ATFS-1 counteracts mitochondrial DNA damage by promoting repair over transcription.

The ability to balance conflicting functional demands is critical for ensuring organismal survival. The transcription and repair of the mitochondrial genome (mtDNA) requires separate enzymatic activities that can sterically compete1, suggesting a life-long trade-off between these two processes. Here in Caenorhabditis elegans, we find that the bZIP transcription factor ATFS-1/Atf5 (refs. 2,3) regulates this balance in favour of mtDNA repair by localizing to mitochondria and interfering with the assembly of the mitochondrial pre-initiation transcription complex between HMG-5/TFAM and RPOM-1/mtRNAP. ATFS-1-mediated transcriptional inhibition decreases age-dependent mtDNA molecular damage through the DNA glycosylase NTH-1/NTH1, as well as the helicase TWNK-1/TWNK, resulting in an enhancement in the functional longevity of cells and protection against decline in animal behaviour caused by targeted and severe mtDNA damage. Together, our findings reveal that ATFS-1 acts as a molecular focal point for the control of balance between genome expression and maintenance in the mitochondria.

Changes of Electrocardiogram and Myocardial Enzymes in Patients with Intracerebral Hemorrhage.

Purpose: Cardiac complications are common in patients with spontaneous intracerebral hemorrhage (ICH). The present study is aimed at observing the incidence of cardiac complications after ICH, so as at improving the understanding of the relationship between cardiac complications and ICH. Methods: This is a retrospective study on analyzing electrocardiogram (ECG) and serum myocardial enzyme of 208 patients with ICH admitted to a tertiary hospital from 2018 to 2019. For each patient, demographics, medical history, clinical presentation, ECG, serum myocardial enzyme, and head CT on admission were reviewed. Mortality was noted. Results: Among the 208 patients, 145 (69.71%) had one or more ECG abnormalities. The top three abnormalities were corrected QT interval (QTc) prolongation 52 (25%), ST depression 48 (23.08%), and T wave inversion 38 (18.27%). One hundred and thirty-nine patients (66.83%) had increased serum levels of at least one kind of myocardial enzyme, which were high-sensitive cardiac troponin T (hs-cTnT) 79 (37.98%), lactic dehydrogenase (LDH) 80 (38.46%), creatine kinase (CK) 57 (27.40%), and creatine kinase-myocardial subfraction (CKMB) 57 (27.40%). The logistic regression analysis showed the following: secondary intraventricular hemorrhage (SIVH) (odds ratio (OR) 5.32; 95% confidence interval (CI) 2.55-11.08; p < 0.001) and hematoma volume > 30 ml (OR 3.81; 95% CI 1.86-7.81; p < 0.001) were independent predictive factors of QTc prolongation; thalamus location (OR 5.79; 95% CI 1.94-17.28; p < 0.05), hematoma volume > 30 ml (OR 24.187; 95% CI 3.14-186.33; p < 0.05), insular involvement (OR 19.08; 95% CI 5.77-63.07; p < 0.001), and SIVH (OR 2.62; 95% CI 1.69-5.86; p < 0.05) were independent predictive factors of ST depression; insular involvement (OR 2.90; 95% CI 1.12-7.50; p < 0.05) and hematoma volume > 30 ml (OR 1.98; 95% CI 1.06-3.70; p < 0.05) were independent predictive factors of increase of CK; Glasgow Coma Scale (GCS) (OR 0.86; 95% CI 0.78-0.98; p < 0.05) and insular involvement (OR 5.56; 95% CI 1.98-15.62; p < 0.05) were independent predictive factors of increase of CKMB; SIVH (OR 2.05; 95% CI 1.07-3.92; p < 0.05) was independent predictive factor of increase of LDH; age (OR 1.03; 95% CI 1.01-1.06; p < 0.05), blood glucose on admission (OR 1.10; 95% CI 1.01-1.20; p < 0.05), and history of antiplatelet drug use (OR 3.50; 95% CI 1.01-12.12; p < 0.05) were independent predictive factors of hs-cTnT. All the injury indexes were not related to in-hospital mortality. Conclusion: The study suggests that insular involvement, hematoma volume > 30 ml, and SIVH are the strongest risk factors for ECG abnormalities and elevated myocardial enzymes after ICH followed which are the risk factors such as GCS, age, admission blood glucose, and ICH location in the thalamus.

Targeted Therapy of Tuberculous Meningitis in Rats with Methylprednisolone Composite Nanoparticles.

It was to investigate the targeted therapeutic effect of methylprednisolone (MPS) composite nanoparticles (NPs) on tuberculous meningitis (TBM) in rats. A total of 180 special pathogen-free (SPF) Sprague Dawley (SD) rats (male) were randomly and equally assigned to the normal control group, TBM infection group, and TBM treatment group. Those in the TBM infection group and the TBM treatment group were injected with Mycobacterium tuberculosis suspension via the tail vein. After the TBM model was established, rats in the TBM treatment group were injected intraperitoneally with methylprednisolone-nano sterically stabilized liposomes (MPS-NSSLs), and those in the normal control group were injected with an equal amount of normal saline. MPS-NSSLs were prepared, and their quality evaluation, encapsulation rate, drug-lipid ratio, and stability were detected. The particle size distribution of MPS-NSSLs was 95.4 ± 0.7 nm, showing a complete spherical structure, and the encapsulation rate was 91.24 ± 0.27 %, and the drug-lipid ratio was about 0.4. After 7 days of treatment, the water content of brain tissue in the TBM infection group was drastically superior to that in the control group (P<0.05); Evans blue (EB) content in the TBM infection group was dramatically superior to that in the control group (P<0.05). The TBM rat model was successfully established, and this model verified that MPS-NSSLs had the characteristics of high efficiency and low toxicity in the treatment of TBM rats.

Effect of Glucocorticoid Nanoliposomes on Vascular Endothelial Growth Factor Expression in Brain Tissue of Rats with Tuberculous Meningitis.

To investigate the effect of human brain-targeted nanoliposomes encapsulating methylprednisolone sodium succinate on the level of vascular endothelial growth factor (VEGF) in brain tissue of rats with tuberculous meningitis (TBM), the nanoliposome DSPE-125I-AIBZM-MPS was prepared. 180 rats were divided into normal control, TBM infection, and TBM treatment groups. The brain water content, Evans blue (EB) content, VEGF, and the gene and protein expression of receptors (Flt-1, Flk-1) of rats after modeling were measured. The brain water content and EB content in the TBM treatment group were significantly lower than those in the TBM infection group at 4 and 7 days after modeling (P < 0.05). The expression of VEGF and its receptor Flt-1 mRNA in the brain tissue of rats in the TBM infection group was significantly higher than that in the normal control group at 1, 4, and 7 days after modeling (P < 0.05). The expression of VEGF and its receptor Flt-1 mRNA in the brain tissue of rats in the TBM treatment group was significantly higher than that in the TBM infection group at 1, 4, and 7 days after modeling (P < 0.05). In summary, the prepared DSPE-125I-AIBZM-MPS nanoliposomes can effectively reduce brain water content and EB content and reduce the release of inflammatory factors of brain tissue in rats, playing a role in the treatment of TBM in rats by regulating the expression of VEGF and its receptor Flt-1 mRNA.

PINK1 and parkin shape the organism-wide distribution of a deleterious mitochondrial genome.

In multiple species, certain tissue types are prone to acquiring greater loads of mitochondrial genome (mtDNA) mutations relative to others, but the mechanisms that drive these heteroplasmy differences are unknown. We find that the conserved PTEN-induced putative kinase (PINK1/PINK-1) and the E3 ubiquitin-protein ligase parkin (PDR-1), which are required for mitochondrial autophagy (mitophagy), underlie stereotyped differences in heteroplasmy of a deleterious mitochondrial genome mutation (ΔmtDNA) between major somatic tissues types in Caenorhabditis elegans. We demonstrate that tissues prone to accumulating ΔmtDNA have lower mitophagy responses than those with low mutation levels. Moreover, we show that ΔmtDNA heteroplasmy increases when proteotoxic species that are associated with neurodegenerative disease and mitophagy inhibition are overexpressed in the nervous system. These results suggest that PINK1 and parkin drive organism-wide patterns of heteroplasmy and provide evidence of a causal link between proteotoxicity, mitophagy, and mtDNA mutation levels in neurons.

Optimization of the extraction and purification of Corydalis yanhusuo W.T. Wang based on the Q-marker uniform design method.

Corydalis yanhusuo W.T. Wang alkaloids are mainly divided into three categories: protoberberine, prototropine and aporphine alkaloids. Therefore, we have taken into account these three alkaloid contents when extracting and purifying crude drugs, which is essential for the quality control of C. yanhusuo and its derivative products. Herein, we investigated the feasibility of the Q-marker uniform design method in the optimization of the extraction and purification of C. yanhusuo. In this study, Q-marker-based comprehensive scoring (CS) and uniform design methods were used to optimize the extraction and purification of C. yanhusuo. The inspective factors included the solvent concentration, pH, liquid-solid ratio, extraction time and frequency. Then 8 Q-markers, the total alkaloid extraction and the extraction rate were considered as the evaluating indicators during the process. The results indicated that the optimal reflux extraction process of C. yanhusuo was as follows: a total amount of 20 times 70% ethanol (pH = 10 of diluted ammonia), heating and refluxing twice, and extracting each time for 60 min. The results of nine-resin screening exhibited that NKA-9 macroporous adsorption resin had the best separation and purification effect on 8 kinds of C. yanhusuo alkaloids with stronger enrichment. During the optimal enrichment process and elution conditions, the water-soluble impurities were washed off with 5 BV distilled water at a volume flow rate of 2 BV/h, and the elution solvent was 70% ethanol with an elution volume flow rate of 1.5 BV/h and an elution dosage of 12 BV. Additionally, the total alkaloids of the obtained product were over 50%, of which eight quality markers were (+)-corydaline 3.55%, tetrahydropalmatine 3.13%, coptisine 2.79%, palmatine hydrochloride 2.24%, dehydrocorydaline 13.11%, (R)-(+)-corypalmine 2.37%, protopine 2.71% and glaucine 14.03%. Our data demonstrated that the optimal extraction and purification process was stable and feasible, which was expected to provide an experimental basis and reference for the industrial production of C. yanhusuo.

Publisher Correction: Affinity purification of cell-specific mitochondria from whole animals resolves patterns of genetic mosaicism.

In the version of this Technical Report originally published, chromosome representations (indicated by black lines) were missing from Fig. 2a due to a technical error. The corrected version of Fig. 2a is shown below. This has now been amended in all online versions of the Technical Report.

Affinity purification of cell-specific mitochondria from whole animals resolves patterns of genetic mosaicism.

Although mitochondria are ubiquitous organelles, they exhibit tissue-specific morphology, dynamics and function. Here, we describe a robust approach to isolate mitochondria from specific cells of diverse tissue systems in Caenorhabditis elegans. Cell-specific mitochondrial affinity purification (CS-MAP) yields intact and functional mitochondria with exceptional purity and sensitivity (>96% enrichment, >96% purity, and single-cell and single-animal resolution), enabling comparative analyses of protein and nucleic acid composition between organelles isolated from distinct cellular lineages. In animals harbouring a mixture of mutant and wild-type mitochondrial genomes, we use CS-MAP to reveal subtle mosaic patterns of cell-type-specific heteroplasmy across large populations of animals (>10,000 individuals). We demonstrate that the germline is more prone to propagating deleterious mitochondrial genomes than somatic lineages, which we propose is caused by enhanced mtDNA replication in this tissue.

A Functional Role for the Epigenetic Regulator ING1 in Activity-induced Gene Expression in Primary Cortical Neurons.

Epigenetic regulation of activity-induced gene expression involves multiple levels of molecular interaction, including histone and DNA modifications, as well as mechanisms of DNA repair. Here we demonstrate that the genome-wide deposition of inhibitor of growth family member 1 (ING1), which is a central epigenetic regulatory protein, is dynamically regulated in response to activity in primary cortical neurons. ING1 knockdown leads to decreased expression of genes related to synaptic plasticity, including the regulatory subunit of calcineurin, Ppp3r1. In addition, ING1 binding at a site upstream of the transcription start site (TSS) of Ppp3r1 depends on yet another group of neuroepigenetic regulatory proteins, the Piwi-like family, which are also involved in DNA repair. These findings provide new insight into a novel mode of activity-induced gene expression, which involves the interaction between different epigenetic regulatory mechanisms traditionally associated with gene repression and DNA repair.

Par-1 regulates tissue growth by influencing hippo phosphorylation status and hippo-salvador association.

The evolutionarily conserved Hippo (Hpo) signaling pathway plays a pivotal role in organ size control by balancing cell proliferation and cell death. Here, we reported the identification of Par-1 as a regulator of the Hpo signaling pathway using a gain-of-function EP screen in Drosophila melanogaster. Overexpression of Par-1 elevated Yorkie activity, resulting in increased Hpo target gene expression and tissue overgrowth, while loss of Par-1 diminished Hpo target gene expression and reduced organ size. We demonstrated that par-1 functioned downstream of fat and expanded and upstream of hpo and salvador (sav). In addition, we also found that Par-1 physically interacted with Hpo and Sav and regulated the phosphorylation of Hpo at Ser30 to restrict its activity. Par-1 also inhibited the association of Hpo and Sav, resulting in Sav dephosphorylation and destabilization. Furthermore, we provided evidence that Par-1-induced Hpo regulation is conserved in mammalian cells. Taken together, our findings identified Par-1 as a novel component of the Hpo signaling network.