BCL11B and the NuRD complex cooperatively guard T-cell fate and inhibit OPA1-mediated mitochondrial fusion in T cells.

The nucleosome remodeling and histone deacetylase (NuRD) complex physically associates with BCL11B to regulate murine T-cell development. However, the function of NuRD complex in mature T cells remains unclear. Here, we characterize the fate and metabolism of human T cells in which key subunits of the NuRD complex or BCL11B are ablated. BCL11B and the NuRD complex bind to each other and repress natural killer (NK)-cell fate in T cells. In addition, T cells upregulate the NK cell-associated receptors and transcription factors, lyse NK-cell targets, and are reprogrammed into NK-like cells (ITNKs) upon deletion of MTA2, MBD2, CHD4, or BCL11B. ITNKs increase OPA1 expression and exhibit characteristically elongated mitochondria with augmented oxidative phosphorylation (OXPHOS) activity. OPA1-mediated elevated OXPHOS enhances cellular acetyl-CoA levels, thereby promoting the reprogramming efficiency and antitumor effects of ITNKs via regulating H3K27 acetylation at specific targets. In conclusion, our findings demonstrate that the NuRD complex and BCL11B cooperatively maintain T-cell fate directly by repressing NK cell-associated transcription and indirectly through a metabolic-epigenetic axis, providing strategies to improve the reprogramming efficiency and antitumor effects of ITNKs.

Force-induced tail-autotomy mitochondrial fission and biogenesis of matrix-excluded mitochondrial-derived vesicles for quality control.

Mitochondria constantly fuse and divide for mitochondrial inheritance and functions. Here, we identified a distinct type of naturally occurring fission, tail-autotomy fission, wherein a tail-like thin tubule protrudes from the mitochondrial body and disconnects, resembling autotomy. Next, utilizing an optogenetic mitochondria-specific mechanostimulator, we revealed that mechanical tensile force drives tail-autotomy fission. This force-induced fission involves DRP1/MFF and endoplasmic reticulum tubule wrapping. It redistributes mitochondrial DNA, producing mitochondrial fragments with or without mitochondrial DNA for different fates. Moreover, tensile force can decouple outer and inner mitochondrial membranes, pulling out matrix-excluded tubule segments. Subsequent tail-autotomy fission separates the matrix-excluded tubule segments into matrix-excluded mitochondrial-derived vesicles (MDVs) which recruit Parkin and LC3B, indicating the unique role of tail-autotomy fission in segregating only outer membrane components for mitophagy. Sustained force promotes fission and MDV biogenesis more effectively than transient one. Our results uncover a mechanistically and functionally distinct type of fission and unveil the role of tensile forces in modulating fission and MDV biogenesis for quality control, underscoring the heterogeneity of fission and mechanoregulation of mitochondrial dynamics.

Heterochromatin loosening by the Oct4 linker region facilitates Klf4 binding and iPSC reprogramming.

The success of Yamanaka factor reprogramming of somatic cells into induced pluripotent stem cells suggests that some factor(s) must remodel the nuclei from a condensed state to a relaxed state. How factor-dependent chromatin opening occurs remains unclear. Using FRAP and ATAC-seq, we found that Oct4 acts as a pioneer factor that loosens heterochromatin and facilitates the binding of Klf4 and the expression of epithelial genes in early reprogramming, leading to enhanced mesenchymal-to-epithelial transition. A mutation in the Oct4 linker, L80A, which shows impaired interaction with the BAF complex component Brg1, is inactive in heterochromatin loosening. Oct4-L80A also blocks the binding of Klf4 and retards MET. Finally, vitamin C or Gadd45a could rescue the reprogramming deficiency of Oct4-L80A by enhancing chromatin opening and Klf4 binding. These studies reveal a cooperation between Oct4 and Klf4 at the chromatin level that facilitates MET at the cellular level and shed light into the research of multiple factors in cell fate determination.

Zebrafish cox17 modulates primitive erythropoiesis via regulation of mitochondrial metabolism to facilitate hypoxia tolerance.

Cox17 is required in the assembly of mitochondrial intermembrane space (IMS) and Cu metallization of cytochrome C oxidase (CcO) in mitochondria as well as Cu homeostasis in cells. Cox deficiency is associated with hematopoietic diseases such as tubulopathy and leukodystrophy, but whether and how cox17 functions in hematopoiesis are still unknown. Here, we report the effects of zebrafish cox17 deficiency on primitive erythropoiesis, mitochondrial metabolism, and hypoxia tolerance. Cox17-/- larvae were sensitive to hypoxia stress, with reduced primitive erythropoiesis. Meanwhile, cox17-/- mutants showed a significant reduction in the expression of pivotal transcriptional regulators in erythropoiesis, such as scl, lmo2, and gata1a at 14 h post fertilization (hpf), with expression remaining downregulated for scl but upregulated for lmo2 and gata1a at 24 hpf. Mechanistically, cox17-/- mutants showed impaired mitochondrial metabolism, coupled with a significant decrease in the mitochondrial membrane potential, ATP and SAM content, and the ratio of SAM and SAH. Additionally, disrupting mitochondrial metabolism in wild type (WT) larvae treated with carbonyl cyanide 3-chlorophenylhydrazone (CCCP) could mimic the primitive erythropoiesis defects observed in cox17-/- mutants. Moreover, cox17-/- mutants exhibited significantly downregulated WNT signaling and upregulated ER stress, with a significant reduction of beta-Catenin in gata1a+ cells and of binding enrichment in both scl and lmo2 promoters of the WNT transcriptional factor TCF4. This is the first report on the novel linkage of cox17 deficiency with defective primitive erythropoiesis and reduced hypoxia tolerance. This study has shed light on the potential mechanism by which Cox deficiency, especially cox17 deficiency, induces Cu homeostasis imbalance, leading to hematopoietic diseases.

Transcriptome analysis of response mechanism to Microcystin-LR and microplastics stress in Asian clam (Corbicula fluminea).

In this study, we analyzed the hepatopancreas tissues of Asian Clam (Corbicula fluminea) exposed to three different adverse environmental conditions from the same batch using RNA-seq. The four treatment groups included the Asian Clam group treated with Microcystin-LR (MC), the Microplastics-treated group (MP), the Microcystin-LR and Microplastics-treated group (MP-MC), and the Control group. Our Gene Ontology analysis revealed 19,173 enriched genes, and the Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis identified 345 related pathways. The KEGG pathway analysis demonstrated that the MC vs control group and the MP vs control group were significantly enriched in immune and catabolic pathways such as Antigen processing and presentation, Rheumatoid arthritis, Lysosome pathway, Phagosome pathway, and Autophagy pathway. We also evaluated the effects of Microplastics and Microcystin-LR on the activities of eight antioxidant enzymes and immune enzymes in Asian clams. Our study enriched the genetic resources of Asian clams and provided valuable information for understanding the response mechanism of Asian clams to microplastics and microcystin in the environment, through the identification of differentially expressed genes and related pathway analyses from the large number of transcriptome sequences obtained.

Transcriptomic analysis of the antioxidant responses and immunomodulatory effects of dietary melatonin in red swamp crayfish (Procambarus clarkii).

This study aimed to investigate the effects of dietary melatonin (MT) levels on the antioxidant capacity, immunomodulatory, and transcriptional regulation of red swamp crayfish. Six experimental diets with different levels of MT (0, 22.5, 41.2, 82.7, 165.1, and 329.2 mg/kg diet) were fed to juvenile crayfish for 60 d. The transcriptome data of the control group and the group supplemented with dietary MT at 165.1 mg/kg were obtained using RNA-seq. In total, 3653 differentially expressed genes (2082 up-regulated and 1571 down-regulated) were identified. Pathways and genes related to antioxidant immune and growth performance were verified by qRT-PCR. The total hemocyte count, phagocytosis rate, and respiratory burst were significantly increased in the MT (165.1 mg/kg) group compared to the control group. Analysis of antioxidant immune-related enzymes in the hepatopancreas demonstrated that dietary MT (165.1 mg/kg) significantly increased activities of catalase, superoxide dismutase, glutathione reductase, and glutathione peroxidase and significantly decreased aspartate aminotransferase and alanine aminotransferase activity. At the transcriptional level, dietary MT up-regulated expression levels of genes associated with antioxidant immune and development, which included toll-like receptors, Crustin, C-type lectin, and so on. To conclude, MT could be used as a supplement in crayfish feed to increase immunity and antioxidant capacity and according to the broken line regression, the ideal MT concentration was the 159.02 mg/kg. Overall, this study demonstrates the role of melatonin in the antioxidant responses and immunomodulatory of Procambarus clarkii, laying the foundation for the development of melatonin as a feed additive in the aquaculture of this species.

Downregulation of a mitochondrial micropeptide, MPM, promotes hepatoma metastasis by enhancing mitochondrial complex I activity.

We and others have shown that MPM (micropeptide in mitochondria) regulates myogenic differentiation and muscle development. However, the roles of MPM in cancer development remain unknown. Here we revealed that MPM was downregulated significantly in human hepatocellular carcinoma (HCC) tissues and its decrease was associated with increased metastasis potential and HCC recurrence. Gain- and loss-of-function investigations disclosed that in vitro migration/invasion and in vivo liver/lung metastasis of hepatoma cells were repressed by restoring MPM expression and increased by silencing MPM. Mechanism investigations revealed that MPM interacted with NDUFA7. Mitochondrial complex I activity was inhibited by overexpressing MPM and enhanced by siMPM, and this effect of siMPM was attenuated by knocking down NDUFA7. The NAD+/NADH ratio, which was regulated by complex I, was reduced by MPM but increased by siMPM. Treatment with the NAD+ precursor nicotinamide abrogated the inhibitory effect of MPM on hepatoma cell migration. Further investigations showed that miR-17-5p bound to MPM and inhibited MPM expression. miR-17-5p upregulation was associated with MPM downregulation in HCC tissues. These findings indicate that a decrease in MPM expression may promote hepatoma metastasis by increasing mitochondrial complex I activity and the NAD+/NADH ratio.

Mitolysosome exocytosis: a novel mitochondrial quality control pathway linked with parkinsonism-like symptoms.

Quality control of mitochondria is essential for their homeostasis and function. Light chain 3 (LC3) associated autophagosomes-mediated mitophagy represents a canonical mitochondrial quality control pathway. Alternative quality control processes, such as mitochondrial-derived vesicles (MDVs), have been discovered, but the intact mitochondrial quality control remains unknown. We recently discovered a novel mitolysosome exocytosis mechanism for mitochondrial quality control in flunarizine (FNZ)-induced mitochondria clearance, where autophagosomes are not required, but rather mitochondria are engulfed directly by lysosomes, mediating mitochondrial secretion. As FNZ results in parkinsonism, we propose that excessive mitolysosome exocytosis is the cause.

Distribution and apoptotic function of outer membrane proteins depend on mitochondrial fusion.

Cells deficient in mitochondrial fusion have been shown to have defects linked to the exchange of inner membrane and matrix components. Because outer-mitochondrial membrane (OMM) constituents insert directly from the cytoplasm, a role for fusion in their intermitochondrial transfer was unanticipated. Here, we show that fibroblasts lacking the GTPases responsible for OMM fusion, mitofusins 1 and 2 (MFN1 and MFN2), display more heterogeneous distribution of OMM proteins. Proteins with different modes of OMM association display varying degrees of heterogeneity in Mfn1/2(-/-) cells and different kinetics of transfer during fusion in fusion-competent cells. Proapoptotic Bak exhibits marked heterogeneity, which is normalized upon expression of MFN2. Bak is critical for Bid-induced OMM permeabilization and cytochrome c release, and Mfn1/2(-/-) cells show dysregulation of Bid-dependent apoptotic signaling. Bid sensitivity of Bak-deficient mitochondria is regained upon fusion with Bak-containing mitochondria. Thus, OMM protein distribution depends on mitochondrial fusion and is a locus of apoptotic dysfunction in conditions of fusion deficiency.

Mitochondrial nucleoid in cardiac homeostasis: bidirectional signaling of mitochondria and nucleus in cardiac diseases.

Metabolic function and energy production in eukaryotic cells are regulated by mitochondria, which have been recognized as the intracellular 'powerhouses' of eukaryotic cells for their regulation of cellular homeostasis. Mitochondrial function is important not only in normal developmental and physiological processes, but also in a variety of human pathologies, including cardiac diseases. An emerging topic in the field of cardiovascular medicine is the implication of mitochondrial nucleoid for metabolic reprogramming. This review describes the linear/3D architecture of the mitochondrial nucleoid (e.g., highly organized protein-DNA structure of nucleoid) and how it is regulated by a variety of factors, such as noncoding RNA and its associated R-loop, for metabolic reprogramming in cardiac diseases. In addition, we highlight many of the presently unsolved questions regarding cardiac metabolism in terms of bidirectional signaling of mitochondrial nucleoid and 3D chromatin structure in the nucleus. In particular, we explore novel techniques to dissect the 3D structure of mitochondrial nucleoid and propose new insights into the mitochondrial retrograde signaling, and how it regulates the nuclear (3D) chromatin structures in mitochondrial diseases.

Mutations in C1orf194, encoding a calcium regulator, cause dominant Charcot-Marie-Tooth disease.

Charcot-Marie-Tooth disease is a hereditary motor and sensory neuropathy exhibiting great clinical and genetic heterogeneity. Here, the identification of two heterozygous missense mutations in the C1orf194 gene at 1p21.2-p13.2 with Charcot-Marie-Tooth disease are reported. Specifically, the p.I122N mutation was the cause of an intermediate form of Charcot-Marie-Tooth disease, and the p.K28I missense mutation predominately led to the demyelinating form. Functional studies demonstrated that the p.K28I variant significantly reduced expression of the protein, but the p.I122N variant increased. In addition, the p.I122N mutant protein exhibited the aggregation in neuroblastoma cell lines and the patient's peroneal nerve. Either gain-of-function or partial loss-of-function mutations to C1ORF194 can specify different causal mechanisms responsible for Charcot-Marie-Tooth disease with a wide range of clinical severity. Moreover, a knock-in mouse model confirmed that the C1orf194 missense mutation p.I121N led to impairments in motor and neuromuscular functions, and aberrant myelination and axonal phenotypes. The loss of normal C1ORF194 protein altered intracellular Ca2+ homeostasis and upregulated Ca2+ handling regulatory proteins. These findings describe a novel protein with vital functions in peripheral nervous systems and broaden the causes of Charcot-Marie-Tooth disease, which open new avenues for the diagnosis and treatment of related neuropathies.

HZ-A-005, a potent, selective, and covalent Bruton's tyrosine kinase inhibitor in preclinical development.

Bruton's tyrosine kinase (BTK), a non-receptor tyrosine kinase, is a member of the Tec kinases family and is essential for B cell receptor (BCR) mediated signaling. BTK inhibitors such as ibrutinib hold a prominent role in the treatment of B cell malignancies. Here we disclose a potent, selective, and covalent BTK inhibitor, HZ-A-005, currently in preclinical development. HZ-A-005 demonstrated dose-dependent activity in two xenograft models of lymphoma in vivo. It showed highly favourable safety, pharmacokinetic (PK), and pharmacodynamic (PD) profiles in preclinical studies. On the basis of its potency, selectivity, and covalent mode of inhibition, HZ-A-005 reveals the potential to be a promising BTK inhibitor for a wide range of cancer indications.

Diffraction efficiency evaluation for diamond turning of harmonic diffractive optical elements.

Single point diamond turning is a commonly used method for manufacturing harmonic diffractive optical elements (HDOEs). Diffraction efficiency of HDOEs is sensitive to surface-relief profile errors, and a half-round tool can reduce the profile error obviously. Furthermore, the diamond tools also create surface roughness errors. The two errors will produce shadowing and scattering effects. In this paper, the two kinds of errors, especially the surface roughness, are described accurately. A mathematical model is proposed to reveal the relationship among diffraction efficiency, cutting tool radius, feed rate, microstructure zone period widths, and the refractive index of the substrate material and balance the influence of shadowing and scattering effects. The simulation results show that the model can guide the acquisition of high-precision surface topography and high diffraction efficiency, which improves the imaging quality of the optical system.

Optimization method of tool path generation considering the edge of lenslets for a microlens array in FTS diamond turning.

Shape accuracy is an important parameter for evaluating the quality of microlens arrays. In fast tool servo (FTS) diamond turning, the generation of tool path has a significant influence on shape accuracy. By analyzing the distribution of the cutting points at the edge of the lenslets and the linearization error of the original tool path generated by the constant-angle method for the microlens array, there is overcut at the edge of the lenslets. Previous tool path planning focused on consideration of the entire surface, and the error on the edge of the lens was rarely considered. Therefore, an optimization method of tool path generation based on interpolation of the lens edge is proposed. Compared to the tool path generated by the conventional constant-angle method, the simulation and experimental results show that the proposed method can effectively reduce the overcut of the lens edge.

Infrared Image Super-Resolution Reconstruction Based on Quaternion and High-Order Overlapping Group Sparse Total Variation.

Owing to the limitations of imaging principles and system imaging characteristics, infrared images generally have some shortcomings, such as low resolution, insufficient details, and blurred edges. Therefore, it is of practical significance to improve the quality of infrared images. To make full use of the information on adjacent points, preserve the image structure, and avoid staircase artifacts, this paper proposes a super-resolution reconstruction method for infrared images based on quaternion total variation and high-order overlapping group sparse. The method uses a quaternion total variation method to utilize the correlation between adjacent points to improve image anti-noise ability and reconstruction effect. It uses the sparsity of a higher-order gradient to reconstruct a clear image structure and restore smooth changes. In addition, we performed regularization by using the denoising method, alternating direction method of multipliers, and fast Fourier transform theory to improve the efficiency and robustness of our method. Our experimental results show that this method has excellent performance in objective evaluation and subjective visual effects.

Gadd45a is a heterochromatin relaxer that enhances iPS cell generation.

Reprogramming of somatic cells to induced pluripotent stem cells rewrites the code of cell fate at the chromatin level. Yet, little is known about this process physically. Here, we describe a fluorescence recovery after photobleaching method to assess the dynamics of heterochromatin/euchromatin and show significant heterochromatin loosening at the initial stage of reprogramming. We identify growth arrest and DNA damage-inducible protein a (Gadd45a) as a chromatin relaxer in mouse embryonic fibroblasts, which also enhances somatic cell reprogramming efficiency. We show that residue glycine 39 (G39) in Gadd45a is essential for interacting with core histones, opening chromatin and enhancing reprogramming. We further demonstrate that Gadd45a destabilizes histone-DNA interactions and facilitates the binding of Yamanaka factors to their targets for activation. Our study provides a method to screen factors that impact on chromatin structure in live cells, and identifies Gadd45a as a chromatin relaxer.

Srebp-1 Interacts with c-Myc to Enhance Somatic Cell Reprogramming.

Somatic cell reprogramming is accompanied by changes in lipid metabolism. While attempting to dissect the molecular mechanisms of the lipid metabolic switch during reprogramming, we found that overexpression of sterol regulatory element binding protein-1 (Srebp-1), a transcriptional factor required for lipid homeostasis, enhances reprogramming efficiency, while knockdown or pharmaceutical inhibition of Srebp-1 is inhibitory. Srebp-1 overexpression blocks the formation of partially reprogrammed cells, and functions in the early phase of reprogramming. Furthermore, Srebp-1 functions in nucleus and depends on its transcriptional activity but not its ability to bind the E-box motif and regulation of canonical targets. Mechanistically, Srebp-1 interacts with c-Myc, facilitates its binding to downstream pluripotent targets, strengthens the function of c-Myc in enhancing other Yamanaka factors' binding, and thereby promotes the expression of pluripotent genes. These results elucidate a novel role for Srebp-1 in somatic cell reprogramming and provide insights into understanding the metabolic switch during reprogramming.

Estimation of Human Body Volume (BV) from Anthropometric Measurements Based on Three-Dimensional (3D) Scan Technique.

BACKGROUND: This study aimed to develop estimation formulae for the total human body volume (BV) of adult males using anthropometric measurements based on a three-dimensional (3D) scanning technique. Noninvasive and reliable methods to predict the total BV from anthropometric measurements based on a 3D scan technique were addressed in detail. METHODS: A regression analysis of BV based on four key measurements was conducted for approximately 160 adult male subjects. Eight total models of human BV show that the predicted results fitted by the regression models were highly correlated with the actual BV (p < 0.001). RESULTS: Two metrics, the mean value of the absolute difference between the actual and predicted BV (V error) and the mean value of the ratio between V error and actual BV (RV error), were calculated. The linear model based on human weight was recommended as the most optimal due to its simplicity and high efficiency. CONCLUSIONS: The proposed estimation formulae are valuable for estimating total body volume in circumstances in which traditional underwater weighing or air displacement plethysmography is not applicable or accessible. LEVEL OF EVIDENCE IV: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266.

Valproic acid-induced hepatotoxicity in Alpers syndrome is associated with mitochondrial permeability transition pore opening-dependent apoptotic sensitivity in an induced pluripotent stem cell model.

UNLABELLED: Valproic acid (VPA) is widely used to treat epilepsy, migraine, chronic headache, bipolar disorder, and as adjuvant chemotherapy, but potentially causes idiosyncratic liver injury. Alpers-Huttenlocher syndrome (AHS), a neurometabolic disorder caused by mutations in mitochondrial DNA polymerase gamma (POLG), is associated with an increased risk of developing fatal VPA hepatotoxicity. However, the mechanistic link of this clinical mystery remains unknown. Here, fibroblasts from 2 AHS patients were reprogrammed to induced pluripotent stem cells (iPSCs) and then differentiated to hepatocyte-like cells (AHS iPSCs-Hep). Both AHS iPSCs-Hep are more sensitive to VPA-induced mitochondrial-dependent apoptosis than controls, showing more activated caspase-9 and cytochrome c release. Strikingly, levels of both soluble and oligomeric optic atrophy 1, which together keep cristae junctions tight, are reduced in AHS iPSCs-Hep. Furthermore, POLG mutation cells show reduced POLG expression, mitochondrial DNA (mtDNA) amount, mitochondrial adenosine triphosphate production, as well as abnormal mitochondrial ultrastructure after differentiation to hepatocyte-like cells. Superoxide flashes, spontaneous bursts of superoxide generation, caused by opening of the mitochondrial permeability transition pore (mPTP), occur more frequently in AHS iPSCs-Hep. Moreover, the mPTP inhibitor, cyclosporine A, rescues VPA-induced apoptotic sensitivity in AHS iPSCs-Hep. This result suggests that targeting mPTP opening could be an effective method to prevent hepatotoxicity by VPA in AHS patients. In addition, carnitine or N-acetylcysteine, which has been used in the treatment of VPA-induced hepatotoxicity, is able to rescue VPA-induced apoptotic sensitivity in AHS iPSCs-Hep. CONCLUSION: AHS iPSCs-Hep are more sensitive to the VPA-induced mitochondrial-dependent apoptotic pathway, and this effect is mediated by mPTP opening. Toxicity models in genetic diseases using iPSCs enable the evaluation of drugs for therapeutic targets.

Electrophilic Fluorination of Secondary Phosphine Oxides and Its Application to P-O Bond Construction.

A novel and efficient electrophilic fluorination of secondary phosphine oxides with Selectfluor has been achieved. This transformation provides direct access to phosphoric fluorides in up to 92% yield under mild conditions. In addition, P-O bond construction via a one-pot coupling process of secondary phosphine oxides with water or alcohols in the presence of Selectfluor leads to the formation of phosphinic acids or phosphinates in up to 96% yield.