Cartilage stem/progenitor cells-derived exosomes facilitate knee cartilage repair in a subacute osteoarthritis rat model.

Cartilage defects in the knee are often associated with the progression of degenerative osteoarthritis (OA), and cartilage repair is a useful strategy for managing this disease. However, cartilage repair is challenging because of the unique environment within the tissue. Recently, stem cell-based therapies have shed new light on this issue. In this study, we prepared exosomes (EXOs) from cartilage stem/progenitor cells (CSPCs) and found that treatment with EXOs increased the viability, migration, and proliferation of cultured primary chondrocytes. In a subacute OA rat model, the application of EXOs facilitated cartilage regeneration as evidenced by histological staining. Exosomal protein analysis together with bioinformatics suggested that cyclin-dependent kinase 9 (CDK9) is a key factor for chondrocyte growth and migration. Functional studies confirmed this prediction, that is, inhibiting CDK9 reduced the beneficial effects induced by EXOs in primary chondrocytes; while overexpression of CDK9 recapitulated the EXOs-induced phenotypes. RNA-Seq data showed that a set of genes involved in cell growth and migration were up-regulated by EXOs in chondrocytes. These changes could be partially reproduced by CDK9 overexpression. Overall, our data suggest that EXOs derived from primary CSPCs hold great therapeutic potential for treating cartilage defect-associated disorders such as degenerative OA, and that CDK9 is a key factor in this process.

Changes in carbohydrate distribution in cotton photosynthetic organs and increase in boll weight reduce yield loss under high temperature.

Yield of cotton (Gossypium hirsutum) does not always fall with high temperature (HT) even though this induces significant reductions in fruit retention. To investigate the underlying mechanisms, a greenhouse experiment was conducted with two temperature regimes [control treatment, 28 °C; high temperature (HT), 34 °C] for 7 d. Results showed HT did not significantly influence cotton yield, but reduced boll number and increased boll weight. The 13C distribution ratio of the leaf subtending the cotton boll (LSCB) decreased while that of the cotton boll increased under HT. Transcriptomic and proteomic analyses of the LSCB revealed up-regulated genes involved in cytokinin and jasmonic acid synthesis, as well as SWEET15 (GH_D01G0218), which positively regulated photosynthesis and transport photosynthate, ultimately leading to increased boll weight. After 7 d recovery from HT, the 13C distribution ratio of the LSCB increased while that of the cotton boll decreased. However, boll weight still increased, which was related to increased amylase and sucrose phosphate synthase activities and up-regulated sucrose transport genes in the main-stem leaf and capsule wall. Thus, both accelerated sucrose synthesis and transport in the LSCB under HT and increased sucrose supply ability of the main-stem leaf and capsule wall after recovery from HT contributed to an increased boll weight, which finally maintained cotton yield.

Drought decreases cotton fiber strength by altering sucrose flow route.

The potential mechanisms by which drought restricts cotton fiber cell wall synthesis and fiber strength are still not fully understood. Herein, drought experiments were conducted using two cultivars of upland cotton (Gossypium hirsutum), Dexiamian 1 (drought-tolerant) and Yuzaomian 9110 (drought-sensitive). Results showed that drought notably reduced sucrose efflux from cottonseed coats to fibers by down-regulating the expression of GhSWEET10 and GhSWEET15 in outer cottonseed coats, leading to enhanced sucrose accumulation in cottonseed coats but decreased sucrose accumulation in fibers. Within cotton fibers, drought restricted the hydrolysis of sucrose to uridine-5'-diphosphoglucose by suppressing sucrose synthase activity, and drought favored the conversion of uridine-5'-diphosphoglucose to ß-1,3-glucan rather than cellulose by up-regulating GhCALS5. Hence, cellulose content was reduced, which was the main reason for the decreased fiber strength under drought. Moreover, drought promoted lignin synthesis by up-regulating the expression of Gh4CL4, GhPAL9, GhCCR5, GhCAD11, and GhCOMT6, which partly offset the negative influence of reduced cellulose content on fiber strength. Compared with Yuzaomian 9110, the drought-tolerance of Dexiamian 1 was evidenced by the following under drought conditions: (i) greater sucrose flow from seedcoat to fiber, (ii) less ß-1,3-glucan accumulation, and (iii) more lignin biosynthesis. Overall, this study provides new insights into the mechanism of reduced cotton fiber strength induced by drought.

MED1 Regulates BMP/TGF-ß in Endothelium: Implication for Pulmonary Hypertension.

BACKGROUND: Dysregulated BMP (bone morphogenetic protein) or TGF-ß (transforming growth factor beta) signaling pathways are imperative in idiopathic and familial pulmonary arterial hypertension (PAH) as well as experimental pulmonary hypertension (PH) in rodent models. MED1 (mediator complex subunit 1) is a key transcriptional co-activator and KLF4 (Krüppel-like factor 4) is a master transcription factor in endothelium. However, MED1 and KLF4 epigenetic and transcriptional regulations of the BMP/TGF-ß axes in pulmonary endothelium and their dysregulations leading to PAH remain elusive. We investigate the MED1/KLF4 co-regulation of the BMP/TGF-ß axes in endothelium by studying the epigenetic regulation of BMPR2 (BMP receptor type II), ETS-related gene (ERG), and TGFBR2 (TGF-ß receptor 2) and their involvement in the PH. METHODS: High-throughput screening involving data from RNA-seq, MED1 ChIP-seq, H3K27ac ChIP-seq, ATAC-seq, and high-throughput chromosome conformation capture together with in silico computations were used to explore the epigenetic and transcriptional regulation of BMPR2, ERG, and TGFBR2 by MED1 and KLF4. In vitro experiments with cultured pulmonary arterial endothelial cells (ECs) and bulk assays were used to validate results from these in silico analyses. Lung tissue from patients with idiopathic PAH, animals with experimental PH, and mice with endothelial ablation of MED1 (EC-MED1-/-) were used to study the PH-protective effect of MED1. RESULTS: Levels of MED1 were decreased in lung tissue or pulmonary arterial endothelial cells from idiopathic PAH patients and rodent PH models. Mechanistically, MED1 acted synergistically with KLF4 to transactivate BMPR2, ERG, and TGFBR2 via chromatin remodeling and enhancer-promoter interactions. EC-MED1-/- mice showed PH susceptibility. In contrast, MED1 overexpression mitigated the PH phenotype in rodents. CONCLUSIONS: A homeostatic regulation of BMPR2, ERG, and TGFBR2 in ECs by MED1 synergistic with KLF4 is essential for the normal function of the pulmonary endothelium. Dysregulation of MED1 and the resulting impairment of the BMP/TGF-ß signaling is implicated in the disease progression of PAH in humans and PH in rodent models.

Revisiting the association between grandparenting and mental health in China: New evidence from the harmonized CHARLS.

BACKGROUND: In the context of the global aging challenge, an increasing number of middle-aged and older adults (MAOAs) are engaging in grandparenting. However, the effect of grandparenting on the mental health of caregivers has shown inconsistent findings. To effectively promote healthy aging, it is imperative to adopt a comprehensive perspective and employ a rigorous approach to further investigate the relationship between these two social phenomena. METHODS: The data from the Harmonized China Health and Retirement Longitudinal Study were analyzed, focusing on MAOAs with at least one grandchild. Mental health assessments used the center for epidemiologic studies depression scale scale. The study employed a series of difference-in-differences (DID) models, especially complemented by propensity score matching, to evaluate the average treatment effect for the treated (ATT) on mental health of caregivers, considering covariates like personal and family characteristics. The intervention perspective includes both the provision and cessation of grandparenting. RESULTS: The study found that providing grandchildren care does not have a significant effect on the mental health of grandparents, in comparison to those who have never engaged in such care (ATT = -0.172, T = 0.65, p = 0.517 in the PSM-DID model). Furthermore, ceasing this care also appears to have no substantial effect on the mental health of the caregivers, relative to individuals who have consistently offered grandchildren care (ATT = 0.060, T = 0.26, p = 0.795 in the PSM-DID model). Furthermore, subsequent robustness analyses consistently supported these findings, even when considering data from different survey waves. CONCLUSIONS: In contrast to many prior studies that have reported either positive or negative effects, our research reveals that grandparenting exerts no significant effect on the mental health of MAOAs. Consequently, health practitioners and policymakers should carefully consider the diverse cultural context when tailoring interventions and support strategies.

Filial piety and older adult caregiving among Chinese and Chinese-American families in the United States: a concept analysis.

BACKGROUND: The culturally sensitive nursing practice has not embedded filial piety as a cultural value and stance pertaining to caregiving among aging Chinese and Chinese-American (CCA) families in the United States, yet it is critical for healthy aging among CCAs. PURPOSE: To understand filial piety when caring for aging CCAs and conceptualize an operational definition and framework. METHODS: A systematic search was conducted in CINAHL, PubMed, Scopus, and PsycINFO databases. Analysis of the concept of filial piety among CCAs used Walker and Avant's methods. Twenty-six studies were selected in the final full-text analysis. FINDINGS: Synthesis of evidence identified four antecedents: (a) filial obligation as a 'cultural gene', (b) sense of altruism, (c) familial solidarity, and (d) societal expectation of 'birth right'. Attributes included familial material and emotional support, obedience, pious reverence, and societal norms. Consequences were related to caregiver burden, psychological and physical well-being, quality of life, and health equity. CONCLUSION: Filial piety is an intrinsic desire to support aging parents and an extrinsic desire to adhere to Chinese societal moral tenets. The proposed operational framework "Caregiving for aging CCAs in the United States" merits further study.

Leaf anatomical alterations reduce cotton's mesophyll conductance under dynamic drought stress conditions.

Drought stress significantly affects cotton's net photosynthetic rate (A) by restraining stomatal (gs ) and mesophyll conductance (gm ) as well as perturbing its biochemical process, resulting in yield reductions. Despite the significant progress in dissecting effects of drought on photosynthesis, the variability observed in cotton's gm , and the mechanisms contributing to that variability under dynamic drought stress conditions are poorly understood. For that reason, a controlled-environment experiment with two cotton genotypes (Dexiamian 1, Yuzaomian 9110), three water levels (soil relative water content: control [75 ± 5]%, moderate drought [60 ± 5]%, severe drought [45 ± 5]%), and two drought durations (10 and 31 days) were conducted. The results indicated that the cotton boll biomass was significantly decreased under 10-day severe drought and 31-day moderate and severe drought. Decreases in gs were later accompanied by decreases in gm and further combined with reductions in electron transport rate, as drought stress progressed in duration and severity, ultimately resulting in significant reductions in A of subtending leaf. Stomatal and mesophyll conductance constraints were the primary factors limiting photosynthesis, while biochemical constraints decreased, as drought stress progressed. Considering gm , its decline was ascribed to increases in the diffusion resistance of CO2 through cytoplasm (rcyt ), under short- or long-term drought, as well as to increases in leaf dry mass (LMA), and decreases in the chloroplast surface area exposed to intercellular air space (Sc /S), under long-term drought. It was concluded that A could be enhanced, under dynamic drought stress conditions, by increasing gm through increasing Sc /S and reducing LMA and rcyt .

Combined effect of elevated temperature and drought stress on carbohydrate metabolism of cotton (Gossypium hirsutum L.) subtending leaves.

High temperatures and drought are expected to become more frequent in the future and last longer than ever before. To investigate their combined effect on leaves subtending cotton boll (LSCB), an experiment was conducted from 2016 to 2018 using a nonheat-tolerant cotton cultivar and a heat-tolerant cultivar. Two temperature regimes with ambient temperature (AT, 31.0/26.4°C) and elevated temperature (ET, 33.4/28.9°C, 2.5°C higher than AT) and three drought treatments with a soil relative water content (SRWC) of 75 ± 5%, 60 ± 5%, and 45 ± 5% were established repeatedly. ET decreased net photosynthetic rate (Pn), initial rubisco activity (4.1.1.39, RuBP) and cytosolicfructose-1,6-bisphosphatase (cy-FBPase; 3.1.3.11) activity, upregulated GhSuSyA, and GhSuSyD expressions, and increased SuSy (2.4.1.13) activity, which led to the decline of the final starch and sucrose contents. Moreover, RuBP, Pn, and starch content all decreased with drop in SRWC levels, but the cy-FBPase and SPS (2.4.1.14) activity increased, which in turn increased sucrose content. Under combined stresses, when the changing trends of ET and drought effects were the same, the decrease of Pn, RuBP, and starch content was greater than under single stress exposure. However, when the changing trends of ET and drought effects were adverse, the combined effects on indicators such as cy-FBPase, SuSy, sucrose content were mostly similar to drought stress. These results indicate that the effect of drought on carbohydrate metabolism in LSCB is more prominent than ET. Thus, the drought effect for carbohydrate metabolism in LSCB may need more attention than ET under combined heat and drought stress.

Auxin and abscisic acid play important roles in promoting glucose metabolism of reactivated young kernels of maize (Zea mays L.).

In maize, young kernels that are less competitive and have poor sink activity often abort. Studies have indicated that such poor competitiveness depends, in part, on the regulation by auxin (IAA) and abscisic acid (ABA). However, the mechanisms for such effects remain unclear. We used pollination-blocking and hand-pollination treatments accompanied by multi-omics and physiological tests, to identify underlying mechanism by which IAA and ABA, along with sugar signaling affect kernel development. Results showed that preventing pollination of the primary ears reactivated kernels in the secondary ears and altered both sugar metabolism and hormone signaling pathways. This was accompanied by increased enzyme activities in carbon metabolism and concentrations of glucose and starch, as well as increased levels of IAA and decreased levels of ABA in the reactivated kernels. Positive and negative correlations were observed between IAA, ABA contents and cell wall invertase (CWIN) activity, and glucose contents, respectively. In vitro culture revealed that the expression of genes involved in glucose utilization was upregulated by IAA, but downregulated by ABA. IAA could promote the expression of ABA signaling genes ZmPP2C9 and ZmPP2C13 but downregulated the expression of Zmnced5, an ABA biosynthesis gene, and ZmSnRK2.10, which is involved in ABA signal transduction. However, these genes showed opposite trends when IAA transport was inhibited. To summarize, we suggest a regulatory model for how IAA inhibits ABA metabolism by promoting the smooth utilization of glucose in reactivated young kernels. Our findings highlight the importance of IAA in ABA signaling by regulating glucose production and transport in maize.

Foliar melatonin ameliorates drought-induced alterations in enzyme activities of sugar and nitrogen metabolisms in cotton leaves.

Sugar and nitrogen metabolisms help plants maintain cellular homeostasis, stress tolerance, and sustainable growth in drought conditions. Melatonin, a potent antioxidant and signaling molecule, appears to mitigate the negative impacts of drought on plants. This study aimed to investigate the potential role of foliar-applied melatonin in ameliorating drought-induced alterations in leaf sugar and nitrogen metabolisms' enzyme activities during cotton flowering and boll formation. To date, no study has examined drought-induced sugar and nitrogen metabolisms' enzyme activity changes in cotton treated with foliar melatonin. Drought levels (FC1 = 75 ± 5%, FC2 = 60 ± 5%, and FC3 = 45 ± 5%) were maintained between 3 and 35 days after flowering (DAF), and melatonin (M) concentrations (0, 25, 50, and 100 µmol L-1 ) were applied at 3 and 21 DAF in a completely randomized design. M100 concentrations at low FC levels significantly enhanced leaf sugar and N-metabolic enzyme activities, such as sucrose synthase (65.56%) and glutamine synthetase (55.24%), compared to plants not treated with melatonin; peaking between 7 and 21 DAF and declining gradually with crop growth. Moreover, the M100 concentrations at all FC levels, particularly FC3, significantly increased the relative expression of GhSusB, GhSusC, SPS1, and SPS3 genes, indicating that melatonin improves leaf sugar and N-metabolism enzymatic activities under drought stress. Therefore, applying M100 concentrations to cotton foliage under FC3 conditions during reproductive stages improves leaf water status, sugar, and N-metabolism enzyme activities, demonstrating melatonin's potent anti-stress, osmoregulatory, and growth-promoting properties in overcoming drought stress in cotton crops. Future research into the molecular mechanisms of melatonin-mediated sugar and nitrogen metabolism enzyme activities in cotton leaves may lead to biotechnological methods to improve drought resilience in cotton and other crops.

Functional assessment of heart-specific enhancers by integrating ChIP-seq data.

BACKGROUND: Identification and functional annotations of regulatory sequences play a pivotal role in heart development and function. METHODS: To generate a map of human heart-specific enhancers, we performed an integrative analysis of 148 chromatin immunoprecipitation coupled to massively parallel sequencing (ChIP-seq) samples with enhancer-associated epigenetic marks from the heart, liver, brain, and kidney. Functional validation of heart-specific enhancer activity was then performed using cultured cells. RESULTS: A 144.6-Mb candidate heart-specific enhancer compendium was generated by integrating the analysis of 148 epigenomic data sets from human and mouse hearts and control tissues. To validate in vivo enhancer activity, we tested 12 of these sequences around 45 CHD-related genes in cultured cells and found that 8 (67%) have reproducible heart-specific enhancer activity. A functional analysis demonstrated that the identified human heart-specific enhancer wf1 regulates the FBN1 gene which is involved in heart disease. CONCLUSIONS: Our study provides an integrative analysis pipeline for ChIP-seq data and identified a comprehensive catalog of human heart-specific enhancers for clinical CHD-related studies. IMPACT: Establishing an efficient way to analyze regulatory regions in CHD is very important. A highly qualified heart-specific enhancer compendium was generated by integrating 148 online ChIP-seq samples. Sixty-seven percent of predicted regulatory sequences have reproducible heart-specific enhancer activity in vivo. Human heart-specific enhancer wf1 regulates the CHD-related FBN1 gene.

Effects of elevated air temperature coupling with soil drought on carbohydrate metabolism and oil synthesis during cottonseed development.

Cotton, as the fifth-largest oilseed crop, often faces the coupling stress of heat and drought. Still, the effects of combined stress on cottonseed oil synthesis and its closely related carbon metabolism are poorly investigated. To this end, experiments were conducted with two cultivars (Sumian 15 and PHY370WR) under two temperature regimes: ambient temperature (AT) and elevated temperature (ET, which was 2.5°C-2.7°C higher than AT) and three water regimes: optimum soil moisture (soil relative water content [SRWC] at 75% ± 5%), and drought (SD) including SRWC 60% ± 5% and SRWC 45% ± 5%, during 2016-2018. Results showed that ET plus SD decreased cottonseed kernel yield, seed index, kernel weight, and kernel percentage more than either single stress. The content of hexoses, the carbon skeleton source for oil synthesis, was decreased by ET while increased by SD. The combined stress increased the hexose content by increasing the activities of sucrose synthase (SuSy, EC 2.4.1.13) and invertase (Inv, EC 3.2.1.26) and upregulating GhSuSy expression; however, hexose content under combined stress was lower than that under SD alone. Increased oil content under SD was attributed to the high phosphoenolpyruvate carboxylase (PEPCase, EC 4.1.1.31), acetyl-CoA carboxylase (ACCase, EC 6.4.1.2), and diacylglycerol acyltransferase (DGAT, EC 2.3.1.20) activities, whereas the opposite effects were seen under ET. Under combined stress, although ACCase activity decreased, PEPCase and DGAT activities, and GhPEPC-1 and GhDGAT-1 expression upregulated, enhancing carbon flow into oil metabolism and triacylglycerol synthesis, ultimately generating higher oil content.

Foliar melatonin stimulates cotton boll distribution characteristics by modifying leaf sugar metabolism and antioxidant activities during drought conditions.

Drought is a severe abiotic stress affecting the plant's antioxidant system and interrupting compatible solute translocation processes, which leads to low productivity. Melatonin acts as a common growth regulator enhancing the plants defense system and regulates sugar metabolism in challenging environments. Melatonin treatments enable plants to be tolerant to abiotic stresses via enhancing their recovery potential, but its impact using various concentrations has not yet been studied in leaf physiological aspects when applied to cotton foliage during their peak flowering and boll loading stage. The overall objective of this research was to facilitate cotton boll distribution characteristics by modifying cotton leaf sugar metabolism and antioxidant activity by applying foliar melatonin (0, 25, 50, and 100 µmol l-1 ) under drought levels with a relative soil water content of 75%, 60%, and 45% ± 5 (FC1, FC2, and FC3, respectively). Higher rates of melatonin application (100 µmol l-1 ) enhanced boll distribution characteristics and controlled the boll shedding rate during drought conditions. An increase in melatonin rates proved to be more helpful in stimulating cotton sympodial leaf physiological attributes, including leaf gas exchange parameters, sugar metabolism, proline content, and antioxidants defense system as compared with less or no melatonin application during all FC conditions and showed the most significant effect at a higher melatonin concentration (M100) at 7-21 DAF. The total proline content and antioxidant activity were enhanced in the M100 treatment during all FC levels, which caused a reduction in the total malondialdehyde (MDA) contents and hydrogen peroxide (H2 O2 ) concentrations in cotton leaves. Moreover, sugar metabolism responsible genes GhSusA and SPS2 showed an upsurge in expression levels and enhanced sucrose degradation in M100 treatments during all FC levels. Furthermore, cotton boll attributes showed also a positive relation with leaf physiological and gas exchange attributes. The results suggested that foliar melatonin application during the flowering initiation stage improved the overall performance and is helpful for cotton crops productivity against drought stress.

Interictal Spike and Loss of Hippocampal Theta Rhythm Recorded by Deep Brain Electrodes during Epileptogenesis.

Epileptogenesis is the gradual dynamic process that progressively led to epilepsy, going through the latent stage to the chronic stage. During epileptogenesis, how the abnormal discharges make theta rhythm loss in the deep brain remains not clear. In this paper, a loss of theta rhythm was estimated based on time-frequency power using the longitudinal electroencephalography (EEG), recorded by deep brain electrodes (e.g., the intracortical microelectrodes such as stereo-EEG electrodes) with monitored epileptic spikes in a rat from the first region in the hippocampal circuit. Deep-brain EEG was collected from the period between adjacent sporadic interictal spikes (lasting 3.56 s-35.38 s) to the recovery period without spikes by videos while the rats were performing exploration. We found that loss of theta rhythm became more serious during the period between adjacent interictal spikes than during the recovery period without spike, and during epileptogenesis, more loss was observed at the acute stage than the chronic stage. We concluded that the emergence of the interictal spike was the direct cause of loss of theta rhythm, and the inhibitory effect of the interictal spike on ongoing theta rhythm was persistent as well as time dependent during epileptogenesis. With the help of the intracortical microelectrodes, this study provides a temporary proof of interictal spikes to produce ongoing theta rhythm loss, suggesting that the interictal spikes could correlate with the epileptogenesis process, display a time-dependent feature, and might be a potential biomarker to evaluate the deficits in theta-related memory in the brain.

Low Temperature Inhibits the Defoliation Efficiency of Thidiazuron in Cotton by Regulating Plant Hormone Synthesis and the Signaling Pathway.

Thidiazuron (TDZ) is the main defoliant used in production to promote leaf abscission for machine-picked cotton. Under low temperatures, the defoliation rate of cotton treated with TDZ decreases and the time of defoliation is delayed, but there is little information about this mechanism. In this study, RNA-seq and physiological analysis are performed to reveal the transcriptome profiling and change in endogenous phytohormones upon TDZ treatment in abscission zones (AZs) under different temperatures (daily mean temperatures: 25 °C and 15 °C). Genes differentially expressed in AZs between TDZ treatment and control under different temperatures were subjected to gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses to compare the enriched GO terms and KEGG pathways between the two temperature conditions. The results show that, compared with the corresponding control group, TDZ induces many differentially expressed genes (DEGs) in AZs, and the results of the GO and KEGG analyses show that the plant hormone signaling transduction pathway is significantly regulated by TDZ. However, under low temperature, TDZ induced less DEGs, and the enriched GO terms and KEGG pathways were different with those under normal temperature condition. Many genes in the plant hormone signal transduction pathway could not be induced by TDZ under low temperature conditions. In particular, the upregulated ethylene-signaling genes and downregulated auxin-signaling genes in AZs treated with TDZ were significantly affected by low temperatures. Furthermore, the expression of ethylene and auxin synthesis genes and their content in AZs treated with TDZ were also regulated by low temperature conditions. The upregulated cell wall hydrolase genes induced by TDZ were inhibited by low temperatures. However, the inhibition of low temperature on genes in AZs treated with TDZ was relieved with the extension of the treatment time. Together, these results indicate that the responses of ethylene and auxin synthesis and the signaling pathway to TDZ are inhibited by low temperatures, which could not induce the expression of cell wall hydrolase genes, and then inhibit the separation of AZ cells and the abscission of cotton leaves. This result provides new insights into the mechanism of defoliation induced by TDZ under low temperature conditions.

Maize ear growth is stimulated at the fourth day after pollination by cell wall remodeling and changes in lipid and hormone signaling.

BACKGROUND: Stimulating maize ear development is an effective way of improving yield. However, limited information is available regarding the regulation of sink strength change from weak to strong at the same position of maize plants. Here, a novel method for stimulating development combined with physiological assays and proteomics was applied to explore the regulation of ear strengthened development. RESULTS: By blocking pollination of the upper ear of maize hybrid Suyu 41, the adjacent lower ear was dramatically stimulated at 4 days after pollination (DAP). Tandem mass tag (TMT)-based proteomics identified 173 differentially expressed proteins (fold change >1.2 or <0.83, P < 0.05) from 7793 total proteins. Gene ontology annotations indicated that several pathways showed noticeable changes, with a preferential distribution to cell wall remodeling, hormone signals and lipid metabolism in the stimulated kernels. Cell wall remodeling was highly mediated by chitinase, exhydrolase II and xyloglucan enotransglucosylase/hydrolase, and accompanied by increased sucrose and glucose content. A series of lipoxygenase proteins were significantly upregulated, causing a significant alteration in lipid metabolism. Hormone signals were influenced by the expression of the proteins involved in indole-3-acetic acid (IAA) transport, zeatin (ZT) biosynthesis and abscisic acid (ABA) signal response, and increased IAA, ZT and ABA content. CONCLUSION: The critical time for understanding the mechanism by which ear growth is stimulated is 4 DAP. Comparative proteomics and physiological analysis revealed that lipid metabolism enhancement, cell wall remodeling and changes in hormone signaling (IAA, ZT and ABA) were all important in stimulating early ear development. Proper regulation of these pathways may improve ear development, resulting in increased maize yield. © 2022 Society of Chemical Industry.

Aerobic exercise ameliorates cardiac hypertrophy by regulating mitochondrial quality control and endoplasmic reticulum stress through M2 AChR.

Aerobic exercise increases M2 AChR, which thus improves cardiac function in cardiovascular disease (CVD) rats. This study aimed to determine whether aerobic exercise could ameliorate pressure overload-induced heart hypertrophy through M2 AChR, and to elucidate the underlying mechanisms of action. Mice were used to establish the myocardial hypertrophy model by transverse aortic constriction (TAC), and subjected to 2, 4, and 8 weeks of moderate-intensity aerobic exercise and choline intervention (14 mg/kg/day). Our results showed that 4 and 8 weeks of exercise and choline intervention reduced excessive mitochondrial fission and autophagy of myocardial mitochondria, thereby improving the ultrastructure and function of mitochondria after TAC. Moreover, 8-week exercise and choline intervention have enhanced parasympathetic function and promoted the expression of M2 AChR. In addition, 8-week exercise and choline intervention also inhibited the protein expression of myocardial MFN2, PERK/eIF2α/ATF4, and NLRP3/caspase-1/IL-1ß signaling pathways, thereby effectively reducing mitochondrial fusion, endoplasmic reticulum stress, and inflammation. Taken together, these data suggest that pressure overload led to cardiac hypertrophy, cardiac dysfunction, and decreased parasympathetic function in cardiac tissues. Aerobic exercise attenuated cardiac dysfunction by modulating the expression of proteins involved in mitochondrial quality control, and induced endoplasmic reticulum stress and inflammation, thereby reducing cardiac hypertrophy and improving cardiac function in impaired heart tissues following TAC, which was likely mediated by M2 AChR activation.

NO-induced vasodilation correlates directly with BP in smooth muscle-Na/Ca exchanger-1-engineered mice: elevated BP does not attenuate endothelial function.

Arterial smooth muscle Na+/Ca2+ exchanger-1 (SM-NCX1) promotes vasoconstriction or vasodilation by mediating, respectively, Ca2+ influx or efflux. In vivo, SM-NCX1 mediates net Ca2+ influx to help maintain myogenic tone (MT) and neuronally activated constriction. SM-NCX1-TG (overexpressing transgenic) mice have increased MT and mean blood pressure (MBP; +13.5 mmHg); SM-NCX1-KO (knockout) mice have reduced MT and MBP (-11.1 mmHg). Endothelium-dependent vasodilation (EDV) is often impaired in hypertension. We tested whether genetically engineered SM-NCX1 expression and consequent BP changes similarly alter EDV. Isolated, pressurized mesenteric resistance arteries with MT from SM-NCX1-TG and conditional SM-NCX1-KO mice, and femoral arteries in vivo from TG mice were studied. Acetylcholine (ACh)-dilated TG arteries with MT slightly more than control or KO arteries, implying that SM-NCX1 overexpression does not impair EDV. In preconstricted KO, but not TG mouse arteries, however, ACh- and bradykinin-triggered vasodilation was markedly attenuated. To circumvent the endothelium, phenylephrine-constricted resistance arteries were tested with Na-nitroprusside [SNP; nitric oxide (NO) donor] and cGMP. This endothelium-independent vasodilation was augmented in TG but attenuated in KO arteries that lack NCX1-mediated Ca2+ clearance. Baseline cytosolic Ca2+ ([Ca2+]cyt) was elevated in TG femoral arteries in vivo, supporting the high BP; furthermore, SNP-triggered [Ca2+]cyt decline and vasodilation were augmented as NO and cGMP promote myocyte polarization thereby enhancing NCX1-mediated Ca2+ efflux. The TG mouse data indicate that BP elevation does not attenuate endothelium-dependent vasodilation. Thus, in essential hypertension and many models the endothelial impairment that supports the hypertension apparently is not triggered by BP elevation but by extravascular mechanisms.NEW & NOTEWORTHY Endothelium-dependent, ACh-induced vasodilation (EDV) is attenuated, and arterial myocyte Na+/Ca2+ exchangers (NCX1) are upregulated in many forms of hypertension. Surprisingly, mildly hypertensive smooth muscle-specific (SM)-NCX1 transgenic mice exhibited modestly enhanced EDV and augmented endothelium-independent vasodilation (EIV). Conversely, mildly hypotensive SM-NCX1-knockout mice had greatly attenuated EIV. These adaptations help compensate for NCX1 expression-induced alterations in cytosolic Ca2+ and blood pressure (BP) and belie the view that elevated BP, itself, causes the endothelial dysregulation in hypertension.

TAT delivery of a PTEN peptide inhibitor has direct cardioprotective effects and improves outcomes in rodent models of cardiac arrest.

We have recently shown that pharmacologic inhibition of PTEN significantly increases cardiac arrest survival in a mouse model, however, this protection required pretreatment 30 min before the arrest. To improve the onset of PTEN inhibition during cardiac arrest treatment, we have designed a TAT fused cell-permeable peptide (TAT-PTEN9c) based on the C-terminal PDZ binding motif of PTEN for rapid tissue delivery and protection. Western blot analysis demonstrated that TAT-PTEN9c peptide significantly enhanced Akt activation in mouse cardiomyocytes in a concentration- and time-dependent manner. Mice were subjected to 8 min asystolic arrest followed by CPR, and 30 mice with successful CPR were then randomly assigned to receive either saline or TAT-PTEN9c treatment. Survival was significantly increased in TAT-PTEN9c-treated mice compared with that of saline control at 4 h after CPR. The treated mice had increased Akt phosphorylation at 30 min resuscitation with significantly decreased sorbitol content in heart or brain tissues and reduced release of taurine and glutamate in blood, suggesting improved glucose metabolism. In an isolated rat heart Langendorff model, direct effects of TAT-PTEN9c on cardiac function were measured for 20 min following 20 min global ischemia. Rate pressure product was reduced by >20% for both TAT vehicle and nontreatment groups following arrest. Cardiac contractile function was completely recovered with TAT-PTEN9c treatment given at the start of reperfusion. We conclude that TAT-PTEN9c enhances Akt activation and decreases glucose shunting to the polyol pathway in critical organs, thereby preventing osmotic injury and early cardiovascular collapse and death.NEW & NOTEWORTHY We have designed a cell-permeable peptide, TAT-PTEN9c, to improve cardiac arrest survival. It blocked endogenous PTEN binding to its adaptor and enhanced Akt signaling in mouse cardiomyocytes. It improved mouse survival after cardiac arrest, which is related to improved glucose metabolism and reduced glucose shunting to sorbitol in critical organs.

An analysis of perioperative hidden blood loss in femoral intertrochanteric fractures: bone density is an important influencing factor.

BACKGROUND: To explore the influencing factors of perioperative hidden blood loss in intertrochanteric fractures. METHOD: We undertook a retrospective analysis from January 2016 to October 2019. Clinical data of 118 patients with intertrochanteric fractures were included. Hidden blood loss was calculated from the haematocrit changes before and after surgery using the Gross equation based on height, weight, and haematocrit (HCT) changes before and after surgery. Patients' gender, age, presence of underlying diseases, fracture types, anaesthesia methods, time from injury to surgery, administration of antiplatelet drugs within 6 months before surgery, use of anticoagulant drugs after surgery, and bone density were statistically analysed. Factors having an effect on hidden blood loss were screened out. Then, hidden blood loss was used as the dependent variable, and each influencing factor was used in turn as the independent variable. Multivariate linear regression analysis was employed to analyse the related risk factors that affect hidden blood loss during the perioperative period of patients with intertrochanteric fractures. RESULT: The apparent blood loss during the operation was 203.81 ±105. 51 ml, and the hidden blood loss was 517.55±191.47 ml. There were significant differences in the hidden blood loss of patients with different fracture types (stable vs unstable), anaesthesia methods (general anaesthesia vs intraspinal anaesthesia), antiplatelet or postoperative anticoagulant drugs, and bone densities (P< 0.05). 05). Multiple linear regression analysis showed that internal fixation, age, fracture type, anaesthesia method, anticoagulant application, and bone density were related risk factors that affected hidden blood loss during the surgical treatment of intertrochanteric fractures. CONCLUSION: Hidden blood loss is the main cause of perioperative blood loss in intertrochanteric fractures, and the risk factors for hidden blood loss include internal fixation, fracture type (e.g., unstable), anaesthesia (e.g., intraspinal), and use of anticoagulant drugs. Specifically, we found that low bone density was a risk factor for hidden blood loss. It is not reliable to use apparent blood loss as the basis for fluid replacement and transfusion. We must fully consider the existence of hidden blood loss and intervene as soon as possible to prevent complications. LEVEL OF EVIDENCE: III.