Satellite cell-derived TRIM28 is pivotal for mechanical load- and injury-induced myogenesis.

Satellite cells are skeletal muscle stem cells that contribute to postnatal muscle growth, and they endow skeletal muscle with the ability to regenerate after a severe injury. Here we discover that this myogenic potential of satellite cells requires a protein called tripartite motif-containing 28 (TRIM28). Interestingly, different from the role reported in a previous study based on C2C12 myoblasts, multiple lines of both in vitro and in vivo evidence reveal that the myogenic function of TRIM28 is not dependent on changes in the phosphorylation of its serine 473 residue. Moreover, the functions of TRIM28 are not mediated through the regulation of satellite cell proliferation or differentiation. Instead, our findings indicate that TRIM28 regulates the ability of satellite cells to progress through the process of fusion. Specifically, we discover that TRIM28 controls the expression of a fusogenic protein called myomixer and concomitant fusion pore formation. Collectively, the outcomes of this study expose the framework of a novel regulatory pathway that is essential for myogenesis.

The Transcription Factor Tbx5-Dependent Epigenetic Modification Contributes to Neuropathic Allodynia by Activating TRPV1 Expression in the Dorsal Horn.

Nerve injury can induce aberrant changes in the spine; these changes are due to, or at least partly governed by, transcription factors that contribute to the genesis of neuropathic allodynia. Here, we showed that spinal nerve ligation (SNL, a clinical neuropathic allodynia model) increased the expression of the transcription factor Tbx5 in the injured dorsal horn in male Sprague Dawley rats. In contrast, blocking this upregulation alleviated SNL-induced mechanical allodynia, and there was no apparent effect on locomotor function. Moreover, SNL-induced Tbx5 upregulation promoted the recruitment and interaction of GATA4 and Brd4 by enhancing its binding activity to H3K9Ac, which was enriched at the Trpv1 promotor, leading to an increase in TRPV1 transcription and the development of neuropathic allodynia. In addition, nerve injury-induced expression of Fbxo3, which abates Fbxl2-dependent Tbx5 ubiquitination, promoted the subsequent Tbx5-dependent epigenetic modification of TRPV1 expression during SNL-induced neuropathic allodynia. Collectively, our findings indicated that spinal Tbx5-dependent TRPV1 transcription signaling contributes to the development of neuropathic allodynia via Fbxo3-dependent Fbxl2 ubiquitination and degradation. Thus, we propose a potential medical treatment strategy for neuropathic allodynia by targeting Tbx5.

Comparing Low- or Standard-Dose Alteplase in Endovascular Thrombectomy: Insights From a Nationwide Registry.

BACKGROUND: Timely intravenous thrombolysis and endovascular thrombectomy are the standard reperfusion treatments for large vessel occlusion stroke. Currently, it is unknown whether a low-dose thrombolytic agent (0.6 mg/kg alteplase) can offer similar efficacy to the standard dose (0.9 mg/kg alteplase). METHODS: We enrolled consecutive patients in the multicenter Taiwan Registry of Endovascular Thrombectomy for Acute Ischemic Stroke who had received combined thrombolysis (within 4.5 hours of onset) and thrombectomy treatment from January 2019 to April 2023. The choice of low- or standard-dose alteplase was based on the physician's discretion. The outcomes included successful reperfusion (modified Thrombolysis in Cerebral Infarction score, 2b-3), symptomatic intracerebral hemorrhage, 90-day modified Rankin Scale score, and 90-day mortality. The outcomes between the 2 groups were compared using multivariable logistic regression and inverse probability of treatment weighting-adjusted analysis. RESULTS: Among the 2242 patients in the Taiwan Registry of Endovascular Thrombectomy for Acute Ischemic Stroke, 734 (33%) received intravenous alteplase. Patients in the low-dose group (n=360) were older, had more women, more atrial fibrillation, and longer onset-to-needle time compared with the standard-dose group (n=374). In comparison to low-dose alteplase, standard-dose alteplase was associated with a lower rate of successful reperfusion (81% versus 87%; adjusted odds ratio, 0.63 [95% CI, 0.40-0.98]), a numerically higher incidence of symptomatic intracerebral hemorrhage (6.7% versus 3.9%; adjusted odds ratio, 1.81 [95% CI, 0.88-3.69]), but better 90-day modified Rankin Scale score (functional independence [modified Rankin Scale score, 0-2], 47% versus 31%; adjusted odds ratio, 1.91 [95% CI, 1.28-2.86]), and a numerically lower mortality rate (9% versus 15%; adjusted odds ratio, 0.73 [95% CI, 0.43-1.25]) after adjusting for covariates. Similar results were observed in the inverse probability of treatment weighting-adjusted models. The results were consistent across predefined subgroups and age strata. CONCLUSIONS: Despite the lower rate of successful reperfusion and higher risk of symptomatic intracerebral hemorrhage with standard-dose alteplase, standard-dose alteplase was associated with a better functional outcome in patients receiving combined thrombolysis and thrombectomy.

Photo-protection and photo-inhibition during light induction in Barbula indica and Conocephalum conicum under different light gradients.

The objectives of this study were to measure the chlorophyll fluorescence (ChlF) parameters of Barbula indica (Hook.) Spreng and Conocephalum conicum (L.) Dumort subjected to various light intensities (LI) as a reflection of their adaptability to their habitats. The electron transport rate (ETR) of all plants under 500 µmol m-2 s-1 photosynthetic photon flux density (PPFD) was significantly higher than other LI treatments, implying that these plants could be grown under a specific and optimal light intensity adapted to 500 PPFD conditions. As LI increased from 50 to 2,000 PPFD, we observed in all plants increased non-photochemical quenching (NPQ) and photo-inhibitory quenching (qI) and decreased photosystem II efficiency (ΦPSII), potential quantum efficiency of PSII (Fv/Fm), actual PSII efficiency (ΔF/Fm'%), and Fv/Fm%. In addition, energy-dependent quenching (qE), the light protection system (qE + qZ + qT), and qI increased as ΦPSII decreased and photo-inhibition% increased under 1000, 1500, and 2000 PPFD conditions, suggesting that these plants had higher photo-protective ability under high LI treatments to maintain higher photosynthetic system performance. B. indica plants remained photochemically active and maintained higher qE under 300, 500, and 1000 PPFD, whereas C. conicum qZ + qT exhibited higher photo-protection under 500, 1000, and 1500 PPFD conditions. These ChlF indices can be used for predicting photosynthetic responses to light induction in different bryophytes and provide a theoretical basis for ecological monitoring.

E2F7 drives autotaxin/Enpp2 transcription via chromosome looping: Repression by p53 in murine but not in human carcinomas.

Dysregulation of the autotaxin (ATX, Enpp2)-lysophosphatidic acid (LPA) signaling in cancerous cells contributes to tumorigenesis and therapy resistance. We previously found that ATX activity was elevated in p53-KO mice compared to wild-type (WT) mice. Here, we report that ATX expression was upregulated in mouse embryonic fibroblasts from p53-KO and p53R172H mutant mice. ATX promoter analysis combined with yeast one-hybrid testing revealed that WT p53 directly inhibits ATX expression via E2F7. Knockdown of E2F7 reduced ATX expression and chromosome immunoprecipitation showed that E2F7 promotes Enpp2 transcription through cooperative binding to two E2F7 sites (promoter region -1393 bp and second intron 996 bp). Using chromosome conformation capture, we found that chromosome looping brings together the two E2F7 binding sites. We discovered a p53 binding site in the first intron of murine Enpp2, but not in human ENPP2. Binding of p53 disrupted the E2F7-mediated chromosomal looping and repressed Enpp2 transcription in murine cells. In contrast, we found no disruption of E2F7-mediated ENPP2 transcription via direct p53 binding in human carcinoma cells. In summary, E2F7 is a common transcription factor that upregulates ATX in human and mouse cells but is subject to steric interference by direct intronic p53 binding only in mice.

LPA suppresses HLA-DR expression in human melanoma cells: a potential immune escape mechanism involving LPAR1 and DR6-mediated release of IL-10.

While immune checkpoint inhibitors (ICIs) are promising in the treatment of metastatic melanoma, about half of patients do not respond well to them. Low levels of human leukocyte antigen-DR (HLA-DR) in tumors have been shown to negatively influence prognosis and response to ICIs. Lysophosphatidic acid (LPA) is produced in large amounts by melanoma and is abundantly present in the tumor microenvironment. LPA induces the release of various cytokines and chemokines from tumor cells, which affect cancer development, metastasis, and tumor immunity. In the present study, we investigated the role of LPA-induced IL-10 release in regulating HLA-DR expression and the underlying mechanisms in human melanoma cells. We showed that LPA (0.001-10 µM) dose-dependently increased DR6 transcript levels through activating LPAR1 in HEK293T cells. Knockdown of NF-κB1 abrogated the LPA-increased DR6 expression without affecting basal DR6 expression in both A2058 and A375 melanoma cell lines. LPA (10 µM) significantly increased IL-10 transcripts in A2058 and A375 melanoma cells, the effect was abolished by pharmacological inhibition of LPAR1 or knockdown of DR6. We found a statistically significant correlation between the expression of LPAR1, DR6 and IL-10 in human melanoma tissue and an association between increased expression of LPAR1 and reduced effectiveness of ICI therapy. We demonstrated that LPA (10 µM) markedly suppressed HLA-DR expression in both A375 and A2058 melanoma cells via activating the LPAR1-DR6-IL-10 pathway. These data suggest that the LPAR1-DR6-IL-10 autocrine loop could constitute a novel mechanism used by tumor cells to evade immunosurveillance by decreasing HLA-DR expression.

Determinants of early chronic kidney disease in patients with recently diagnosed type 2 diabetes mellitus: a retrospective study from the Taiwan Diabetes Registry.

BACKGROUND: We tried to identify the risk factor associate with early chronic kidney disease (CKD) in recently diagnosed type 2 diabetes mellitus patients by utilizing real-world data from Taiwan Diabetes Registry. MATERIALS AND METHODS: Patients with type 2 diabetes mellitus recently diagnosed within 1 year. We divided the study participants into control group and early CKD group. Early CKD was defined as either CKD stage G1 with albuminuria, CKD stage G2 with albuminuria, or CKD stage G3a regardless of albuminuria (Urine-albumin to creatinine ratio (UACR) ≥ 3 mg/mmol). Control group was defined as CKD G1 or CKD G2 without albuminuria. Logistic regression analyses were used to compare differences in clinical characteristics between the subgroups. Linear regression models were employed to examine the factors predicting estimated glomerular filtration rate (eGFR) and UACR. RESULTS: Total 2217 patients with recently diagnosed type 2 diabetes mellitus were included. 1545 patients were assigned to control group and 618 patients were assigned to the early CKD group. Age (odds ratio (OR) 1.215, 95% confidence interval [CI] 1.122-1.316), systolic blood pressure (OR 1.203, 95% CI 1.117-1.296), glycated hemoglobin (OR 1.074, 95% CI 1.023-1.129) and triglyceride (OR 2.18, 95% CI 1.485-3.199) were found to be significant risk factors. Further, presence of bidirectional association between UACR and eGFR was found. CONCLUSIONS: We reported factors associated with early CKD in recently diagnosed type 2 diabetes mellitus patients. Variables that associated with eGFR and UACR were identified respectively, included a mutual influence between UACR and eGFR.

A simple, organized web-based system improved the transfer efficiency and patient outcomes for endovascular thrombectomy in regional stroke network.

BACKGROUND: Endovascular thrombectomy (EVT) is a time-sensitive treatment for acute ischemic stroke with large vessel occlusion. To optimize transfer efficiency, a web-based platform was introduced in the Tainan Stroke Network (TSN). We assessed its application and effectiveness in regional stroke care. METHOD: This new web-based platform containing a questionnaire-style interface was introduced on October 1, 2021. To assess the transfer efficiency and patient outcomes, acute stroke patients transferred from PSCs to CSC for EVT from April 01, 2020, to December 30, 2022, were enrolled. The patients were classified into the traditional transferal pathway (TTP) group and the new transferal pathway (NTP) group depending on mode of transfer. Patient characteristics, time segments after stroke onset and outcome were compared between groups. RESULT: A total of 104 patients were enrolled, with 77 in the TTP group and 27 in the NTP group. Compared to the TTP group, the NTP group had a significantly shorter onset-to-CSC door time (TTP vs. NTP: 267 vs. 198 min; p = 0.041) and a higher EVT rate (TTP vs. NTP: 18.2% vs. 48.1%, p = 0.002). Among EVT patients, those in the NTP group had a significantly shorter CSC door-to-puncture time (TTP vs. NTP: 131.5 vs. 110 min; p = 0.029). The NTP group had a higher rate of good functional outcomes at 3 months (TTP vs. NTP: 21% vs. 61.5%; p = 0.034). CONCLUSION: This new web-based EVT transfer system provides notable improvements in clinical outcomes, transfer efficiency, and EVT execution for potential EVT candidates without markedly changing the regional stroke care paradigm.

Lysophosphatidic Acid Receptor 3 Activation Is Involved in the Regulation of Ferroptosis.

Ferroptosis, a unique form of programmed cell death trigged by lipid peroxidation and iron accumulation, has been implicated in embryonic erythropoiesis and aging. Our previous research demonstrated that lysophosphatidic acid receptor 3 (LPA3) activation mitigated oxidative stress in progeria cells and accelerated the recovery of acute anemia in mice. Given that both processes involve iron metabolism, we hypothesized that LPA3 activation might mediate cellular ferroptosis. In this study, we used an LPA3 agonist, 1-Oleoyl-2-O-methyl-rac-glycerophosphothionate (OMPT), to activate LPA3 and examine its effects on the ferroptosis process. OMPT treatment elevated anti-ferroptosis gene protein expression, including solute carrier family 7 member 11 (SLC7A11), glutathione peroxidase 4 (GPX4), heme oxygenase-1 (HO-1), and ferritin heavy chain (FTH1), in erastin-induced cells. Furthermore, OMPT reduced lipid peroxidation and intracellular ferrous iron accumulation, as evidenced by C11 BODIPY™ 581/591 Lipid Peroxidation Sensor and FerroOrange staining. These observations were validated by applying LPAR3 siRNA in the experiments mentioned above. In addition, the protein expression level of nuclear factor erythroid 2-related factor (NRF2), a key regulator of oxidative stress, was also enhanced in OMPT-treated cells. Lastly, we verified that LPA3 plays a critical role in erastin-induced ferroptotic human erythroleukemia K562 cells. OMPT rescued the erythropoiesis defect caused by erastin in K562 cells based on a Gly A promoter luciferase assay. Taken together, our findings suggest that LPA3 activation inhibits cell ferroptosis by suppressing lipid oxidation and iron accumulation, indicating that ferroptosis could potentially serve as a link among LPA3, erythropoiesis, and aging.

Optimization of aqueous extraction of antioxidants from Chrysanthemum (C. morifolium Ramat and C. indicum L.) flowers and evaluation of their protection from glycoxidation damage on human αA-crystallin.

Chrysanthemum tea is commonly consumed by Chinese consumers mainly due to the Chrysanthemum flower being a potential source of antioxidants. The current study investigates the effects of extraction time and temperature on Chrysanthemum flower aqueous extract (CFAE) antioxidant capacity, including Trolox equivalent antioxidant capacity (TEAC), ferrous iron-chelating activity, and superoxide radical scavenging capacity (SRSC) using a two-factor, three-level factorial design of the response surface method (RSM). The TEAC and SRSC of CFAE are higher at higher temperatures and longer times up to a certain point, and the highest TEAC and SRSC are achieved at a 100 °C extraction temperature for 45 min. The fructose induced-αA-crystallin (Cry) glycation model system was used to evaluate the effects of the CFAE on anti-glycoxidation activities. The antioxidant ingredients obtained from CFAE significantly impede the production of advanced glycation end products from protein glycoxidation products (dityrosine, kynurenine, and N'-methylkynurenine) in the glycation process of αA-Cry and exhibit strong anti-glycating activity. The glycation inhibitory effects of CFAE are concentration-dependent. C. indicum L. exhibits greater potential for preventing cataracts compared to C. morifolium Ramat CFAE's antioxidant and anti-glycation properties suggest its potential application as a natural ingredient in the development of agents to combat glycation.

Phosphorylated Upstream Frameshift 1-dependent Nonsense-mediated µ-Opioid Receptor mRNA Decay in the Spinal Cord Contributes to the Development of Neuropathic Allodynia-like Behavior in Rats.

BACKGROUND: Nonsense-mediated messenger RNA (mRNA) decay increases targeted mRNA degradation and has been implicated in the regulation of gene expression in neurons. The authors hypothesized that nonsense-mediated µ-opioid receptor mRNA decay in the spinal cord is involved in the development of neuropathic allodynia-like behavior in rats. METHODS: Adult Sprague-Dawley rats of both sexes received spinal nerve ligation to induce neuropathic allodynia-like behavior. The mRNA and protein expression contents in the dorsal horn of animals were measured by biochemical analyses. Nociceptive behaviors were evaluated by the von Frey test and the burrow test. RESULTS: On Day 7, spinal nerve ligation significantly increased phosphorylated upstream frameshift 1 (UPF1) expression in the dorsal horn (mean ± SD; 0.34 ± 0.19 in the sham ipsilateral group vs. 0.88 ± 0.15 in the nerve ligation ipsilateral group; P < 0.001; data in arbitrary units) and drove allodynia-like behaviors in rats (10.58 ± 1.72 g in the sham ipsilateral group vs. 1.19 ± 0.31 g in the nerve ligation ipsilateral group, P < 0.001). No sex-based differences were found in either Western blotting or behavior tests in rats. Eukaryotic translation initiation factor 4A3 (eIF4A3) triggered SMG1 kinase (0.06 ± 0.02 in the sham group vs. 0.20 ± 0.08 in the nerve ligation group, P = 0.005, data in arbitrary units)-mediated UPF1 phosphorylation, leading to increased nonsense-mediated mRNA decay factor SMG7 binding and µ-opioid receptor mRNA degradation (0.87 ± 0.11-fold in the sham group vs. 0.50 ± 0.11-fold in the nerve ligation group, P = 0.002) in the dorsal horn of the spinal cord after spinal nerve ligation. Pharmacologic or genetic inhibition of this signaling pathway in vivo ameliorated allodynia-like behaviors after spinal nerve ligation. CONCLUSIONS: This study suggests that phosphorylated UPF1-dependent nonsense-mediated µ-opioid receptor mRNA decay is involved in the pathogenesis of neuropathic pain.

Phosphate NIMA-Related Kinase 2-Dependent Epigenetic Pathways in Dorsal Root Ganglion Neurons Mediates Paclitaxel-Induced Neuropathic Pain.

BACKGROUND: The microtubule-stabilizing drug paclitaxel (PTX) is an important chemotherapeutic agent for cancer treatment and causes peripheral neuropathy as a common side effect that substantially impacts the functional status and quality of life of patients. The mechanistic role for NIMA-related kinase 2 (NEK2) in the progression of PTX-induced neuropathic pain has not been established. METHODS: Adult male Sprague-Dawley rats intraperitoneally received PTX to induce neuropathic pain. The protein expression levels in the dorsal root ganglion (DRG) of animals were measured by biochemical analyses. Nociceptive behaviors were evaluated by von Frey tests and hot plate tests. RESULTS: PTX increased phosphorylation of the important microtubule dynamics regulator NEK2 in DRG neurons and induced profound neuropathic allodynia. PTX-activated phosphorylated NEK2 (pNEK2) increased jumonji domain-containing 3 (JMJD3) protein, a histone demethylase protein, to specifically catalyze the demethylation of the repressive histone mark H3 lysine 27 trimethylation (H3K27me3) at the Trpv1 gene, thereby enhancing transient receptor potential vanilloid subtype-1 (TRPV1) expression in DRG neurons. Moreover, the pNEK2-dependent PTX response program is regulated by enhancing p90 ribosomal S6 kinase 2 (RSK2) phosphorylation. Conversely, intrathecal injections of kaempferol (a selective RSK2 activation antagonist), NCL 00017509 (a selective NEK2 inhibitor), NEK2-targeted siRNA, GSK-J4 (a selective JMJD3 inhibitor), or capsazepine (an antagonist of TRPV1 receptor) into PTX-treated rats reversed neuropathic allodynia and restored silencing of the Trpv1 gene, suggesting the hierarchy and interaction among phosphorylated RSK2 (pRSK2), pNEK2, JMJD3, H3K27me3, and TRPV1 in the DRG neurons in PTX-induced neuropathic pain. CONCLUSIONS: pRSK2/JMJD3/H3K27me3/TRPV1 signaling in the DRG neurons plays as a key regulator for PTX therapeutic approaches.

Genetic and Biochemical Characterization of Halogenation and Drug Transportation Genes Encoded in the Albofungin Biosynthetic Gene Cluster.

Albofungin, a hexacyclic aromatic natural product, exhibits broad-spectrum antimicrobial activity. Its biosynthesis, regulation, and resistance remain elusive. Here, we report the albofungin (abf) biosynthetic gene cluster (BGC) from its producing strain Streptomyces tumemacerans JCM5050. The nascent abf BGC encodes 70 putative genes, including regulators, transporters, type II polyketide synthases (PKSs), oxidoreductase, and tailoring enzymes. To validate the intactness and functionality of the BGC, we developed an Escherichia coli-Streptomyces shuttle bacterial artificial chromosome system, whereby the abf BGC was integrated into the genome of a nonproducing host via heterologous conjugation, wherefrom albofungin can be produced, confirming that the BGC is in effect. We then delimited the boundaries of the BGC by means of in vitro CRISPR-Cas9 DNA editing, concluding a minimal but essential 60-kb abf BGC ranging from orfL to abf58. The orfA gene encoding a reduced flavin adenine dinucleotide (FADH2)-dependent halogenase was examined and is capable of transforming albofungin to halogen-substituted congeners in vivo and in vitro. The orfL gene encoding a transporter was examined in vivo. The presence/absence of orfA or orfL demonstrated that the MIC of albofungin is subject to alteration when an extracellular polysaccharide intercellular adhesin was formed. Despite that halogenation of albofungin somewhat increases binding affinity to transglycosylase (TGase), albofungin with/without a halogen substituent manifests similar in vitro antimicrobial activity. Halogenation, however, limits overall dissemination and effectiveness given a high secretion rate, weak membrane permeability, and high hydrophobicity of the resulting products, whereby the functions of orfA and orfL are correlated with drug detoxification/resistance for the first time. IMPORTANCE Albofungin, a natural product produced from Streptomycetes, exhibits bioactivities against bacteria, fungi, and tumor cells. The biosynthetic logic, regulations, and resistance of albofungin remain yet to be addressed. Herein, the minimal albofungin (abf) biosynthetic gene cluster (BGC) from the producing strain Streptomyces tumemacerans JCM5050 was precisely delimited using the Escherichia coli-Streptomyces shuttle bacterial artificial chromosome system, of which the gene essentiality was established in vivo and in vitro. Next, we characterized two genes orfA and orfL encoded in the abf BGC, which act as a reduced flavin adenine dinucleotide (FADH2)-dependent halogenase and an albofungin-congeners transporter, respectively. While each testing microorganism exhibited different sensitivities to albofungins, the MIC values of albofungins against testing strains with/without orfA and/or orfL were subject to considerable changes. Halogen-substituted albofungins mediated by OrfA manifested overall compromised dissemination and effectiveness, revealing for the first time that two functionally distinct proteins OrfA and OrfL are associated together, exerting a novel "belt and braces" mechanism in antimicrobial detoxification/resistance.

Integrated small RNA profiling and degradome analysis of Anthurium andraeanum cultivars with different-colored spathes.

MicroRNAs (miRNAs) are known to play vital roles in coloration of leaves, flowers, and fruits in plants. However, their functions in spathe coloration are poorly known. Anthurium andraeanum is a popular ornamental plant with various spathe colors. In this study, small RNA and degradome libraries from three A. andraeanum cultivars with different-colored spathes were constructed and sequenced. Illumina sequencing resulted in 94 conserved miRNAs, and 34 novel miRNAs in total were then identified based on precursor sequences and hairpin structures. Differential expression analysis showed that 52, 51, and 49 miRNAs were differentially expressed in comparisons of orange- versus white-colored spathe, purple- versus white-colored spathe, and purple- versus orange-colored spathe, respectively. The expression patterns of miRNAs and their corresponding targets involved in spathe coloration were further analyzed, and displayed that miR156b and miR529 were highly abundant in the spathes with higher anthocyanin content. These two miRNAs co-targeted a gene encoding SPL17, which may function as a negative regulator in anthocyanin accumulation. In addition, miR408 was also abundantly expressed in purple- and orange-colored spathes, and its typical targets were also identified. This comprehensive integrated analysis provides insight into the miRNA-mediated genetic regulation in spathe coloration of A. andraeanum.

Transcriptional regulation of lysophosphatidic acid receptors 2 and 3 regulates myeloid commitment of hematopoietic stem cells.

Lysophosphatidic acid (LPA) is one of the lipids identified to be involved in stem cell differentiation. It exerts various functions through activation of G protein-coupled lysophosphatidic acid receptors (LPARs). In previous studies, we have demonstrated that activation of LPA receptor 3 (LPA3) promotes erythropoiesis of human hematopoietic stem cells (HSCs) and zebrafish using molecular and pharmacological approaches. Our results show that treatment with lysophosphatidic acid receptor 2 (LPA2) agonist suppressed erythropoiesis, whereas activation of LPA3 by 1-oleoyl-2-methyl-sn-glycero-3-phosphothionate (2S-OMPT) promoted it, both in vitro and in vivo. Furthermore, we have demonstrated the inhibitory role of LPA3 during megakaryopoiesis. However, the mechanism underlying these observations remains elusive. In the present study, we suggest that the expression pattern of LPARs may be correlated with the transcriptional factors GATA-1 and GATA-2 at different stages of myeloid progenitors. We determined that manipulation of GATA factors affected the expression levels of LPA2 and LPA3 in K562 leukemia cells. Using luciferase assays, we demonstrate that the promoter regions of LPAR2 and LPAR3 genes were regulated by these GATA factors in HEK293T cells. Mutation of GATA-binding sites in these regions abrogated luciferase activity, suggesting that LPA2 and LPA3 are regulated by GATA factors. Moreover, physical interaction between GATA factors and the promoter region of LPAR genes was verified in K562 cells using chromatin immunoprecipitation (ChIP) studies. Taken together, our results suggest that balance between LPA2 and LPA3 expression, which may be determined by GATA factors, is a regulatory switch for lineage commitment in myeloid progenitors. The expression-level balance of LPA receptor subtypes represents a novel mechanism regulating erythropoiesis and megakaryopoiesis.

A novel naphthalimide derivative reduces platelet activation and thrombus formation via suppressing GPVI.

Naphthalimide derivatives have multiple biological activities, including antitumour and anti-inflammatory activities. We previously synthesized several naphthalimide derivatives; of them, compound 5 was found to exert the strongest inhibitory effect on human DNA topoisomerase II activity. However, the effects of naphthalimide derivatives on platelet activation have not yet been investigated. Therefore, the mechanism underlying the antiplatelet activity of compound 5 was determined in this study. The data revealed that compound 5 (5-10 µM) inhibited collagen- and convulxin- but not thrombin- or U46619-mediated platelet aggregation, suggesting that compound 5 is more sensitive to the inhibition of glycoprotein VI (GPVI) signalling. Indeed, compound 5 could inhibit the phosphorylation of signalling molecules downstream of GPVI, followed by the inhibition of calcium mobilization, granule release and GPIIb/IIIa activation. Moreover, compound 5 prevented pulmonary embolism and prolonged the occlusion time, but tended to prolong the bleeding time, indicating that it can prevent thrombus formation but may increase bleeding risk. This study is the first to demonstrate that the naphthalimide derivative compound 5 exerts antiplatelet and antithrombotic effects. Future studies should modify compound 5 to synthesize more potent and efficient antiplatelet agents while minimizing bleeding risk, which may offer a therapeutic potential for cardiovascular diseases.

A deep analysis of the proteomic and phosphoproteomic alterations that occur in skeletal muscle after the onset of immobilization.

KEY POINTS: A decrease in protein synthesis plays a major role in the loss of muscle mass that occurs in response to immobilization. In mice, immobilization leads to a rapid (within 6 h) and progressive decrease in the rate of protein synthesis and this effect is mediated by a decrease in translational efficiency. Deep proteomic and phosphoproteomic analyses of mouse skeletal muscles revealed that the rapid immobilization-induced decrease in protein synthesis cannot be explained by changes in the abundance or phosphorylation state of proteins that have been implicated in the regulation of translation. ABSTRACT: The disuse of skeletal muscle, such as that which occurs during immobilization, can lead to the rapid loss of muscle mass, and a decrease in the rate of protein synthesis plays a major role in this process. Indeed, current dogma contends that the decrease in protein synthesis is mediated by changes in the activity of protein kinases (e.g. mTOR); however, the validity of this model has not been established. Therefore, to address this, we first subjected mice to 6, 24 or 72 h of unilateral immobilization and then used the SUnSET technique to measure changes in the relative rate of protein synthesis. The result of our initial experiments revealed that immobilization leads to a rapid (within 6 h) and progressive decrease in the rate of protein synthesis and that this effect is mediated by a decrease in translational efficiency. We then performed a deep mass spectrometry-based analysis to determine whether this effect could be explained by changes in the expression and/or phosphorylation state of proteins that regulate translation. From this analysis, we were able to quantify 4320 proteins and 15,020 unique phosphorylation sites, and surprisingly, the outcomes revealed that the rapid immobilization-induced decrease in protein synthesis could not be explained by changes in either the abundance, or phosphorylation state, of proteins. The results of our work not only challenge the current dogma in the field, but also provide an expansive resource of information for future studies that are aimed at defining how disuse leads to loss of muscle mass.

Piriformospora indica colonization increases the growth, development, and herbivory resistance of sweet potato (Ipomoea batatas L.).

KEY MESSAGE: Piriformospora indica symbiosis promoted the growth and photosynthesis, and simultaneously enhanced the resistance against insect herbivory by regulating sporamin-dependent defense in sweet potato. Piriformospora indica (P. indica), a versatile endophytic fungus, promotes the growth and confers resistance against multiple stresses by root colonization in plant hosts. In this study, the effects of P. indica colonization on the growth, physiological change, and herbivore resistance of leaf-vegetable sweet potato cultivar were investigated. P. indica symbiosis significantly improved the biomass in both above- and under-ground parts of sweet potato plants. In comparison with the non-colonized plants, the content of photosynthetic pigments and the efficiency of photosynthesis were increased in P. indica-colonized sweet potato plants. Further investigation showed that the activity of catalase was enhanced in both leaves and roots of sweet potato plants after colonization, but ascorbate peroxidase, peroxidase, and superoxide dismutase were not enhanced. Furthermore, the interaction between P. indica and sweet potato plants also showed the biological function in jasmonic acid (JA)-mediated defense. The plants colonized by P. indica had greatly increased JA accumulation and defense gene expressions, including IbNAC1, IbbHLH3, IbpreproHypSys, and sporamin, leading to elevated trypsin inhibitory activity, which was consistent with a reduced Spodoptera litura performance when larvae fed on the leaves of P. indica-colonized sweet potato plants. The root symbiosis of P. indica is helpful for the plant promoting growth and development and has a strong function as resistance inducers against herbivore attack in sweet potato cultivation by regulating sporamin-dependent defense.

Serum uric acid and blood pressure among adolescents: data from the Nutrition and Health Survey in Taiwan (NAHSIT) 2010-2011.

PURPOSE: Elevated serum uric acid (UA) is frequently observed in adults with high blood pressure (BP); however, data from adolescents are limited. We examined the association between serum UA and BP in a nationally representative sample of Taiwan adolescents. MATERIAL AND METHODS: Some 1384 participants, aged 14-19 years, from the Nutrition and Health Survey in Taiwan 2010-2011 were included for the study. Elevated BP was defined as systolic or diastolic BP ≥120/80 mmHg. The analyses examined the relationship between serum UA and BP using linear regression and odds ratios of having an elevated BP using logistic regression. RESULTS: In this study population, the mean age was 16.0 years, mean serum UA was 5.8 mg/dL, 22.5% were obese (body mass index ≥24 kg/m2) and 9.8% had an elevated BP. Compared to girls, boys are more likely to be obese and to have higher serum UA and BP. After full adjustments, systolic BP, diastolic BP and mean arterial pressure increased 0.45, 0.48 and 0.47 mmHg, respectively, for each 1-mg/dL increase in UA (p = 0.07, 0.03 and 0.02, respectively). The odds of having an elevated BP were 3.4 times higher in subjects of the upper tertile of serum UA than those of the lower tertile (p = 0.02). CONCLUSION: Adolescents with factors as male, obesity, and UA ≥5.5 mg/dL were prone to have an elevated BP, regardless of age and family history of hypertension. The present study found that serum UA levels are significantly correlated to BP in Taiwanese adolescents.

Bioactive Compounds, Antioxidants, and Health Benefits of Sweet Potato Leaves.

Sweet potato (Ipomoea batatas) is one of the most important food crops worldwide and its leaves provide a dietary source of nutrients and various bioactive compounds. These constituents of sweet potato leaves (SPL) vary among varieties and play important roles in treating and preventing various diseases. Recently, more attentions in health-promoting benefits have led to several in vitro and in vivo investigations, as well as the identification and quantification of bioactive compounds in SPL. Among them, many new compounds have been reported as the first identified compounds from SPL with their dominant bioactivities. This review summarizes the current knowledge of the bioactive compositions of SPL and their health benefits. Since SPL serve as a potential source of micronutrients and functional compounds, they can be further developed as a sustainable crop for food and medicinal industries.