GRD-1/PTR-11, the C. elegans hedgehog/patched-like morphogen-receptor pair, modulates developmental rate.

Both hedgehog (Hh) and target of rapamycin complex 2 (TORC2) are central, evolutionarily conserved signaling pathways that regulate development and metabolism. In C. elegans, loss of the essential TORC2 component RICTOR (rict-1) causes delayed development, shortened lifespan, reduced brood, small size and increased fat. Here, we report that knockdown of both the hedgehog-related morphogen grd-1 and its patched-related receptor ptr-11 rescues delayed development in TORC2 loss-of-function mutants, and grd-1 and ptr-11 overexpression delays wild-type development to a similar level to that in TORC2 loss-of-function animals. These findings potentially indicate an unexpected role for grd-1 and ptr-11 in slowing developmental rate downstream of a nutrient-sensing pathway. Furthermore, we implicate the chronic stress transcription factor pqm-1 as a key transcriptional effector in this slowing of whole-organism growth by grd-1 and ptr-11. We propose that TORC2, grd-1 and ptr-11 may act linearly or converge on pqm-1 to delay organismal development.

Metformin inactivates the cGAS-STING pathway through autophagy and suppresses senescence in nucleus pulposus cells.

Intervertebral disc degeneration (IVDD) is a complex process involving many factors, among which excessive senescence of nucleus pulposus cells is considered to be the main factor. Our previous study found that metformin can inhibit senescence in nucleus pulposus cells; however, the mechanism of such an action was still largely unknown. In the current study, we found that metformin inactivates the cGAS-STING pathway during oxidative stress. Furthermore, knockdown of STING (also known as STING1) suppresses senescence, indicating that metformin might exert its effect through the cGAS-STING pathway. Damaged DNA is a major inducer of the activation of the cGAS-STING pathway. Mechanistically, our study showed that DNA damage was reduced during metformin treatment; however, suppression of autophagy by 3-methyladenine (3-MA) treatment compromised the effect of metformin on DNA damage. In vivo studies also showed that 3-MA might diminish the therapeutic effect of metformin on IVDD. Taken together, our results reveal that metformin may suppress senescence via inactivating the cGAS-STING pathway through autophagy, implying a new application for metformin in cGAS-STING pathway-related diseases.

Dorsoventral hippocampus distinctly modulates visceral sensitivity and anxiety behaviors in male IBS-like rats.

Accumulating evidences suggest dysfunctions in the hippocampus are associated with chronic pain. Nevertheless, the role of hippocampal circuitry in pain memories and emotional responses is not yet fully understood. In this study, we utilized a comprehensive approach that combined electromyography (EMG), photochemical genetic techniques, and anxiety-related behavioral paradigms to investigate the involvement of dorsal hippocampus (DH) and ventral hippocampus (VH) in visceral sensitivity and anxiety behaviors in male rats. Our results demonstrated that IBS-like rats exhibited comorbid visceral hypersensitivity and anxiety, along with the number of activated neurons in the VH was higher than that in the DH. Manipulation of glutamatergic neurons in the hippocampus was identified as a crucial mechanism underlying the mediation of both visceral sensitivity and anxiety behaviors. Specifically, optogenetic activation of the DH induced both visceral hypersensitivity and anxiety, while activation of the VH induced anxiety but did not affect visceral sensitivity. Conversely, chemogenetic inhibition of the DH reduced both visceral hypersensitivity and anxiety, whereas inhibition of the VH alleviated anxiety but did not alleviate visceral hypersensitivity in IBS-like rats. Our study highlights the important role of early life stress in inducing visceral hypersensitivity and anxiety, and further elucidates the distinct functional contributions of the DH and VH to these behavioral changes. These findings provide a theoretical basis for the diagnosis and treatment of IBS, and suggest that targeting specific hippocampal neuron subtypes may represent a promising therapeutic approach.

SNX27-FERM-SNX1 complex structure rationalizes divergent trafficking pathways by SNX17 and SNX27.

The molecular events that determine the recycling versus degradation fates of internalized membrane proteins remain poorly understood. Two of the three members of the SNX-FERM family, SNX17 and SNX31, utilize their FERM domain to mediate endocytic trafficking of cargo proteins harboring the NPxY/NxxY motif. In contrast, SNX27 does not recycle NPxY/NxxY-containing cargo but instead recycles cargo containing PDZ-binding motifs via its PDZ domain. The underlying mechanism governing this divergence in FERM domain binding is poorly understood. Here, we report that the FERM domain of SNX27 is functionally distinct from SNX17 and interacts with a novel DLF motif localized within the N terminus of SNX1/2 instead of the NPxY/NxxY motif in cargo proteins. The SNX27-FERM-SNX1 complex structure reveals that the DLF motif of SNX1 binds to a hydrophobic cave surrounded by positively charged residues on the surface of SNX27. The interaction between SNX27 and SNX1/2 is critical for efficient SNX27 recruitment to endosomes and endocytic recycling of multiple cargoes. Finally, we show that the interaction between SNX27 and SNX1/2 is critical for brain development in zebrafish. Altogether, our study solves a long-standing puzzle in the field and suggests that SNX27 and SNX17 mediate endocytic recycling through fundamentally distinct mechanisms.

Magnetoelectric Sensor Operating in d15 Thickness-Shear Mode for High-Frequency Current Detection.

For the application of high-frequency current detection in power systems, such as very fast transient current, lightning current, partial discharge pulse current, etc., current sensors with a quick response are indispensable. Here, we propose a high-frequency magnetoelectric current sensor, which consists of a PZT piezoelectric ceramic and Metglas amorphous alloy. The proposed sensor is designed to work under d15 thickness-shear mode, with the resonant frequency around 1.029 MHz. Furthermore, the proposed sensor is fabricated as a high-frequency magnetoelectric current sensor. A comparative experiment is carried out between the tunnel magnetoresistance sensor and the magnetoelectric sensor, in the aspect of high-frequency current detection up to 3 MHz. Our experimental results demonstrate that the d15 thickness-shear mode magnetoelectric sensor has great potential for high-frequency current detection in smart grids.

Rearrangement of Arylsulfamates and Sulfates to Para-Sulfonyl Anilines and Phenols.

The C(sp2)-aryl sulfonate functional group is found in bioactive molecules, but their synthesis can involve extreme temperatures (>190 °C or flash vacuum pyrolysis) and strongly acidic reaction conditions. Inspired by the 1917 Tyrer industrial process for a sulfa dye that involved an aniline N(sp2)-SO3 intermediate en route to a C(sp2)-SO3 rearranged product, we investigated tributylsulfoammonium betaine (TBSAB) as a milder N-sulfamation to C-sulfonate relay reagent. Initial investigations of a stepwise route involving TBSAB on selected anilines at room temperature enabled the isolation of N(sp2)-sulfamate. Subsequent thermal rearrangement demonstrated the intermediary of a sulfamate en route to the sulfonate; however, it was low-yielding. Investigation of the N-sulfamate to C--sulfonate mechanism through control experiments with variation at the heteroatom positions and kinetic isotope experiments (KIEH/D) confirmed the formation of a key N(sp2)-SO3 intermediate and further confirmed an intermolecular mechanism. Furthermore, compounds without an accessible nitrogen (or oxygen) lone pair did not undergo sulfamation- (or sulfation) -to-sulfonation under these conditions. A one-pot sulfamation and thermal sulfonation reaction was ultimately developed and explored on a range of aniline and heterocyclic scaffolds with high conversions, including N(sp2)-sulfamates (O(sp2)-sulfates) and C(sp2)-sulfonates, in up to 99 and 80% (and 88% for a phenolic example) isolated yield, respectively. Encouragingly, the ability to modulate the ortho-para selectivity of the products obtained was observed under thermal control. A sulfonated analog of the intravenous anesthetic propofol was isolated (88% yield), demonstrating a proof-of-concept modification of a licensed drug alongside a range of nitrogen- and sulfur-containing heterocyclic fragments used in drug discovery.

A General Method to Access Underexplored Ylideneamino Sulfates as Interrupted Beckmann-Type Rearrangement Intermediates.

The Beckmann rearrangement of ketoximes to their corresponding amides, using a Brønsted acid-mediated fragmentation and migration sequence, has found wide-spread industrial application. We postulated that the development of a methodology to access ylideneamino sulfates using tributylsulfoammonium betaine (TBSAB) would afford isolable Beckmann-type intermediates and competent partners for subsequent rearrangement cascades. The ylideneamino sulfates generated, isolated as their tributylammonium salts, are sufficiently activated to undergo Beckmann rearrangement without additional reagent activation. The generation of sulfuric acid in situ from the ylideneamino sulfate giving rise to a routine Beckmann rearrangement and additional amide bond cleavage to the corresponding aniline was detrimental to reaction success. The screening of bases revealed inexpensive sodium bicarbonate to be an effective additive to prevent classic Brønsted acid-mediated fragmentation and achieve optimal conversions of up to 99%.

Synthesis and Reactivity of Ruthenium(BINAP)(PPh3).

Ru(BINAP)(PPh3)HCl cleanly reacts with LiCH2TMS to give Ru(BINAP)(PPh3) (1) that has been fully characterized, including by X-ray diffraction (BINAP and TMS stand for (2,2'-bis(diphenylphosphino)-1,1'-binaphthyl and trimethylsilyl respectively). In sharp contrast with other carbonyl-free phosphine complexes of Ru(0), 1 demonstrates a strikingly high thermal stability and no propensity for intramolecular C-H activation (cyclometalation). Yet 1 coordinates acetonitrile and readily exchanges its PPh3 ligand with alkenes and dienes, thus behaving like a "masked" 16-e Ru(0) species. Electron-poor alkenes coordinate more readily than electron-rich ones, which testifies for the nucleophilic character of the Ru(0)-BINAP fragment. While being thermally stable, 1 is highly reactive and is capable of activating C-H and N-H bonds, and even of cleaving an inert N-Et bond. The combination of high reactivity and stability originates from the P,arene-chelation by the BINAP ligand, i.e., the coordinated π-arene stabilizes Ru(0) to prevent cyclometalation, yet it can slide upon substrate coordination, thereby enabling a variety of inert bond activation reactions to occur under mild conditions.

The Effect of Terbinafine and Its Ionic Salts on Certain Fungal Plant Pathogens.

Terbinafine, an inhibitor of squalene epoxidase in ergosterol biosynthesis, is chiefly utilized as an antifungal medication with potential uses in pesticide applications. This study explores the fungicidal efficacy of terbinafine against prevalent plant pathogens and confirms its effectiveness. To augment its water solubility, five ionic salts of terbinafine were synthesized by pairing them with organic acids. Among these salts, TIS 5 delivered the most impressive results, amplifying the water solubility of terbinafine by three orders of magnitude and lessening its surface tension to facilitate better dispersion during spraying. The in vivo experiments on cherry tomatoes showed that TIS 5 had a superior therapeutic activity compared to its parent compound and two commonly used broad-spectrum fungicides, pyraclostrobin and carbendazim. The results highlight the potential of terbinafine and its ionic salts, particularly TIS 5, for use as fungicides in agriculture due to their synergistic effects with furan-2-carboxylate.

Methyltransferase-like 3 modulates visceral hypersensitivity through regulating the nuclear export of circKcnk9 in YTHDC1-dependent manner.

Background: Accumulating evidence shows that N6-methyladenosine (m6A) modulators contribute to the process of chronic pain. However, the exact mechanisms of m6A writers involved in visceral hypersensitivity of Irritable bowel syndrome (IBS) remain unclear. This article aimed to reveal a new mechanism for the progression of IBS. Methods: The IBS-like model was established by neonatal colorectal distention (CRD). The relationship between m6A and circKcnk9 was analyzed by bioinformatics, immunofluorescence and RNA fluorescence in situ hybridization (FISH) assays. Visceral hypersensitivity was assessed based on the electromyography (EMG) response of the abdominal external oblique muscle to CRD. In vivo and in vitro studies (including EMG stereotactic infusion, Western blot and qRT-PCR) were utilized to explore the biological functions of related indicators. The bioinformatics, RIP experiments and RNA pull-down assays were used to explore the potential molecular mechanisms. Results: We identified that neonatal CRD increased the level of the m6A via methyltransferase-like 3 (METTL3) in the hippocampal neurons. Subsequently, knockdown of METTL3 could alleviate visceral hypersensitivity in IBS-like rats. By contrast, overexpression of METTL3 could induce visceral hypersensitivity and activate hippocampal neurons in control rats. Moreover, YTHDC1, the only m6A-associated protein predicted by bioinformatics to bind to circKcnk9, modulated visceral hypersensitivity through regulating the nuclear export of circKcnk9 in an m6A-dependent manner. Notably, FISH data suggested that the increased nuclear staining of circKcnk9 caused by siYTHDC1 could be recovered by overexpression of YTHDC1 wild type (WT) but not YTHDC1 negative control (NC) in PC12 cells. Conclusions: Our findings reveal a new regulatory mechanism in progress of IBS, that is, METTL3 modulates visceral hypersensitivity through regulating the nuclear export of circKcnk9 in YTHDC1-dependent manner.

Overexpressed DDX3x promotes abdominal aortic aneurysm formation and activates AKT in ApoE knockout mice.

In recent years, abdominal aortic aneurysm (AAA) lesions have become one of the important diseases that threaten public health. Related studies have confirmed that the occurrence of abdominal aortic aneurysms is related to inflammatory stress, cell apoptosis, and elastic fiber degradation. DDX3x is thought to interact with inflammasomes such as NLRP3 to aggravate the process of the inflammatory response, but its role in the occurrence of AAA remains unclear. Since DDX3x is indispensable in animal embryonic growth, we used an adeno-associated virus to construct gene-overexpressing mice to induce aneurysm development through AngII infusion. The results indicated that the incidence of aneurysms, inflammatory cell infiltration, vascular smooth muscle cell transformation, and oxidative stress levels were significantly increased under the condition of DDX3x overexpression. At the signaling level, activation of the AKT pathway exacerbates aneurysm formation. Taken together, we believe that DDX3x plays a key role in the development of aneurysms and may be a new target for the treatment of aneurysm progression.

Stomatin-like protein-2 attenuates macrophage pyroptosis and H9c2 cells apoptosis by protecting mitochondrial function.

Myocytes undergoing hypoxia condition can recruit macrophages and cause pro-inflammation initiation around the injury area. Mitochondrial dysfunction is related to macrophage pyroptosis. Stomatin-like protein-2 (SLP-2) can regulate mitochondrial biogenesis and function. Whether SLP-2 could affect macrophage pyroptosis remains unclear. In this study, bone marrow derived macrophages (BMDMs) were extracted from WT and SLP-2 knocked out mice, then stimulated by LPS/Nigericin. Western blot showed that SLP-2-/- promoted the expression of NLRP3, GSDMD-N, caspase-11 in macrophages, which means the deficiency of SLP-2 augments macrophage pyroptosis. Higher fluorescence intensity of dihydroethidium and TUNEL represented the increased ROS releasing and macrophage programmed death in SLP-2 deficiency groups. The immunofluorescence intensity of MtioTracker Red decreased and that of mitochondrial ROS (mtROS) increased in SLP-2 deletion groups with LPS/Nigericin stimulation, representing the increased mitochondrial damage. The expression level of HIF-1α increased in SLP-2 deletion macrophages with LPS and Nigericin stimulation. The level of Parkin and the ratio of LC3II/I decreased in SLP-2 deficiency macrophages after stimulated by LPS/Nigericin, compared with untreated macrophages. H9c2 cells were cultured in hypoxia condition before being cocultured with macrophage supernatant. The cocultured H9c2 cells were injured due to the serious pyroptosis of SLP-2 deficiency macrophages. According to these results, we suggest that SLP-2 can reduce macrophage pyroptosis and relieve hypoxia H9c2 cells injury through protecting mitochondrial function.

New Insights into the Role of Oral Microbiota Dysbiosis in the Pathogenesis of Inflammatory Bowel Disease.

Inflammatory bowel disease (IBD) is a group of chronic intestinal inflammatory disorders with a prolonged duration characterized by recurrent relapse and remission. The exact etiology of IBD remains poorly understood despite the identification of relevant risk factors, including individual genetic susceptibility, environmental triggers, and disruption of immune homeostasis. Dysbiosis of the gut microbiota is believed to exacerbate the progression of IBD. Recently, increasing evidence has also linked oral microbiota dysbiosis with the development of IBD. On the one hand, IBD patients show significantly unbalanced composition and function of the oral microbiota known as dysbiosis. On the other, overabundances of oral commensal bacteria with opportunistic pathogenicity have been found in the gut microbiota of IBD patients. Herein, we review the current information on the causative factors of IBD, especially recent evidence of IBD-associated oral microbiota dysbiosis, which has seldom been covered in the previous literature review, highlighting the pathogenic mechanisms of specific oral bacteria in the development of IBD. Ectopic colonization of several oral bacteria, including a subset of Porphyromonas gingivalis, Streptococcus mutans, Fusobacterium nucleatum, Campylobacter concisus, and Klebsiella pneumoniae, may lead to destruction of the intestinal epithelial barrier, excessive secretion of inflammatory cytokines, disruption of the host immune system, and dysbiosis of gut microbiota, consequently aggravating chronic intestinal inflammation. Studying oral microbiota dysbiosis may open future horizons for understanding IBD pathogenesis and provide novel biomarkers for IBD. This review also presents the current treatment and new perspectives for IBD treatment.

Structural and functional studies of TBC1D23 C-terminal domain provide a link between endosomal trafficking and PCH.

Pontocerebellar hypoplasia (PCH) is a group of neurological disorders that affect the development of the brain, in particular, the pons and cerebellum. Homozygous mutations of TBC1D23 have been found recently to lead to PCH; however, the underlying molecular mechanisms remain unclear. Here, we show that the crystal structure of the TBC1D23 C-terminal domain adopts a Pleckstrin homology domain fold and selectively binds to phosphoinositides, in particular, PtdIns(4)P, through one surface while binding FAM21 via the opposite surface. Mutation of key residues of TBC1D23 or FAM21 selectively disrupts the endosomal vesicular trafficking toward the Trans-Golgi Network. Finally, using the zebrafish model, we show that PCH patient-derived mutants, impacting either phosphoinositide binding or FAM21 binding, lead to abnormal neuronal growth and brain development. Taken together, our data provide a molecular basis for the interaction between TBC1D23 and FAM21, and suggest a plausible role for PtdIns(4)P in the TBC1D23-mediating endosome-to-TGN trafficking pathway. Defects in this trafficking pathway are, at least partially, responsible for the pathogenesis of certain types of PCH.

Nanosheets with High-Performance Electrochemical Oxygen Reduction Reaction Revived from Green Walnut Peel.

The synthesis of metal-free carbon-based electrocatalysts for oxygen reduction reactions (ORR) to replace conventional Pt-based catalysts has become a hot spot in current research. This work proposes an activation-assisted carbonization strategy, to manufacture N-doped ultra-thin carbon nanosheets (GWS180M800) with high catalytic activity, namely, melamine is used as an accelerator/nitrogen source, and walnut green peels biological waste as a carbon source. The melamine acts as a nitrogen donor in the hydrothermal process, effectively enhancing the nitrogen doping rate. The content of pyridine nitrogen groups accounts for up to 48.5% of the total nitrogen content. Electrochemical tests show that the GWS180M800 has excellent ORR electrocatalytic activity and stability, and makes a quasi-four-electron ORR pathway clear in the alkaline electrolyte. The initial potential and half slope potential are as high as 1.01 and 0.82 V vs. RHE, respectively. The GWS180M800 catalyst has a better ability to avoid methanol cross poisoning than Pt/C has. Compared with 20 wt% Pt/C, GWS180M800 has improved methanol tolerance and stability. It is a metal-free biochar ORR catalyst with great development potential and application prospects. This result provides a new space for the preparation of valuable porous nano-carbon materials based on carbonaceous solid waste and provides new ideas for catalyzing a wide range of electrochemical reactions in the future.

4'-SCF3 -Labeling Constitutes a Sensitive 19 F NMR Probe for Characterization of Interactions in the Minor Groove of DNA.

Fluorinated nucleotides are invaluable for 19 F NMR studies of nucleic acid structure and function. Here, we synthesized 4'-SCF3 -thymidine (T 4 ' - SCF 3 ${{^{4{^\prime}\hbox{-}{\rm SCF}{_{3}}}}}$ ) and incorporated it into DNA by means of solid-phase DNA synthesis. NMR studies showed that the 4'-SCF3 group exhibited a flexible orientation in the minor groove of DNA duplexes and was well accommodated by various higher order DNA structures. The three magnetically equivalent fluorine atoms in 4'-SCF3 -DNA constitute an isolated spin system, offering high 19 F NMR sensitivity and excellent resolution of the positioning of T 4 ' - SCF 3 ${{^{4{^\prime}\hbox{-}{\rm SCF}{_{3}}}}}$ within various secondary and tertiary DNA structures. The high structural adaptability and high sensitivity of T 4 ' - SCF 3 ${{^{4{^\prime}\hbox{-}{\rm SCF}{_{3}}}}}$ make it a valuable 19 F NMR probe for quantitatively distinguishing diverse DNA structures with single-nucleotide resolution and for monitoring the dynamics of interactions in the minor groove of double-stranded DNA.

Inhibition of LRRK2 restores parkin-mediated mitophagy and attenuates intervertebral disc degeneration.

OBJECTIVE: To elucidate the role of LRRK2 in intervertebral disc degeneration (IDD) as well as its mitophagy regulation mechanism. METHODS: The expression of LRRK2 in human degenerative nucleus pulposus tissues as well as in oxidative stress-induced rat nucleus pulposus cells (NPCs) was detected by western blot. LRRK2 was knocked down in NPCs by lentivirus (LV)-shLRRK2 transfection; apoptosis and mitophagy were assessed by western blot, TUNEL assay, immunofluorescence staining and mitophagy detection assay in LRRK2-deficient NPCs under oxidative stress. After knockdown of Parkin in NPCs with siRNA transfection, apoptosis and mitophagy were further assessed. In puncture-induced rat IDD model, X-ray, MRI, hematoxylin-eosin (HE) and Safranin O-Fast green (SO) staining were performed to evaluate the therapeutic effects of LV-shLRRK2 on IDD. RESULTS: We found that the expression of LRRK2 was increased in degenerative NPCs both in vivo and in vitro. LRRK2 deficiency significantly suppressed oxidative stress-induced mitochondria-dependent apoptosis in NPCs; meanwhile, mitophagy was promoted. However, these effects were abolished by the mitophagy inhibitor, suggesting the effect of LRRK2 on apoptosis in NPCs is mitophagy-dependent. Furthermore, Parkin knockdown study showed that LRRK2 deficiency activated mitophagy by recruiting Parkin. In vivo study demonstrated that LRRK2 inhibition ameliorated IDD in rats. CONCLUSIONS: The results revealed that LRRK2 is involved in the pathogenesis of IDD, while knockdown of LRRK2 inhibits oxidative stress-induced apoptosis through mitophagy. Thus, inhibition of LRRK2 may be a promising therapeutic strategy for IDD.

C4'-Fluorinated Oligodeoxynucleotides: Synthesis, Stability, Structural Studies.

Fluoro-substitution on the ribose moiety (e. g., 2'-F-deoxyribonucleotide) represents a popular way to modulate the ribose conformation and, hence, the structure and function of nucleic acids. In the present study, we synthesized 4'-F-deoxythymidine (4'-F T) and introduced it to oligodeoxyribonucleotides (ODNs). Though scission of the glycosylic bond of 4'-F T followed by strand cleavage occurred to some extent under alkaline conditions, the 4'-F T-modified ODNs were rather stable in neutral buffers. NMR studies showed that like 2'-F-deoxyribonucleoside, 4'-F T exists predominantly in the North conformation not only in the nucleoside form but also in the context of ODN strands. Circular dichroism spectroscopy, thermal denaturing and RNase H1 footprinting studies of 4'-F T-modified ODN/cDNA and ODN/cRNA duplexes indicated that the North conformation tendency of 4'-F T is maintained in the duplexes, leading to a local structural perturbation. Collectively, 4'-F-deoxyribonucleotide structurally resembles the 2'-F-deoxyribonucleotide but imparts less structural perturbation to the duplex than the latter.

Bioconversion of recombinantly produced precursor peptide pqqA into pyrroloquinoline quinone (PQQ) using a cell-free in vitro system.

Pyrroloquinoline quinone (PQQ) has been recognized as the third class of redox cofactors in addition to the well-known nicotinamides (NAD(P)+) and flavins (FAD, FMN). It plays important physiological roles in various organisms and has strong antioxidant properties. The biosynthetic pathway of PQQ involves a gene cluster composed of 4-7 genes, named pqqA-G, among which pqqA is a key gene for PQQ synthesis, encoding the precursor peptide PqqA. To produce recombinant PqqA in E. coli, fusion tags were used to increase the stability and solubility of the peptide, as well simplify the scale-up of the fermentation process. In this paper, pqqA from Gluconobacter oxydans 621H was expressed in E. coli BL21 (DE3) as a fusion protein with SUMO and purified using a hexahistidine (His6) tag. The SUMO fusion protein and His6 tag were specifically recognized and cleaved by the SUMO specific ULP protease, and immobilized-metal affinity chromatography was used to obtain high-purity precursor peptide PqqA. Expression and purification of target proteins was confirmed by Tricine-SDS-PAGE. Finally, the synthesis of PQQ in a cell-free enzymatic reaction in vitro was confirmed by LC-MS.

20-Deoxyingenol alleviates osteoarthritis by activating TFEB in chondrocytes.

Osteoarthritis (OA) is an age-related degenerative disease and currently cannot be cured. Transcription factor EB (TFEB) is one of the major transcriptional factors that regulates autophagy and lysosomal biogenesis. TFEB has been shown to be an effective therapeutic target for many diseases including OA. The current study explores the therapeutic effects of 20-Deoxyingenol (20-DOI) on OA as well as its working mechanism on TFEB regulation. The in vitro study showed that 20-DOI may suppress apoptosis and senescence induced by oxidative stress in chondrocytes; it may also promote the nuclear localization of TFEB in chondrocytes. Knock-down of TFEB compromised the effects of 20-DOI on apoptosis and senescence. The in vivo study demonstrated that 20-DOI may postpone the progression of OA in mouse destabilization of the medial meniscus (DMM) model; it may also suppress apoptosis and senescence and promote the nuclear localization of TFEB in chondrocytes in vivo. This work suggests that 20-Deoxyingenol may alleviate osteoarthritis by activating TFEB in chondrocytes, while 20-DOI may become a potential drug for OA therapy.