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Life Science Alliance Aug 2024In cells, mitochondria undergo constant fusion and fission. An essential factor for fission is the mammalian dynamin-related protein 1 (Drp1). Dysregulation of Drp1 is...
In cells, mitochondria undergo constant fusion and fission. An essential factor for fission is the mammalian dynamin-related protein 1 (Drp1). Dysregulation of Drp1 is associated with neurodegenerative diseases including Parkinson's, cardiovascular diseases and cancer, making Drp1 a pivotal biomarker for monitoring mitochondrial status and potential pathophysiological conditions. Here, we developed nanobodies (Nbs) as versatile binding molecules for proteomics, advanced microscopy and live cell imaging of Drp1. To specifically enrich endogenous Drp1 with interacting proteins for proteomics, we functionalized high-affinity Nbs into advanced capture matrices. Furthermore, we detected Drp1 by bivalent Nbs combined with site-directed fluorophore labelling in super-resolution STORM microscopy. For real-time imaging of Drp1, we intracellularly expressed fluorescently labelled Nbs, so-called chromobodies (Cbs). To improve the signal-to-noise ratio, we further converted Cbs into a "turnover-accelerated" format. With these imaging probes, we visualized the dynamics of endogenous Drp1 upon compound-induced mitochondrial fission in living cells. Considering the wide range of research applications, the presented Nb toolset will open up new possibilities for advanced functional studies of Drp1 in disease-relevant models.
Topics: Dynamins; Mitochondrial Dynamics; Humans; Single-Domain Antibodies; Mitochondria; Proteomics; Animals; Protein Binding; HeLa Cells; Mitochondrial Proteins
PubMed: 38816213
DOI: 10.26508/lsa.202402608 -
Military Medical Research May 2024Mitochondria, the most crucial energy-generating organelles in eukaryotic cells, play a pivotal role in regulating energy metabolism. However, their significance extends... (Review)
Review
Mitochondria, the most crucial energy-generating organelles in eukaryotic cells, play a pivotal role in regulating energy metabolism. However, their significance extends beyond this, as they are also indispensable in vital life processes such as cell proliferation, differentiation, immune responses, and redox balance. In response to various physiological signals or external stimuli, a sophisticated mitochondrial quality control (MQC) mechanism has evolved, encompassing key processes like mitochondrial biogenesis, mitochondrial dynamics, and mitophagy, which have garnered increasing attention from researchers to unveil their specific molecular mechanisms. In this review, we present a comprehensive summary of the primary mechanisms and functions of key regulators involved in major components of MQC. Furthermore, the critical physiological functions regulated by MQC and its diverse roles in the progression of various systemic diseases have been described in detail. We also discuss agonists or antagonists targeting MQC, aiming to explore potential therapeutic and research prospects by enhancing MQC to stabilize mitochondrial function.
Topics: Humans; Mitochondria; Mitophagy; Mitochondrial Dynamics
PubMed: 38812059
DOI: 10.1186/s40779-024-00536-5 -
Journal of Orthopaedic Surgery and... May 2024The larval zebrafish tail fin can completely regenerate in 3 days post amputation. mTOR, the main regulator of cell growth and metabolism, plays an essential role in...
BACKGROUND
The larval zebrafish tail fin can completely regenerate in 3 days post amputation. mTOR, the main regulator of cell growth and metabolism, plays an essential role in regeneration. Lots of studies have documented the role of mTOR in regeneration. However, the mechanisms involved are still not fully elucidated.
MATERIALS AND RESULTS
This study aimed to explore the role and mechanism of mTOR in the regeneration of larval zebrafish tail fins. Initially, the spatial and temporal expression of mTOR signaling in the larval fin was examined, revealing its activation following tail fin amputation. Subsequently, a mTOR knockout (mTOR-KO) zebrafish line was created using CRISPR/Cas9 gene editing technology. The investigation demonstrated that mTOR depletion diminished the proliferative capacity of epithelial and mesenchymal cells during fin regeneration, with no discernible impact on cell apoptosis. Insight from SMART-seq analysis uncovered alterations in the cell cycle, mitochondrial functions and metabolic pathways when mTOR signaling was suppressed during fin regeneration. Furthermore, mTOR was confirmed to enhance mitochondrial functions and Ca activation following fin amputation. These findings suggest a potential role for mTOR in promoting mitochondrial fission to facilitate tail fin regeneration.
CONCLUSION
In summary, our results demonstrated that mTOR played a key role in larval zebrafish tail fin regeneration, via promoting mitochondrial fission and proliferation of blastema cells.
Topics: Animals; Zebrafish; TOR Serine-Threonine Kinases; Regeneration; Cell Proliferation; Animal Fins; Zebrafish Proteins; Tail; Larva; Mitochondria; Mutation; Signal Transduction; Mitochondrial Dynamics
PubMed: 38812038
DOI: 10.1186/s13018-024-04802-z -
BMC Cardiovascular Disorders May 2024Myocardial ischemia-reperfusion injury (I/RI) is a major cause of perioperative cardiac-related adverse events and death. Studies have shown that sevoflurane...
BACKGROUND
Myocardial ischemia-reperfusion injury (I/RI) is a major cause of perioperative cardiac-related adverse events and death. Studies have shown that sevoflurane postconditioning (SpostC), which attenuates I/R injury and exerts cardioprotective effects, regulates mitochondrial dynamic balance via HIF-1α, but the exact mechanism is unknown. This study investigates whether the PI3K/AKT pathway in SpostC regulates mitochondrial dynamic balance by mediating HIF-1α, thereby exerting myocardial protective effects.
METHODS
The H9C2 cardiomyocytes were cultured to establish the hypoxia-reoxygenation (H/R) model and randomly divided into 4 groups: Control group, H/R group, sevoflurane postconditioning (H/R + SpostC) group and PI3K/AKT blocker (H/R + SpostC + LY) group. Cell survival rate was determined by CCK-8; Apoptosis rate was determined by flow cytometry; mitochondrial membrane potential was evaluated by Mito Tracker™ Red; mRNA expression levels of AKT, HIF-1α, Opa1and Drp1 were detected by quantitative real-time polymerase chain reaction (qRT-PCR); Western Blot assay was used to detect the protein expression levels of AKT, phosphorylated AKT (p-AKT), HIF-1α, Opa1 and Drp1.
RESULTS
Compared with the H/R group, the survival rate of cardiomyocytes in the H/R + SpostC group increased, the apoptosis rate decreased and the mitochondrial membrane potential increased. qRT-PCR showed that the mRNA expression of HIF-1α and Opa1 were higher in the H/R + SpostC group compared with the H/R group, whereas the transcription level of Drp1 was lower in the H/R + SpostC group. In the H/R + SpostC + LY group, the mRNA expression of HIF-1α was lower than the H/R + SpostC group. There was no difference in the expression of Opa1 mRNA between the H/R group and the H/R + SpostC + LY group. WB assay results showed that compared with the H/R group, the protein expression levels of HIF-1α, Opa1, P-AKT were increased and Drp1 protein expression levels were decreased in the H/R + SpostC group. HIF-1α, P-AKT protein expression levels were decreased in the H/R + SpostC + LY group compared to the H/R + SpostC group.
CONCLUSION
SpostC mediates HIF-1α-regulated mitochondrial fission and fusion-related protein expression to maintain mitochondrial dynamic balance by activating the PI3K/AKT pathway and increasing AKT phosphorylation, thereby attenuating myocardial I/R injury.
Topics: Hypoxia-Inducible Factor 1, alpha Subunit; Proto-Oncogene Proteins c-akt; Animals; Myocytes, Cardiac; Sevoflurane; Signal Transduction; Myocardial Reperfusion Injury; Mitochondrial Dynamics; Cell Line; Rats; Apoptosis; Phosphatidylinositol 3-Kinase; Mitochondria, Heart; Membrane Potential, Mitochondrial; Cell Hypoxia; Dynamins; GTP Phosphohydrolases; Phosphoinositide-3 Kinase Inhibitors; Cytoprotection; Ischemic Postconditioning; Phosphorylation
PubMed: 38811893
DOI: 10.1186/s12872-024-03868-1 -
PloS One 2024In this study, we aimed to investigate the protective effects of Panax notoginseng and leech (PL) on renal fibrosis and explore the mechanisms underlying their actions....
In this study, we aimed to investigate the protective effects of Panax notoginseng and leech (PL) on renal fibrosis and explore the mechanisms underlying their actions. For this study, we created an adenine-induced renal fibrosis model in SD rats to investigate the protective effect of PL on renal fibrosis and explore its underlying mechanism. Initially, we assessed the renal function in RF rats and found that Scr, BUN, and urine protein content decreased after PL treatment, indicating the protective effect of PL on renal function. Histological analysis using HE and Masson staining revealed that PL reduced inflammatory cell infiltration and decreased collagen fiber deposition in renal tissue. Subsequently, we analyzed the levels of α-SMA, Col-IV, and FN, which are the main components of the extracellular matrix (ECM), using IHC, RT-qPCR, and WB. The results demonstrated that PL was effective in reducing the accumulation of ECM, with PL1-2 showing the highest effectiveness. To further understand the underlying mechanisms, we conducted UPLC-MS/MS analysis on the incoming components of the PL1-2 group. The results revealed several associations between the differential components and antioxidant and mitochondrial functions. This was further confirmed by enzyme-linked immunosorbent assay and biochemical indexes, which showed that PL1-2 ameliorated oxidative stress by reducing ROS and MDA production and increasing GSH and SOD levels. Additionally, transmission electron microscopy results indicated that PL1-2 promoted partial recovery of mitochondrial morphology and cristae. Finally, using RT-qPCR and WB, an increase in the expression of mitochondrial fusion proteins Mfn1, Mfn2, and Opa1 after PL1-2 treatment was observed, coupled with a decline in the expression and phosphorylation of mitochondrial cleavage proteins Fis and Drp1. These findings collectively demonstrate that PL1-2 ameliorates renal fibrosis by reducing oxidative stress and restoring mitochondrial balance.
Topics: Animals; Panax notoginseng; Fibrosis; Mitochondria; Rats; Rats, Sprague-Dawley; Leeches; Male; Kidney; Kidney Diseases; Oxidative Stress; Disease Models, Animal; Extracellular Matrix; Mitochondrial Dynamics
PubMed: 38809875
DOI: 10.1371/journal.pone.0303906 -
Journal of Ovarian Research May 2024Zinc (Zn) is a crucial trace element essential for human growth and development, particularly for reproductive health. Previous research has shown a decrease in serum...
Zinc (Zn) is a crucial trace element essential for human growth and development, particularly for reproductive health. Previous research has shown a decrease in serum zinc concentration with age and individuals with conditions such as polycystic ovary syndrome (PCOS) and diabetes mellitus. However, the specific effects of zinc deficiency on the female reproductive system, especially ovarian function, are not fully understood. In our study, we observed a significant reduction in the total number of follicles and mature follicles in the zinc deficiency group. This reduction correlated with decreased level of anti-Mullerian hormone (AMH) and abnormal gene expression affecting hormone secretion regulation. Furthermore, we found that zinc deficiency disrupted mitochondrial dynamics, leading to oxidative stress in the ovaries, which further inhibited autophagy and increased ovarian apoptosis. These changes ultimately resulted in the failure of germinal vesicle breakdown (GVBD) and reduced oocyte quality. Meanwhile, administration of zinc glycine effectively alleviated the oocyte meiotic arrest caused by dietary zinc deficiency. In conclusion, our findings demonstrated that dietary zinc deficiency can affect hormone secretion and follicle maturation by impairing mitochondrial function and autophagy.
Topics: Female; Zinc; Ovarian Follicle; Mitochondria; Animals; Autophagy; Oocytes; Anti-Mullerian Hormone; Oxidative Stress; Mice; Apoptosis; Humans
PubMed: 38807213
DOI: 10.1186/s13048-024-01442-z -
Chronic spindle assembly checkpoint activation causes myelosuppression and gastrointestinal atrophy.EMBO Reports May 2024Interference with microtubule dynamics in mitosis activates the spindle assembly checkpoint (SAC) to prevent chromosome segregation errors. The SAC induces mitotic...
Interference with microtubule dynamics in mitosis activates the spindle assembly checkpoint (SAC) to prevent chromosome segregation errors. The SAC induces mitotic arrest by inhibiting the anaphase-promoting complex (APC) via the mitotic checkpoint complex (MCC). The MCC component MAD2 neutralizes the critical APC cofactor, CDC20, preventing exit from mitosis. Extended mitotic arrest can promote mitochondrial apoptosis and caspase activation. However, the impact of mitotic cell death on tissue homeostasis in vivo is ill-defined. By conditional MAD2 overexpression, we observe that chronic SAC activation triggers bone marrow aplasia and intestinal atrophy in mice. While myelosuppression can be compensated for, gastrointestinal atrophy is detrimental. Remarkably, deletion of pro-apoptotic Bim/Bcl2l11 prevents gastrointestinal syndrome, while neither loss of Noxa/Pmaip or co-deletion of Bid and Puma/Bbc3 has such a protective effect, identifying BIM as rate-limiting apoptosis effector in mitotic cell death of the gastrointestinal epithelium. In contrast, only overexpression of anti-apoptotic BCL2, but none of the BH3-only protein deficiencies mentioned above, can mitigate myelosuppression. Our findings highlight tissue and cell-type-specific survival dependencies in response to SAC perturbation in vivo.
PubMed: 38806674
DOI: 10.1038/s44319-024-00160-3 -
Light, Science & Applications May 2024Structured illumination microscopy (SIM) has emerged as a promising super-resolution fluorescence imaging technique, offering diverse configurations and computational...
Structured illumination microscopy (SIM) has emerged as a promising super-resolution fluorescence imaging technique, offering diverse configurations and computational strategies to mitigate phototoxicity during real-time imaging of biological specimens. Traditional efforts to enhance system frame rates have concentrated on processing algorithms, like rolling reconstruction or reduced frame reconstruction, or on investments in costly sCMOS cameras with accelerated row readout rates. In this article, we introduce an approach to elevate SIM frame rates and region of interest (ROI) coverage at the hardware level, without necessitating an upsurge in camera expenses or intricate algorithms. Here, parallel acquisition-readout SIM (PAR-SIM) achieves the highest imaging speed for fluorescence imaging at currently available detector sensitivity. By using the full frame-width of the detector through synchronizing the pattern generation and image exposure-readout process, we have achieved a fundamentally stupendous information spatial-temporal flux of 132.9 MPixels · s, 9.6-fold that of the latest techniques, with the lowest SNR of -2.11 dB and 100 nm resolution. PAR-SIM demonstrates its proficiency in successfully reconstructing diverse cellular organelles in dual excitations, even under conditions of low signal due to ultra-short exposure times. Notably, mitochondrial dynamic tubulation and ongoing membrane fusion processes have been captured in live COS-7 cell, recorded with PAR-SIM at an impressive 408 Hz. We posit that this novel parallel exposure-readout mode not only augments SIM pattern modulation for superior frame rates but also holds the potential to benefit other complex imaging systems with a strategic controlling approach.
PubMed: 38806501
DOI: 10.1038/s41377-024-01464-8 -
Journal of Inflammation Research 2024Upon uptake by stressed cells, functional mitochondria can perform their normal functions, ultimately enhancing the survival of host cells. However, despite the...
BACKGROUND
Upon uptake by stressed cells, functional mitochondria can perform their normal functions, ultimately enhancing the survival of host cells. However, despite the promising results of this approach, there is still a lack of understanding of the specific relationship between nerve cells and functional mitochondria.
METHODS
Functional mitochondria (F-Mito) were isolated from bone marrow-derived mesenchymal stem cells (BMSCs). The ability of microglia cells to internalize F-Mito was evaluated using a middle cerebral artery occlusion (MCAO) model in C57BL/6J mice and an oxygen-glucose deprivation/reoxygenation (OGD/R) cell model. After OGD/R and F-Mito treatment, the temporal dynamics of intracellular reactive oxygen species (ROS) levels were examined.The relationship between ROS levels and F-Mito uptake was assessed at the individual cell level using MitoSOX, Mitotracker, and HIF-1α labeling.
RESULTS
Our findings indicate that microglia cells exhibit enhanced mitochondrial uptake compared to astrocytes. Furthermore, internalized F-Mito reduced ROS levels and HIF-1α levels. Importantly, we found that the ROS response in microglia cells following ischemia is a critical regulator of F-Mito internalization, and promoting autophagy in microglia cells might reduce the uptake of ROS and HIF-1α levels.
CONCLUSION
It is verified that F-Mito derived from BMSCs play a protective role in ischemia-reperfusion injury, as their weakening reduces microglial cell activation and alleviates neuroinflammation.
PubMed: 38803690
DOI: 10.2147/JIR.S463692 -
Scientific Reports May 2024Comprehending the phylogeography of invasive organisms enhances our insight into their distribution dynamics, which is instrumental for the development of effective...
Comprehending the phylogeography of invasive organisms enhances our insight into their distribution dynamics, which is instrumental for the development of effective prevention and management strategies. In China, Pomacea canaliculata and Pomacea maculata are the two most widespread and damaging species of the non-native Pomacea spp.. Given this species' rapid spread throughout country, it is urgent to investigate the genetic diversity and structure of its different geographic populations, a task undertaken in the current study using the COI and ITS1 mitochondrial and ribosomal DNA genes, respectively. The result of this study, based on a nationwide systematic survey, a collection of Pomacea spp., and the identification of cryptic species, showed that there is a degree of genetic diversity and differentiation in P. canaliculata, and that all of its variations are mainly due to differences between individuals within different geographical populations. Indeed, this species contains multiple haplotypes, but none of them form a systematic geographical population structure. Furthermore, the COI gene exhibits higher genetic diversity than the ITS1 gene. Our study further clarifies the invasive pathways and dispersal patterns of P. canaliculata in China to provide a theoretical basis.
Topics: China; Animals; Electron Transport Complex IV; Genetic Variation; Genetics, Population; Haplotypes; Phylogeography; Phylogeny; Introduced Species; DNA, Ribosomal Spacer; Gastropoda
PubMed: 38802502
DOI: 10.1038/s41598-024-62554-6