Spur development and evolution: An update.

Floral spurs, widely recognized as a classic example of key morphological and functional innovation and thought to have promoted the origin and adaptive evolution of many flowering plant lineages, have attracted the attention of researchers for centuries. Despite this, the mechanisms underlying the development and evolution of these structures remain poorly understood. Recent studies have discovered the phytohormones and transcription factor genes that play key roles in regulating patterns of cell division and cell expansion during spur morphogenesis. Spur morphogenesis was also found to be tightly linked with the programs specifying floral zygomorphy, floral organ identity determination, and nectary development. Independent origins and losses of spurs in different flowering plant lineages, therefore, may be attributed to changes in the spur program and/or its upstream ones.

Comparative analysis of e-cigarette prevalence and influencing factors among adolescents in Jiangsu Province, China.

Objective: The objectives of this study were to investigate electronic cigarette (e-cigarette) and cigarette use in Jiangsu Province, China, by analyzing the two-year trends of e-cigarette using and to explore the factors influencing the experimentation and use of e-cigarettes. Methods: We conducted a cross-sectional study following the standard methodology of the Global Youth Tobacco Survey in 2019 and 2021. A three-stage cluster sampling design was applied. Eighty-two schools in 14 districts (counties) in Jiangsu Province were surveyed. All computations were performed using the SPSS 21.0 complex samples procedure. Multivariate logistic regression was used to explore the factors influencing e-cigarette experimentation and use. Results: A total of 12,410 and 12,880 students were surveyed in 2019 and 2021, respectively. E-cigarette experimentation increased from 9.34% in 2019 to 13.07% in 2021 (P < 0.001). E-cigarette use increased from 2.23% in 2019 to 3.74% in 2021 (P < 0.001). The main factors associated with e-cigarette use were cigarette experimentation (OR = 2.700, P < 0.001); male gender (OR = 1.416, P = 0.011); junior high school students (OR = 1.551, P = 0.005) and vocational high school students (OR = 1.644, P = 0.001); more pocket money per week (OR1 = 1.214, P = 0.187; OR2 = 1.686, P = 0.001); exposure to second-hand smoke (SHS) at home (OR = 1.239, P < 0.001); exposure to e-cigarette advertising (OR = 1.855, P < 0.001); believe SHS is harmful (OR = 0.933, P = 0.026); closest friends smoking (OR = 2.501, P < 0.001); believe smoking makes youth look more attractive (OR1 = 1.469, P = 0.040; OR2 = 1.305, P = 0.049); believe tobacco helps youth feel more comfortable in social situations (OR1 = 2.161, P < 0.001; OR2 = 1.635, P = 0.001); will use an e-cigarette product if offered by best friends (OR = 1.322, P < 0.001); intend to use an e-cigarette product in the next 12 months (OR = 1.486, P < 0.001). Conclusion: E-cigarette use among adolescents has been on the rise in recent years. E-cigarette use is associated with past cigarette use and a strong desire to smoke. It is crucial to take health education and tobacco control efforts to reduce adolescents' e-cigarette use rate.

Doxorubicin suppresses chondrocyte differentiation by stimulating ROS production.

BACKGROUND: Doxorubicin (DOX) is widely used as an effective chemotherapy agent in human cancer. Our study aimed to explore the specific mechanism of DOX in osteoarthritis (OA). METHODS: A mouse OA model was established by destabilizing the medial meniscus (DMM), and the role of DOX was determined by intraperitoneally injecting 5 or 10 mg/kg DOX. The expression of collagen type-II (Col-2) was detected by immunohistochemistry staining, and the expression of plasma interleukin (IL)-6 (IL-6), IL-1beta (IL-1ß), and tumor necrosis factor (TNF)-alpha (TNF-α) was evaluated by specific ELISA kits, and the expression of Sry-related HMG box 9 (SOX-9) was detected by western blot. Bone marrow mesenchymal stem cells (BMMSCs) were used to explore the mechanism of DOX in vitro. Reactive oxygen species (ROS) production was determined by flow cytometry. Cell viability was measured by Cell Counting Kit-8 (CCK-8) assay. Chondrocyte differentiation was evaluated by Alcian blue staining assay. The expression of chondrocyte differentiation-related markers was detected by quantitative reverse transcription-polymerase chain reaction (qRT-PCR). RESULTS: DOX exposure exacerbated OA progression and inhibited chondrocyte differentiation of BMMSCs. DOX also increased ROS production in BMMSCs. Meanwhile, DOX further increased the elevation of plasma IL-6, IL-1ß and TNF-α induced by DMM and obviously reduced the expression of chondrocyte differentiation-related markers, including collagen type II a1 (Col2A1), collagen type X alpha 1 (Col10A1), and aggrecan. Moreover, ROS scavengers NAC and MitoQ efficiently alleviated DOX toxicity, including ROS production and chondrocyte differentiation in BMMSCs. CONCLUSION: Our study revealed that DOX suppressed chondrocyte differentiation by stimulating ROS production, providing a novel theoretical strategy for the clinical treatment of OA caused by DOX.

Dual Function of PI(4,5)P2 in Insulin-Regulated Exocytic Trafficking of GLUT4 in Adipocytes.

Phosphoinositides are important signaling molecules involved in the regulation of vesicular trafficking. It has been implicated that phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2] is involved in insulin-regulated GLUT4 translocation in adipocytes. However, it remains unclear where and how PI(4,5)P2 regulates discrete steps of GLUT4 vesicle translocation in adipocytes, especially on the exocytic arm of regulation. Here, we employed optogenetic tools to acutely control the PI(4,5)P2 metabolism in living cells. By combination of TIRFM imaging, we were able to monitor the temporal-spatial-dependent PI(4,5)P2 regulation on discrete steps of GLUT4 translocation in adipocytes. We found that the plasma membrane localized PI(4,5)P2 is crucial for proper insulin signaling propagation and for insulin-stimulated GLUT4 vesicle translocation in 3T3-L1 adipocytes. Global depletion of PI(4,5)P2 on the cell surface blunted insulin-stimulated Akt phosphorylation and abolished insulin effects in promotion of the docking and fusion of GLUT4 vesicle with the plasma membrane. Furthermore, by development of a novel optogenetic module to selectively modulate PI(4,5)P2 levels on the GLUT4 vesicle docking site, we identified an important regulatory role of PI(4,5)P2 in controlling of vesicle docking process. Local depletion of PI(4,5)P2 at the vesicle docking site promoted GLUT4 vesicle undocking, diminished insulin-stimulated GLUT4 vesicle docking and fusion, but without perturbation of insulin signaling propagation in adipocytes. Our results provide strong evidence that cell surface PI(4,5)P2 plays two distinct functions on regulation of the exocytic trafficking of GLUT4 in adipocytes. PI(4,5)P2 not only regulates the proper activation of insulin signaling in general but also controls GLUT4 vesicle docking process at the vesicle-membrane contact sites.

Proximity proteomics identifies novel function of Rab14 in trafficking of Ebola virus matrix protein VP40.

Ebola virus is a member of Filoviridae family of viruses that causes fetal hemorrhagic fever in human. Matrix protein VP40 of the Ebola virus is involved in multiple stages of viral maturation processes. In order to fully understand the interacting partners of VP40 in host cells, we applied proximity-dependent biotin-identification (BioID) approach to systematically screen for potential proteins at different time points of VP40 expression. By immunoprecipitation and subsequent proteomics analysis, we found over 100 candidate proteins with various cellular components and molecular functions. Among them, we identified Rab14 GTPase that appears to function at the late stage of VP40 expression. Imaging studies demonstrated that VP40 and Rab14 have substantial colocalization when expressed in HeLa cells. Overexpression of the dominant-negative Rab14(S25N) diminished the plasma membrane (PM) localization of VP40. In addition, we found that secreted VP40 protein can be endocytosed into Rab14 positive compartments. In summary, our study provides evidence that Rab14 is a novel regulator of the intracellular trafficking of Ebola virus matrix protein VP40 in HeLa cells.

Phospholipase D as a key modulator of cancer progression.

The phospholipase D (PLD) family has a ubiquitous expression in cells. PLD isoforms (PLDs) and their hydrolysate phosphatidic acid (PA) have been demonstrated to engage in multiple stages of cancer progression. Aberrant expression of PLDs, especially PLD1 and PLD2, has been detected in various cancers. Inhibition or elimination of PLDs activity has been shown to reduce tumour growth and metastasis. PLDs and PA also serve as downstream effectors of various cell-surface receptors, to trigger and regulate propagation of intracellular signals in the process of tumourigenesis and metastasis. Here, we discuss recent advances in understanding the functions of PLDs and PA in discrete stages of cancer progression, including cancer cell growth, invasion and migration, and angiogenesis, with special emphasis on the tumour-associated signalling pathways mediated by PLDs and PA and the functional importance of PLDs and PA in cancer therapy.

Icariin Alleviates IL-1ß-Induced Matrix Degradation By Activating The Nrf2/ARE Pathway In Human Chondrocytes.

OBJECTIVE: Osteoarthritis (OA) is characterized by progressive matrix destruction of articular cartilage. This study aimed to investigate the potential antioxidative and chondroprotective effects and underlying mechanism of Icariin (ICA) in interleukin-1 beta (IL-1ß)-induced extracellular matrix (ECM) degradation of OA cartilage. METHODS: Human chondrocyte cell line HC-A was treated with different doses of ICA, and then MTT assay and PI staining were used to estimate ICA-induced chondrocyte apoptosis. Intracellular ROS and superoxide dismutase (SOD) and glutathione peroxidase (GPX) were measured after treatment by IL-1ß with or without ICA. The mRNA and protein expression levels of redox transcription factor Nrf2 and the downstream effector SOD-1, SOD-2, NQO-1 and HO-1 were assayed to explore the detailed mechanism by which ICA alleviates ECM degradation. Finally, to expound the role of Nrf2 in ICA-mediated chondroprotection, we specifically depleted Nrf2 in human chondrocytes and then pretreated them with ICA followed by IL-1ß. RESULTS: ICA had no cytotoxic effects on human chondrocytes and 10-9 M was selected as the optimum concentration. ROS induced by IL-1ß could drastically activate matrix-degrading proteases and ICA could significantly rescue the matrix degradation and excess ROS generation caused by IL-1ß. We observed that ICA activated the Nrf2/ARE pathway, consequently upregulating the generation of GPX and SOD. Ablation of Nrf2 abrogated the chondroprotective and antioxidative effects of ICA in IL-1ß-treated chondrocytes. CONCLUSION: ICA alleviates IL-1ß-induced matrix degradation and eliminates ROS by activating the Nrf2/ARE pathway.

A novel core-shell nanofiber drug delivery system intended for the synergistic treatment of melanoma.

Here, we introduce core-shell nanofibers based on chitosan (CS)-loaded poly (ε-caprolactone) (PCL) shell and 5-fluorouracil (5-FU)-loaded Poly(N-vinyl-2-pyrrolidone) (PVP) core for synergistic therapy of melanoma skin cancer. The yielded nanofibers exhibited an average diameter of 503 nm with high drug-encapsulating efficiency and good mechanical properties. Moreover, the burst release of 5-FU significantly inhibited melanoma skin cancer cells (B16F10 cells), and the sustained release of CS exhibited "remedying effects" on normal skin cells (L929 cells) after suffering adverse effects from 5-FU treatment. For the B16F10 cells, the early apoptosis cells increased from 0.8% to 62.2% after being treated with blended films loaded with 5-FU (2 wt%) for 24 h; for the L929 cells, the vital cells increased from 68.9% to 77.0%, and the early apoptosis of stage cells decreased from 12.3% to 10.9% after being treated with blended films with CS (8 wt%) for 24 h. In conclusion, the results introduced in this work can be a promising strategy for cancer treatment and possesses synergism potential to broaden an avenue for chemotherapeutic therapy with minimum adverse effects on normal cells.

Multi-color live-cell super-resolution volume imaging with multi-angle interference microscopy.

Imaging and tracking of near-surface three-dimensional volumetric nanoscale dynamic processes of live cells remains a challenging problem. In this paper, we propose a multi-color live-cell near-surface-volume super-resolution microscopy method that combines total internal reflection fluorescence structured illumination microscopy with multi-angle evanescent light illumination. We demonstrate that our approach of multi-angle interference microscopy is perfectly adapted to studying subcellular dynamics of mitochondria and microtubule architectures during cell migration.

Rab8A regulates insulin-stimulated GLUT4 translocation in C2C12 myoblasts.

Rab proteins are important regulators of GLUT4 trafficking in muscle and adipose cells. It is still unclear which Rabs are involved in insulin-stimulated GLUT4 translocation in C2C12 myoblasts. In this study, we detect the colocalization of Rab8A with GLUT4 and the presence of Rab8A at vesicle exocytic sites by TIRFM imaging. Overexpression of dominant-negative Rab8A (T22N) diminishes insulin-stimulated GLUT4 translocation, while constitutively active Rab8A (Q67L) augments it. In addition, knockdown of Rab8A inhibits insulin-stimulated GLUT4 translocation, which is rescued by replenishment of RNAi-resistant Rab8A. Together, these results indicate an indispensable role for Rab8A in insulin-regulated GLUT4 trafficking in C2C12 cells.

Differential requirement for N-ethylmaleimide-sensitive factor in endosomal trafficking of transferrin receptor from anterograde trafficking of vesicular stomatitis virus glycoprotein G.

N-ethylmaleimide-sensitive fusion factor (NSF) is an ATPase that plays a crucial role in vesicular transport. Here, we examined the effects of NSF knockdown on Golgi structure and different vesicle trafficking pathways in mammalian cells. NSF knockdown caused Golgi fragmentation and abolished transferrin receptor exocytosis, defects that were rescued by RNAi-resistant NSF. Strikingly, NSF deficiency in HeLa cells barely affected cell viability, anterograde trafficking of vesicular stomatitis virus glycoprotein G and transferrin endocytosis. These results confirm the central role of NSF in Golgi structure and reveal differential requirement of NSF for exocytic recycling and constitutive trafficking pathways.

Application of 3D Printing in the Surgical Planning of Trimalleolar Fracture and Doctor-Patient Communication.

To evaluate the effect of 3D printing in treating trimalleolar fractures and its roles in physician-patient communication, thirty patients with trimalleolar fractures were randomly divided into the 3D printing assisted-design operation group (Group A) and the no-3D printing assisted-design group (Group B). In Group A, 3D printing was used by the surgeons to produce a prototype of the actual fracture to guide the surgical treatment. All patients underwent open reduction and internal fixation. A questionnaire was designed for doctors and patients to verify the verisimilitude and effectiveness of the 3D-printed prototype. Meanwhile, the operation time and the intraoperative blood loss were compared between the two groups. The fracture prototypes were accurately printed, and the average overall score of the verisimilitude and effectiveness of the 3D-printed prototypes was relatively high. Both the operation time and the intraoperative blood loss in Group A were less than those in Group B (P < 0.05). Patient satisfaction using the 3D-printed prototype and the communication score were 9.3 ± 0.6 points. A 3D-printed prototype can faithfully reflect the anatomy of the fracture site; it can effectively help the doctors plan the operation and represent an effective tool for physician-patient communication.

Optogenetic activation reveals distinct roles of PIP3 and Akt in adipocyte insulin action.

Glucose transporter 4 (GLUT4; also known as SLC2A4) resides on intracellular vesicles in muscle and adipose cells, and translocates to the plasma membrane in response to insulin. The phosphoinositide 3-kinase (PI3K)-Akt signaling pathway plays a major role in GLUT4 translocation; however, a challenge has been to unravel the potentially distinct contributions of PI3K and Akt (of which there are three isoforms, Akt1-Akt3) to overall insulin action. Here, we describe new optogenetic tools based on CRY2 and the N-terminus of CIB1 (CIBN). We used these 'Opto' modules to activate PI3K and Akt selectively in time and space in 3T3-L1 adipocytes. We validated these tools using biochemical assays and performed live-cell kinetic analyses of IRAP-pHluorin translocation (IRAP is also known as LNPEP and acts as a surrogate marker for GLUT4 here). Strikingly, Opto-PIP3 largely mimicked the maximal effects of insulin stimulation, whereas Opto-Akt only partially triggered translocation. Conversely, drug-mediated inhibition of Akt only partially dampened the translocation response of Opto-PIP3 In spatial optogenetic studies, focal targeting of Akt to a region of the cell marked the sites where IRAP-pHluorin vesicles fused, supporting the idea that local Akt-mediated signaling regulates exocytosis. Taken together, these results indicate that PI3K and Akt play distinct roles, and that PI3K stimulates Akt-independent pathways that are important for GLUT4 translocation.

[Proliferation and chondrogenic differentiation of precartilaginous stem cells in self-assembling peptide nanofiber scaffolds].

OBJECTIVE: To construct a new type of self-assembling peptide nanofiber scaffolds-RGDmx, and to study the cell compatibility of the new scaffolds and the proliferation and chondrogenic differentiation of precartilaginous stem cells (PSCs) in scaffolds. METHODS: PSCs were separated and purified from newborn Sprague Dawley rats by magnetic activated cell sorting and indentified by immunohistochemistry and immunofluorescent staining. The RGDmx were constructed by mixing KLD-12 and KLD-12-PRG at volume ratio of 1:1. PSCs at passage 3 were seeded into the KLD-12 scaffold (control group) and RGDmx scaffold (experimental group). The proliferation of PSCs in 2 groups were observed with the method of cell counting kit (CCK)-8 after 1, 3, 7, and 14 days after culture. The RGDmx were constructed by mixing KLD-12-PRG and KLD-12 at different volume ratios of 0, 20%, 40%, 60%, 80%, and 100% and the proliferation of PSCs was also observed. The complete chondrogenic medium (CCM) was used to induce chondrogenic differentiation of PSCs in different scaffolds. The differentiation of PSCs was observed by toluidine blue staining and RT-PCR assay. RESULTS: PSCs were separated and purified successfully, which were identified by immunohistochemistry and immunofluorescent staining methods. The results of CCK-8 showed that the absorbance (A) value in the experimental group increased gradually and reached the highest at 7 days; the A value in the experimental group was significantly higher than that in the control group at 7 days and 14 days (P < 0.05). Meanwhile, the A value in the RGDmx scaffold with a volume ratio of 40% was significantly higher than those in others (P < 0.05). After 14 days of induction culture with CCM, the toluidine blue staining results were positive in 2 groups; the results of RT-PCR showed that the expression levels of collagen type II and the aggrecan in the experimental group were significantly higher than those in the control group (P < 0.05). CONCLUSION: The self-assembling peptide nanofiber scaffold-RGDmx is an ideal scaffold for tissue engineer because it has good cell compatibility and more effective properties of promoting the differentiation of PSCs to chondrocytes.