Product Citations: 346

Dependence of mitochondrial calcium signalling and dynamics on the disaggregase, CLPB.

In Nature Communications on 21 March 2025 by D'Angelo, D., Sánchez-Vázquez, V. H., et al.

Cells utilize protein disaggregases to avoid abnormal protein aggregation that causes many diseases. Among these, caseinolytic peptidase B protein homolog (CLPB) is localized in the mitochondrial intermembrane space and linked to human disease. Upon CLPB loss, MICU1 and MICU2, regulators of the mitochondrial calcium uniporter complex (mtCU), and OPA1, a main mediator of mitochondrial fusion, become insoluble but the functional outcome remains unclear. In this work we demonstrate that CLPB is required to maintain mitochondrial calcium signalling and fusion dynamics. CLPB loss results in altered mtCU composition, interfering with mitochondrial calcium uptake independently of cytosolic calcium and mitochondrial membrane potential. Additionally, OPA1 decreases, and aggregation occurs, accompanied by mitochondrial fragmentation. Disease-associated mutations in the CLPB gene present in skin fibroblasts from patients also display mitochondrial calcium and structural changes. Thus, mtCU and fusion activity are dependent on CLPB, and their impairments might contribute to the disease caused by CLPB variants.
© 2025. The Author(s).

  • Cell Biology

Creating Optimal Western Blot Conditions for OPA1 Isoforms in Skeletal Muscle Cells and Tissue.

In Current Protocols on 1 February 2025 by Mungai, M., Crabtree, A., et al.

OPA1 is a dynamin-related GTPase that modulates mitochondrial dynamics and cristae integrity. Humans carry eight different isoforms of OPA1 and mice carry five, all of which are expressed as short- or long-form isoforms. These isoforms contribute to OPA1's ability to control mitochondrial energetics and DNA maintenance. However, western blot isolation of all long and short isoforms of OPA1 can be difficult. To address this issue, we developed an optimized western blot protocol based on improving running time to isolate five different isoforms of OPA1 in mouse cells and tissues. This protocol can be applied to study changes in mitochondrial structure and function. © 2025 The Author(s). Current Protocols published by Wiley Periodicals LLC. Basic Protocol: Western Blot Protocol for Isolating OPA1 Isoforms in Mouse Primary Skeletal Muscle Cells.
© 2025 The Author(s). Current Protocols published by Wiley Periodicals LLC.

Cannabidiol reshapes the gut microbiome to promote endurance exercise in mice.

In Experimental & Molecular Medicine on 1 February 2025 by Chen, S., Lee, Y. B., et al.

Cannabidiol (CBD), a nonpsychoactive compound from Cannabis, has various bioactive functions in humans and animals. Evidence suggests that CBD promotes muscle injury recovery in athletes, but whether and how CBD improves endurance performance remains unclear. Here we investigated the effects of CBD treatment on exercise performance in mice and assessed whether this effect involves the gut microbiome. CBD administration significantly increased treadmill running performance in mice, accompanied by an increase in oxidative myofiber composition. CBD also increased mitochondrial biogenesis and the expression of associated genes such as PGC-1α, phosphorylated CREB and AMPK in muscle tissue. Interestingly, CBD altered the composition of the gut microbiome, and antibiotic treatment reduced the muscle endurance-enhancing effects of CBD and mitochondrial biogenesis. We isolated Bifidobacterium animalis, a microbe increased by CBD administration, and named it KBP-1. Treatment with B. animalis KBP-1 in mice resulted in improved running performance. Whole-genome analysis revealed that B. animalis KBP-1 presented high expression of genes involved in branched-chain amino acid biosynthesis, expression of branched-chain amino acid release pumps and metabolism of lactic acid. In summary, our study identified CBD and B. animalis KBP-1 as potential endurance exercise-promoting agents.
© 2025. The Author(s).

  • WB
  • Biochemistry and Molecular biology

Imbalanced mitochondrial dynamics in human and mouse PD brains

Preprint on BioRxiv : the Preprint Server for Biology on 28 January 2025 by Brown, H. J., Fan, R. Z., et al.

Mitochondrial dysfunction is a major pathogenic mechanism in Parkinson’s disease (PD). Emerging studies have shown that dysregulation in mitochondrial dynamics (fission/fusion/movement) has a major negative impact on mitochondria - both morphologically and functionally. Partial genetic deletion and pharmacological inhibition of the mitochondrial fission dynamin-related protein 1 (Drp1) have been demonstrated to be beneficial in experimental models of PD. However, the expression of DRP1 (and other fission and fusion genes/proteins) has not been investigated in the brains of Parkinson’s patients. Without these data, the question remains whether targeting DRP1 is a valid therapeutic target for PD. To address this gap of knowledge, first, we used post-mortem substantia nigra specimens of Parkinson’s patients and controls. Significant increases in the levels of both DNM1L , which encodes DRP1, as well as the DRP1 protein were detected in Parkinson’s patients. Immunostaining revealed increased DRP1 expression in dopamine (DA) neurons, astrocytes, and microglia. In addition to DRP1, the levels of other fission and fusion genes/proteins were also altered in Parkinson’s patients. To complement these human studies and given the significant role of α-synuclein in PD pathogenesis, we performed time-course studies (3-, 6- and 12-month) using transgenic mice overexpressing human wild-type SNCA under the mouse Thy-1 promoter. As early as 6 months old, we detected an upregulation of Dnm1l and Drp1 in the nigral DA neurons of the SNCA mice as compared to their WT littermates. Furthermore, these mutant animals exhibited more Drp1 phosphorylation at serine 616, which promotes its translocation to mitochondria to induce fragmentation. Together, this study shows an upregulation of DRP1/Drp1 and alterations in other fission/fusion proteins in both human and mouse PD brains, leading to a pro-fission phenotype, providing additional evidence that blocking mitochondrial fission or promoting fusion is a potential therapeutic strategy for PD.

  • Cell Biology

Prohibitin 2 is a Key Regulator of T Cell Proliferation and Effector Functions

Preprint on BioRxiv : the Preprint Server for Biology on 25 December 2024 by Vogt, J. F., Merkwirth, C., et al.

Prohibitin 2 (PHB2) is a highly conserved protein with essential roles in cell homeostasis and survival across different cell types. Previous studies have shown that the deletion of PHB2 results in an arrest in proliferation due to impaired mitochondrial function regulated by the dynamin-like GTPase OPA1. The function of PHB2 in immune cells remains unclear, however, some studies suggest that PHB2 plays a role in the cell membranes of B and T cells. In order to elucidate the role of PHB2 in immune cells, we generated PHB2-deficient T cells. Our findings reveal a pivotal role for PHB2 in the proliferation and differentiation of T cells. PHB2 deficiency inhibits T cell proliferation by inducing a cell cycle arrest at the G1 to S phase, thereby preventing the differentiation into effector T cells. Furthermore, in contrast to previous reports, T cells lacking PHB2 are more resistant to apoptosis. Metabolic analysis reveals that PHB2-deficient T cells fail to upregulate their glycolysis and oxidative phosphorylation upon activation, thus rendering them incapable to proliferate.

  • Mus musculus (House mouse)
  • Immunology and Microbiology
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