibroblasts deplete most of their mitochondrial DNA which, although not disturbing the stoichiometry of the respiratory chain complexes, leads to reduced ROS production and mitochondrial membrane potential as well as an anti-inflammatory and anti-fibrotic profile of the cells. In Sodium Azide treated wildtype fibroblasts, without a functioning respiratory chain, we observe the opposite, a rather pro-inflammatory and pro-fibrotic signature. Upon accumulation of mitochondrial DNA mutations in vivo the TwinkleFIBRO mice are protected from fibrosis development induced by intradermal Bleomycin injections. This is due to dampened differentiation of the dermal fibroblasts into α-smooth-muscle-actin positive myofibroblasts in TwinkleFIBRO mice. We thus provide evidence for striking differences of the impact that mtDNA mutations have in contrast to blunted mitochondrial function in dermal fibroblasts and skin homeostasis. These data contribute to improved understanding of mitochondrial function and dysfunction in skin and provide mechanistic insight into potential targets to treat skin fibrosis in the future.
    Keywords:  Twinkle helicase; differentiation; mitochondrial DNA; myofibroblasts; skin fibrosis; α−smooth-muscle-actin
  4. Am J Bioeth. 2024 Jul 15. 1-17
      Clinical researchers should help respect the autonomy and promote the well-being of prospective study participants by helping them make voluntary, informed decisions about enrollment. However, participants often exhibit poor understanding of important information about clinical research. Bioethicists have given special attention to "misconceptions" about clinical research that can compromise participants' decision-making, most notably the "therapeutic misconception." These misconceptions typically involve false beliefs about a study's purpose, or risks or potential benefits for participants. In this article, we describe a misconception involving false beliefs about a study's potential benefits for non-participants, or its expected social value. This social value misconception can compromise altruistically motivated participants' decision-making, potentially threatening their autonomy and well-being. We show how the social value misconception raises ethical concerns for inherently low-value research, hyped research, and even ordinary research, and advocate for empirical and normative work to help understand and counteract this misconception's potential negative impacts on participants.
    Keywords:  Social value; altruism; autonomy; clinical research; misconception; participant decision-making; study enrollment