PCYT1A deficiency disturbs fatty acid metabolism and induces ferroptosis in the mouse retina.

BACKGROUND: Inherited retinal dystrophies (IRDs) are a group of debilitating visual disorders characterized by the progressive degeneration of photoreceptors, which ultimately lead to blindness. Among the causes of this condition, mutations in the PCYT1A gene, which encodes the rate-limiting enzyme responsible for phosphatidylcholine (PC) de novo synthesis via the Kennedy pathway, have been identified. However, the precise mechanisms underlying the association between PCYT1A mutations and IRDs remain unclear. To address this knowledge gap, we focused on elucidating the functions of PCYT1A in the retina. RESULTS: We found that PCYT1A is highly expressed in Müller glial (MG) cells in the inner nuclear layer (INL) of the retina. Subsequently, we generated a retina-specific knockout mouse model in which the Pcyt1a gene was targeted (Pcyt1a-RKO or RKO mice) to investigate the molecular mechanisms underlying IRDs caused by PCYT1A mutations. Our findings revealed that the deletion of Pcyt1a resulted in retinal degenerative phenotypes, including reduced scotopic electroretinogram (ERG) responses and progressive degeneration of photoreceptor cells, accompanied by loss of cells in the INL. Furthermore, through proteomic and bioinformatic analyses, we identified dysregulated retinal fatty acid metabolism and activation of the ferroptosis signalling pathway in RKO mice. Importantly, we found that PCYT1A deficiency did not lead to an overall reduction in PC synthesis within the retina. Instead, this deficiency appeared to disrupt free fatty acid metabolism and ultimately trigger ferroptosis. CONCLUSIONS: This study reveals a novel mechanism by which mutations in PCYT1A contribute to the development of IRDs, shedding light on the interplay between fatty acid metabolism and retinal degenerative diseases, and provides new insights into the treatment of IRDs.

KOtBu/DMF-Mediated Hydroalkylation of Alkenes via Benzylic C-H Bond Activation.

Catalytic hydroalkylation reaction of alkenes with benzylic hydrocarbons involving t-BuOK/DMF-mediated benzylic C-H bond activation is demonstrated. This direct and operational simple protocol affords a rapid and reliable access to a wide scope of benzylic compounds in good-to-excellent yields. The benzylic C-H's of either activated diarylmethanes (pKa ∼ 32.2) and benzyl thioethers (pKa ∼ 30.8) or inert alkylbenzenes could all act as useful synthetic platforms to be conveniently alkylated under mild reaction conditions.

Ultrapermeable Gel Membranes Enabling Superior Carbon Capture.

Membrane technology is rapidly gaining broad attraction as a viable alternative for carbon capture to mitigate increasingly severe global warming. Emerging CO2 -philic membranes have become crucial players in efficiently separating CO2 from light gases, leveraging their exceptional solubility-selectivity characteristics. However, economic and widespread deployment is greatly dependent on the boosted performance of advanced membrane materials for carbon capture. Here, we design a unique gel membrane composed of CO2 -philic molecules for accelerating CO2 transportation over other gases for ultrapermeable carbon capture. The molecular design of such soft membranes amalgamates the advantageous traits of augmented permeation akin to liquid membranes and operational stability akin to solid membranes, effectively altering the membrane's free volume characteristics validated by both experiments and molecular dynamics simulation. Surprisingly, gas diffusion through the free-volume-tuned gel membrane undergoes a 9-fold improvement without compromising the separation factor for the superior solubility selectivity of CO2 -philic materials, and CO2 permeability achieves a groundbreaking record of 5608 Barrer surpassing the capabilities of nonfacilitated CO2 separation materials and exceeding the upper bound line established in 2019 even by leading-edge porous polymer materials. Our designed gel membrane can maintain exceptional separation performance during prolonged operation, enabling the unparalleled potential of solubility-selective next-generation materials towards sustainable carbon capture.

Understanding the Streptomyces albulus response to low-pH stress at the interface of physiology and transcriptomics.

Streptomyces albulus is a well-established cell factory for ε-poly-L-lysine (ε-PL) production. It has been reported that ε-PL biosynthesis is strictly regulated by pH and that ε-PL can accumulate at approximately pH 4.0, which is outside of the general pH range for natural product production by Streptomyces species. However, how S. albulus responds to low pH is not clear. In this study, we attempted to explore the response of S. albulus to low-pH stress at the physiological and global gene transcription levels. At the physiological level, S. albulus maintained intracellular pH homeostasis at ~pH 7.5, increased the unsaturated fatty acid ratio, extended the fatty acid chain length, enhanced ATP accumulation, increased H+-ATPase activity, and accumulated the basic amino acids L-lysine and L-arginine. At the global gene transcription level, carbohydrate metabolism, oxidative phosphorylation, macromolecule protection and repair, and the acid tolerance system were found to be involved in combating low-pH stress. Finally, we preliminarily evaluated the effect of the acid tolerance system and cell membrane fatty acid synthesis on low-pH tolerance via gene manipulation. This work provides new insight into the adaptation mechanism of Streptomyces to low-pH stress and a new opportunity for constructing robust S. albulus strains for ε-PL production. KEY POINTS: • S. albulus consistently remained pH i at ~7.4 regardless of the environmental pH. • S. albulus combats low-pH stress by modulating lipid composition of cell membrane. • Overexpression of cfa in S. albulus could improve low-pH tolerance and ɛ-PL titer.

Dysregulated m6A modification promotes lipogenesis and development of non-alcoholic fatty liver disease and hepatocellular carcinoma.

Type 2 diabetes mellitus (DM2) is associated closely with non-alcoholic fatty liver disease (NAFLD) by affecting lipid metabolism, which may lead to non-alcoholic steatohepatitis (NASH), fibrosis, and hepatocellular carcinoma (HCC). N6-methyladenosine (m6A) RNA methylation is an important epigenetic regulation for gene expression and is related to HCC development. We developed a new NAFLD model oriented from DM2 mouse, which spontaneously progressed to histological features of NASH, fibrosis, and HCC with high incidence. By RNA sequencing, protein expression and methylated RNA immunoprecipitation (MeRIP)-qPCR analysis, we found that enhanced expression of ACLY and SCD1 in this NAFLD model and human HCC samples was due to excessive m6A modification, but not elevation of mature SREBP1. Moreover, targeting METTL3/14 in vitro increases protein level of ACLY and SCD1 as well as triglyceride and cholesterol production and accumulation of lipid droplets. m6A sequencing analysis revealed that overexpressed METTL14 binds to mRNA of ACLY and SCD1 and alters their expression pattern. Our findings demonstrate a new NAFLD mouse model that provides a study platform for DM2-related NAFLD and reveals a unique epitranscriptional regulating mechanism for lipid metabolism via m6A-modified protein expression of ACLY and SCD1.

CCHCR1-astrin interaction promotes centriole duplication through recruitment of CEP72.

BACKGROUND: The centrosome is one of the most important non-membranous organelles regulating microtubule organization and progression of cell mitosis. The coiled-coil alpha-helical rod protein 1 (CCHCR1, also known as HCR) gene is considered to be a psoriasis susceptibility gene, and the protein is suggested to be localized to the P-bodies and centrosomes in mammalian cells. However, the exact cellular function of HCR and its potential regulatory role in the centrosomes remain unexplored. RESULTS: We found that HCR interacts directly with astrin, a key factor in centrosome maturation and mitosis. Immunoprecipitation assays showed that the coiled-coil region present in the C-terminus of HCR and astrin respectively mediated the interaction between them. Astrin not only recruits HCR to the centrosome, but also protects HCR from ubiquitin-proteasome-mediated degradation. In addition, depletion of either HCR or astrin significantly reduced centrosome localization of CEP72 and subsequent MCPH proteins, including CEP152, CDK5RAP2, and CEP63. The absence of HCR also caused centriole duplication defects and mitotic errors, resulting in multipolar spindle formation, genomic instability, and DNA damage. CONCLUSION: We conclude that HCR is localized and stabilized at the centrosome by directly binding to astrin. HCR are required for the centrosomal recruitment of MCPH proteins and centriolar duplication. Both HCR and astrin play key roles in keeping normal microtubule assembly and maintaining genomic stability.

Trichosanthin Promotes Anti-Tumor Immunity through Mediating Chemokines and Granzyme B Secretion in Hepatocellular Carcinoma.

Trichosanthin (TCS) is a type I ribosome-inactivating protein extracted from the tuberous root of the plant Trichosanthes. TCS shows promising potential in clinical drug abortion, anti-tumor and immunological regulation. However, the molecular mechanisms of its anti-tumor and immune regulation properties are still not well discovered. In the present study, we investigated the anti-tumor activity of TCS in hepatocellular carcinoma (HCC), both in vitro and in vivo. Both HCC cell lines and xenograft tumor tissues showed considerable growth inhibition after they were treated with TCS. TCS provoked caspase-mediated apoptosis in HCC cells and xenograft tumor tissues. The recruitment of CD8+ T cells to HCC tissues and the expression of chemokines, CCL2 and CCL22, were promoted upon TCS treatment. In addition, TCS induced an upregulation of Granzyme B (GrzB), TNF-α and IFN-γ in HCC tissues, which are the major cytotoxic mediators produced by T cells. Furthermore, TCS also resulted in an increase of mannose-6-phosphate receptor (M6PR), the major receptor of GrzB, in HCC tissues. In summary, these results suggest that TCS perhaps increases T-cell immunity via promoting the secretion of chemokines and accelerating the entry of GrzB to HCC cells, which highlights the potential role of TCS in anti-tumor immunotherapy.

Upgrading Octane Number of Naphtha by a Robust and Easily Attainable Metal-Organic Framework through Selective Molecular Sieving of Alkane Isomers.

The separation of alkanes, particularly monobranched and dibranched isomers, is of paramount importance in the petrochemical industry for optimizing the feedstock of ethylene production as well as for upgrading the octane number of gasoline. Here, we report the full separation of linear/monobranched alkanes from their dibranched isomers by a robust and easily scalable metal-organic framework material, Co3 (HCOO)6 . The compound completely excludes dibranched alkanes but adsorbs their linear and monobranched isomers, as evidenced by single-component and multicomponent adsorption measurements. More importantly, the material exhibits excellent performance in separating naphtha and is capable of providing high quality feedstock for the production of ethylene and gasoline components with high octane number, making it a promising candidate for naphtha separation in petrochemical industry.

Mechanisms of response to pH shock in microbial fermentation.

The following review highlights pH shock, a novel environmental factor, as a tool for the improvement of fermentation production. The aim of this review is to introduce some recent original studies on the enhancement of microbial fermentation production by pH shock. Another purpose of this review is to improve the understanding of the processes that underlie physiological and genetic differences, which will facilitate future research on the improvement of fermentation production and reveal the associated molecular mechanisms. This understanding will simultaneously promote the application of this strategy to other microbial fermentation systems. Furthermore, improvement of the cellular tolerance of genetically engineered bacteria can also be a new field of research in the future to enhance fermentation production.

Morphological and Compositional Analysis of Two Walnut (Juglans regia L.) Cultivars Growing in China.

Two selected walnut cultivars (Xiangling and Jizhaomian) growing in China were analyzed in terms of proximate and mineral composition, fatty acid and amino acid profile. According to the higher kernel rate (61.22%), thinner shell (1.03 mm), higher content of fat (66.93%), protein (20.97%), essential amino acids (29.31% of total amino acids) and minerals such as manganese, zinc and copper, Xiangling would be the more nutritive cultivar with more commercial value. However, Jizhaomian would be the more healthful cultivar based on the higher content of polyunsaturated fatty acids (79.39% of total fatty acids), and it would be more sensitive to rancidity. Jizhaomian also showed higher content in potassium, calcium, magnesium and iron. Genotype is the major source of variability in morphology and chemical compositions. Regardless of the cultivar, consumption of walnuts is desirably encouraged, since all of them contain compounds potentially beneficial to health.

The Skin Bridge Is More Important as an Additional Venous Draining Route in a Perforator-Plus Flap.

BACKGROUND: The skin bridge in the perforator-plus flap is considered as an additional source for arterial input and venous drainage apart from the perforator. However, its exact role requires further elucidation. MATERIALS AND METHODS: Forty rats that underwent flap elevation with a size of 9 × 3 cm on the dorsum were evenly divided into a perforators-intact group with an intact vascular pedicle, an artery-deficient group with the artery ligated, a vein-deficient group with the vein ligated, and a perforators-deficient group with both vessels ligated. The blood perfusion was measured using a laser Doppler flowmeter. On the seventh day, the necrosis rate of the flaps was calculated and the diameter of vessels in the skin bridge was measured. RESULTS: The perfusion pattern was similar between the perforators-intact group and vein-deficient group, as well as between the perforators-deficient group and artery-deficient group. The blood perfusion was much more robust in the perforators-intact and vein-deficient groups. The necrosis rate in the perforators-deficient group (26 ± 1%) was not significantly different from that in the artery-deficient group (29 ± 1%), both of which was significantly larger than that in the perforator-intact (11 ± 3%) and vein-deficient groups (12 ± 4%) (P ˂ 0.001). The venous network of the skin base in the vein-deficient and perforators-deficient groups dilated dramatically, whereas the arterial network in the artery-deficient and perforators-deficient groups had a very modest expansion. CONCLUSIONS: The skin base in a perforator-plus flap is much more important as an additional route for vein drainage than for arterial input.

Understanding high ε-poly-L-lysine production by Streptomyces albulus using pH shock strategy in the level of transcriptomics.

ε-Poly-L-lysine (ε-PL) is a natural food preservative, which exhibits antimicrobial activity against a wide spectra of microorganisms. The production of ε-PL was significantly enhanced by pH shock in our previous study, but the underlying mechanism is poorly understood. According to transcriptional and physiological analyses in this study, the mprA/B and pepD signal transduction system was first proved to be presented and activated in Streptomyces albulus M-Z18 by pH shock, which positively regulated the transcription of ε-PL synthetase (Pls) gene and enhanced the Pls activity during fermentation. Furthermore, pH shock changed the ratio of unsaturation to saturation fatty acid in the membrane through up-regulating the transcription of fatty acid desaturase genes (SAZ_RS14940, SAZ_RS14945). In addition, pH shock also enhanced the transcription of cytochrome c oxidase (SAZ_RS15070, SAZ_RS15075), ferredoxin reductase (SAZ_RS34975) and iron sulfur protein (SAZ_RS31410) genes, and finally resulted in the improvement of cell respiratory activity. As a result, pH shock was considered to influence a wide range of proteins including regulators, fatty acid desaturase, respiratory chain component, and ATP-binding cassette transporter during fermentation. These combined influences might contribute to enhanced ε-PL productivity with pH shock.

P2X7 receptor: A receptor closely linked with sepsis-associated encephalopathy.

Sepsis is defined as a dysregulated host response to infection resulting in life-threatening organ dysfunction. Sepsis-associated encephalopathy (SAE) is the main manifestation of sepsis. Inflammation, peroxidation stress injury, and apoptosis are the main factors involved in the pathogenesis of SAE. A growing body of evidence has proved that P2X7 receptor (P2X7R), a cationic channel receptor that is widely distributed in the body, plays a major role in the occurrence and development of inflammatory injury. Therefore, this review mainly describes the activation of P2X7R in sepsis, which leads to the recruitment of inflammatory cells to the cerebral vasculature, the destruction of the blood-brain barrier, the activation of microglial cells in the brain, the apoptosis of brain cells, and other damage processes. This review also illustrates the potential therapeutic value of P2X7R inhibition in SAE.

Restoring the Function of Thalamocortical Circuit Through Correcting Thalamic Kv3.2 Channelopathy Normalizes Fear Extinction Impairments in a PTSD Mouse Model.

Impaired extinction of fear memory is one of the most common symptoms in post-traumatic stress disorder (PTSD), with limited therapeutic strategies due to the poor understanding of its underlying neural substrates. In this study, functional screening is performed and identified hyperactivity in the mediodorsal thalamic nucleus (MD) during fear extinction. Furthermore, the encoding patterns of the hyperactivated MD is investigated during persistent fear responses using multiple machine learning algorithms. The anterior cingulate cortex (ACC) is also identified as a functional downstream region of the MD that mediates the extinction of fear memory. The thalamocortical circuit is comprehensively analyzed and found that the MD-ACC parvalbumin interneurons circuit is preferentially enhanced in PTSD mice, disrupting the local excitatory and inhibitory balance. It is found that decreased phosphorylation of the Kv3.2 channel contributed to the hyperactivated MD, primarily to the malfunctioning thalamocortical circuit. Using a lipid nanoparticle-based RNA therapy strategy, channelopathy is corrected via a methoxylated siRNA targeting the protein phosphatase 6 catalytic subunit and restored fear memory extinction in PTSD mice. These findings highlight the function of the thalamocortical circuit in PTSD-related impaired extinction of fear memory and provide therapeutic insights into Kv3.2-targeted RNA therapy for PTSD.

Connecting the Dots: The Cerebral Lymphatic System as a Bridge Between the Central Nervous System and Peripheral System in Health and Disease.

As a recently discovered waste removal system in the brain, cerebral lymphatic system is thought to play an important role in regulating the homeostasis of the central nervous system. Currently, more and more attention is being focused on the cerebral lymphatic system. Further understanding of the structural and functional characteristics of cerebral lymphatic system is essential to better understand the pathogenesis of diseases and to explore therapeutic approaches. In this review, we summarize the structural components and functional characteristics of cerebral lymphatic system. More importantly, it is closely associated with peripheral system diseases in the gastrointestinal tract, liver, and kidney. However, there is still a gap in the study of the cerebral lymphatic system. However, we believe that it is a critical mediator of the interactions between the central nervous system and the peripheral system.

Programmable supramolecular chirality in non-equilibrium systems affording a multistate chiroptical switch.

The dynamic regulation of supramolecular chirality in non-equilibrium systems can provide valuable insights into molecular self-assembly in living systems. Herein, we demonstrate the use of chemical fuels for regulating self-assembly pathway, which thereby controls the supramolecular chirality of assembly in non-equilibrium systems. Depending on the nature of different fuel acids, the system shows pathway-dependent non-equilibrium self-assembly, resulting in either dynamic self-assembly with transient supramolecular chirality or kinetically trapped self-assembly with inverse supramolecular chirality. More importantly, successive conducting of chemical-fueled process and thermal annealing process allows for the sequential programmability of the supramolecular chirality between four different chiral hydrogels, affording a new example of a multistate supramolecular chiroptical switch that can be recycled multiple times. The current finding sheds new light on the design of future supramolecular chiral materials, offering access to alternative self-assembly pathways and kinetically controlled non-equilibrium states.

Deletion of Emc1 in photoreceptor cells causes retinal degeneration in mice.

The endoplasmic reticulum membrane protein complex (EMC) plays a critical role in the synthesis of multipass membrane proteins. Genetic studies indicated that mutations in EMC1 gene were associated with retinal degeneration diseases; however, the role of EMC1 in photoreceptor has not been confirmed. Here, we show that Emc1 ablation in the photoreceptor cells of mice recapitulated the retinitis pigmentosa phenotypes, including an attenuated scotopic electroretinogram response and the progressive degeneration of rod cells and cone cells. Histopathological examination of tissues from rod-specific Emc1 knockout mice revealed mislocalized rhodopsin and irregularly arranged cone cells at the age of 2 months. Further immunoblotting analysis revealed decreased levels of membrane proteins and endoplasmic reticulum chaperones in 1-month-old rod-specific Emc1 knockout mice retinae, and this led us to speculate that the loss of membrane proteins is the main cause of the degeneration of photoreceptors. EMC1 most likely regulated the membrane protein levels at an earlier step in the biosynthetic process before the proteins translocated into the endoplasmic reticulum. The present study demonstrates the essential roles of Emc1 in photoreceptor cells, and reveals the mechanism through which EMC1 mutations are linked to retinitis pigmentosa.

Aerobic Exercise Ameliorates Liver Injury in Db/Db Mice by Attenuating Oxidative Stress, Apoptosis and Inflammation Through the Nrf2 and JAK2/STAT3 Signalling Pathways.

Objective: Diabetes mellitus (DM) implicates oxidative stress, apoptosis, and inflammation, all of which may contribute liver injury. Aerobic exercise is assured to positively regulate metabolism in the liver. This project was designed to investigate whether and how aerobic exercise improves DM-induced liver injury. Methods: Seven-week-old male db/db mice and age-matched m/m mice were randomly divided into a rest control group or a group that received 12 weeks of aerobic exercise by treadmill training (10 m/min). Haematoxylin and eosin (HE) staining, electron microscopy, Oil Red O staining and TUNEL assays were used to evaluate the histopathological changes in mouse liver. The serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), triglyceride (TRIG), cholesterol (CHOL) were analyzed by serum biochemical analysis. Interleukin-6 (IL-6), tumour necrosis factor-α (TNF-α), and tissue levels of malondialdehyde (MDA) and superoxide dismutase (SOD) were analyzed via ELISA. Nuclear factor E2-associated factor-2 (Nrf2), nuclear factor κB (NF-κB) and JAK2/STAT3 pathway-related proteins were measured by immunofluorescence, Western blotting and q-PCR. F4/80 expression in liver tissues was assessed by immunohistochemistry. Results: In diabetic mice, exercise training significantly decreased the levels of serum TRIG, CHOL, IL-6, TNF-α, ALT and AST; prevented weight gain, hyperglycaemia, and impaired glucose and insulin tolerance. Morphologically, exercise mitigated the diabetes-induced increase in liver tissue microvesicles, inflammatory cells, F4/80 (macrophage marker) levels, and TUNEL-positive cells. In addition, exercise reduced the apoptosis index, which is consistent with the results for caspase-3 and Bax. Additionally, exercise significantly increased SOD activity, decreased MDA levels, activated Nrf2 and decreased the expression of NF-kB, phosphorylated JAK2 and STAT3 proteins in the livers of diabetic mice. Conclusion: This study demonstrated that aerobic exercise reversed liver dysfunction in db/db mice with T2DM by reducing oxidative stress, apoptosis and inflammation, possibly by enhancing Nrf2 expression and inhibiting the JAK2/STAT3 cascade response.

A Notch signaling-related lncRNA signature for predicting prognosis and therapeutic response in clear cell renal cell carcinoma.

Increasing evidence has confirmed the vital role of Notch signaling in the tumorigenesis of clear cell renal cell carcinoma (ccRCC). The underlying function of long non-coding RNA (lncRNA) related to Notch signaling in ccRCC remains unclear. In present study, the prognostic value and therapeutic strategy of Notch signaling-related lncRNA are comprehensively explored in ccRCC. In total, we acquired 1422 NSRlncRNAs, of which 41 lncRNAs were identified the key NSRlncRNAs associated with the occurrence of ccRCC. The prognostic signature containing five NSRlncRNAs (AC092611.2, NNT-AS1, AGAP2-AS1, AC147651.3, and AC007406.3) was established and validated, and the ccRCC patients were clustered into the high- and low-risk groups. The overall survival of patients in the low-risk group were much more favorable than those in the high-risk group. Multivariate Cox regression analysis indicated that the risk score was an independent prognostic biomarker. Based on the risk score and clinical variables, a nomogram for predicting prognosis of ccRCC patients was constructed, and the calibration curves and DCA curves showed the superior predictive ability of nomogram. The risk score was correlated with immune cell infiltration, targeted therapy or chemotherapy sensitivity, and multiple oncogenic pathways. Additionally, consensus clustering analysis stratified the ccRCC patients into four clusters with obvious different outcomes, immune microenvironments, and expression of immune checkpoints. The constructed NSRlncRNA-based signature might serve as a potential biomarker for predicting prognosis and response to immunotherapy or targeted therapy in patients with ccRCC.