2p Levels Research Articles

Effects of Sr and Mg doping on elastic, mechanical, and optical properties of hydroxyapatite: A first-principles study

Hydroxyapatite (HAp), with the chemical formula Ca10(PO4)6(OH)2, is a bioactive ceramic material typically used in the treatment of bone defects owing to the excellent biocompatibility and the ability to bond with bone tissues. Mechanical properties of HAp have drawn pronounced attention because of the crucial roles in the medical applications. Based on density functional theory (DFT), this work reports the structural, formation energy, mechanical, Vickers hardness, electronic properties, and optical properties of hydroxyapatite (HAp), strontium-substituted HAp (Sr-HAp), and magnesium-substituted HAp (Mg-HAp). The results reveal that the Sr2+ and Mg2+ ions mainly replace the Ca2+ ion at the Ca-1 site in HAp. Resistance to hydrostatic compression followed the order Mg-HAp > HAp > Sr-HAp. Sr-HAp has the capability to enhance thermal shock resistance and lattice thermal conductivity. In addition, the electronic properties of HAp change upon substitutional Sr2+ and Mg2+ doping. In comparison with pristine HAp, the energy gap of Sr-doped HAp relatively increases, whereas that of Mg-doped HAp decreases. Nevertheless, both Sr-HAp and Mg-HAp remain insulators. Intriguingly, Sr-HAp possesses the improved hardness by 11.31 % owing to the hybridization of the Sr (4p) and O (2p) states, which contributed to its high shear modulus and high hardness. Beyond that, we further investigate their optical properties. The presence of Mg states at approximately 10 eV in the conduction band leads to enhanced absorption within the 14 – 20 eV for Mg-doped HAp. Similarly, the presence of a deep Sr(4p) level in Sr-HAp amplifies absorption within the 20–25 eV range. These findings have raised a potential avenue for selectively boosting the optical absorption of HAp, thus improving its photocatalytic properties.

Dual-ended pumped high-power 915 nm Pr3+:LiYF4 laser and power scaling under energy levels cascade

We reported a high-power 915 nm Pr3+:LiYF4 (Pr:YLF) laser dual-ended pumped by laser diodes (LDs). The maximum output power of the laser was 3.39 W with a slope efficiency of 19.8 %. The fluctuation range of the laser wavelength was less than 0.58 nm. As far as we know, this is the highest power at 915 nm for LD-pumped Pr:YLF lasers to date. To eliminate the power saturation phenomenon and further improve the laser output power, we proposed a simple and effective method, i.e., laser energy levels cascade. Based on the experimental data, we calculated the populations of 3P0 and 1G4 energy levels in Pr:YLF crystal during laser cascading and developed two different models to verify the feasibility of the laser cascade mechanism. Moreover, the laser cascade could be realized merely by designing the lens film without introducing other devices, which provided a simple and effective solution for developing high-performance lasers.

Triggered lattice-oxygen oxidation with active-site generation and self-termination of surface reconstruction during water oxidation.

To master the activation law and mechanism of surface lattice oxygen for the oxygen evolution reaction (OER) is critical for the development of efficient water electrolysis. Herein, we propose a strategy for triggering lattice-oxygen oxidation and enabling non-concerted proton-electron transfers during OER conditions by substituting Al in La0.3Sr0.7CoO3-δ. According to our experimental data and density functional theory calculations, the substitution of Al can have a dual effect of promoting surface reconstruction into active Co oxyhydroxides and activating deprotonation on the reconstructed oxyhydroxide, inducing negatively charged oxygen as an active site. This leads to a significant improvement in the OER activity. Additionally, Al dopants facilitate the preoxidation of active cobalt metal, which introduces great structural flexibility due to elevated O 2p levels. As OER progresses, the accumulation of oxygen vacancies and lattice-oxygen oxidation on the catalyst surface leads to the termination of Al3+ leaching, thereby preventing further reconstruction. We have demonstrated a promising approach to achieving tunable electrochemical reconstruction by optimizing the electronic structure and gained a fundamental understanding of the activation mechanism of surface oxygen sites.

Comprehensive structural and surface investigation of Sb2Se3 thin-films

Earth-abundant antimony selenide (Sb2Se3) is a promising material for the thin-film photovoltaic applications due to its desirable optoelectronic properties and suitable band gap. In this work, we present a comprehensive study on the structural and surface properties of Sb2Se3 thin-films for the potential applications in solar cells. The Sb2Se3 samples were grown on Si (100) substrate and at different substrate temperatures using radio frequency (RF) magnetron sputtering. The XRD diffractogram exhibits that Sb2Se3 is the predominant phase in all the samples, whereas the TEM measurements confirm the nanocrystalline nature of the samples. Raman spectroscopy measurements in the range of 30–500 cm−1 displays the Raman shifts at 148, 190 and 206 cm−1, which confirms the presence of the Sb2Se3 phase. The average surface roughness and grain size were obtained via surface topography with the help of the high-resolution AFM images. The EDS spectra revealed the presence of both Se and Sb as constituent elements in all the samples. The deconvolution of XPS spectra of Se 3p and Sb 3d core level disclose the Sb+3 and Se−2 oxidation state and further confirms the presence of Sb2Se3 phase. The XPS and EDS measurements predict that there is loss of Se during the deposition and it could have adverse effects on the performance of Sb2Se3 solar cell devices.

Pr3+-Er3+ co-doped Ba3.75Gd0.833Nb10O30 glass-ceramics for tunable luminescence, optical anti-counterfeiting and temperature sensing

Pr3+-Er3+ co-activated glass-ceramics containing Ba3.75Gd0.833Nb10O30 crystalline phase were prepared as a multifunctional material. The optimum heat treatment condition was determined to be 750 °C/90 min, as this condition is most favorable for luminescence. As the Pr3+ concentration increases, the emissions of 3P0 and 1D2 energy levels show different trends, leading to a shift in luminescence from orange to yellow. With the introduction of Er3+, the co-doped sample achieves orange-yellow-green tunable luminescence. The 0.3%Pr3+-0.3%Er3+ co-doped sample exhibits alternating yellow-orange-green luminescence during continuous excitation in the range of 250–500 nm, which has potential applications in optical anti-counterfeiting. In the temperature interval of 298–458 K, the maximum temperature sensitivities based on the NTCLs of Pr3+ and Er3+ were 0.82 × 10−2 K−1 (Sa) and 1.40 % K−1 (Sr). Meanwhile, the thermal repeatability ratio is higher than 92.3 %, which proved that it is a potential temperature sensing material. In addition, the concentration quenching, energy transfer and luminescence phenomena involved were analyzed in depth and their mechanisms were explained.

Study of new carbonitrile as an anti-muscular dystrophy agent: Crystal, vibrational spectroscopy, molecular docking, electronic and intermolecular interaction investigations by the DFT method

Muscular dystrophy, a genetically induced and highly lethal disease, necessitates urgent curative solutions. Many therapeutic drugs for this condition incorporate heterocyclic compounds. This study presents the synthesis, spectral analysis (FT-IR, 1HNMR , 13CNMR , HSQC, Mass), X-ray crystallography, molecular structure examination, electronic properties, and in-silico investigations of 3-((4-nitrophenyl)(p-tolylamino)methyl)-1H-indole-5-carbonitrile (TNIC) as a potent anti-muscular dystrophy drug. Density function theory (DFT) at the B3LYP-D3(BJ)/6-311++ (2d, 2p) level provided geometric and reactivity parameters. Computational studies explored natural bond orbitals, nonlinear optics properties, frontier molecular orbitals, quantum descriptors, and molecular electrostatic potential. Calculated wavelengths closely matched experimental values for TNIC. Molecular docking results indicated anti-muscle dystrophy effects against muscle dystrophy proteins (2VD5 and 2KKQ) with binding energies of −8.5 kcal/mol and −8.2 kcal/mol, surpassing the standard drug Deflazacort. This study highlights TNIC's significant biological activity against muscular dystrophy.

Experimental validation of particle-in-cell/Monte Carlo collisions simulations in low-pressure neon capacitively coupled plasmas

Plasma simulations are powerful tools for understanding fundamental plasma science phenomena and for process optimisation in applications. To ensure their quantitative accuracy, they must be validated against experiments. In this work, such an experimental validation is performed for a one dimensional in space and three dimensional in velocity space particle-in-cell simulation complemented with the Monte Carlo treatment of collision processes of a capacitively coupled radio frequency plasma driven at 13.56 MHz and operated in neon gas. In a geometrically symmetric reactor the electron density in the discharge centre and the spatio-temporal distribution of the electron impact excitation rate from the ground into the Ne 2p1 level are measured by a microwave cutoff probe and phase resolved optical emission spectroscopy, respectively. The measurements are conducted for electrode gaps between 50 mm and 90 mm, neutral gas pressures between 20 mTorr and 50 mTorr, and peak-to-peak values of the driving voltage waveform between 250 V and 650 V. Simulations are performed under identical discharge conditions. In the simulations, various combinations of surface coefficients characterising the interactions of electrons and heavy particles with the anodised aluminium electrode surfaces are adopted. We find, that the simulations using a constant effective heavy particle induced secondary electron (SE) emission coefficient of 0.3 and a realistic electron–surface interaction model (which considers energy-dependent and material specific elastic and inelastic electron reflection, as well as the emission of true SEs from the surface) yield results which are in good quantitative agreement with the experimental data.

Modulating the antithermal-quenching of praseodymium-activated phosphor by the position of intervalence charge transfer state

So far, overcoming thermal quenching remains a huge challenge in the application of phosphor materials. The intervalence charge transfer (IVCT) state has an inestimable role in the compensation of antithermal-quenching effects and is widely used in the research of applications in optical temperature sensing, yet little study has been reported on its modulation of thermal quenching properties. In this contribution, the thermal quenching properties of praseodymium-activated solid-solution substituted GdNb1-xTaxO4 phosphors were investigated systematically for the inaugural time from the perspective of IVCT energy level positions. According to the empirical formula, the IVCT level positions in the phosphor increase sequentially from 32960.71 cm−1 to 33442.15 cm−1, the DFT calculates the extension of the substrate band gap from 3.6408 eV to 4.3066 eV, and the contributing energy level of the conduction band is determined. The variation in the position of the IVCT energy level explains the alteration of the luminescence intensity at room temperature for different composition phosphor 3P0 and 1D2 energy levels. More particularly, it was analyzed that in the variable temperature spectra, x = 0–0.75 exhibited different degrees of efficient antithermal-quenching properties at 303–523 K, while no antithermal-quenching was presented at x = 1. By analyzing the IVCT energy level position and other influencing factors such as band gap, the feasibility of the IVCT energy level position as a competing model for the compensation and quenching channels is established, and the internal mechanism of regulating thermal quenching property is revealed. Effective control of the phosphor resistance to thermal quenching performance was achieved, which directly determines whether enhanced or diminished thermal quenching can be obtained. This finding provides a new effective strategy for the tuning of thermal quenching luminescence of Pr3+-doped Nb/Ta system phosphors.

Investigation on the kinetics of a diode-pumped plasma-jet type metastable argon laser

Diode-pumped rare gas lasers (DPRGLs) have the potential for high-energy laser output with high beam quality. The metastable concentration >1014 cm−3 and pump intensity >10 kW/cm2 are required in developing high-power and efficient DPRGLs. However, the kinetics of 1s and 2p levels (Paschen notation) under these conditions is unclear yet, particularly regarding the adverse effects of interference energy levels (e.g., 1s4 and 2p1–2p8). This study addresses this gap by measuring the number densities of 1s and 2p levels in a diode-pumped plasma jet metastable argon laser. The experiment was conducted with a much higher number density of 1014 cm−3 and a higher pump intensity of 12 kW/cm2 than our previous works. The results indicate that the adverse effect of 1s4 accumulation could be partially compensated, and the relative population distribution of 2p energy levels remained unchanged. However, the high gas temperature (>1000 K) caused a significant negative impact of high 2p levels (2p1–2p8), and the air environment weakened the effect of He collision relaxation.

MiR-708–3p promotes gastric cancer progression through downregulating ETNK1

MicroRNAs (miRNAs) are small, evolutionarily conserved, non-coding RNAs playing a role in the proliferation, metastasis, apoptosis, chemo-sensitivity, and chemo-resistance of gastric cancer, as well as the stemness of gastric cancer stem cells. miR-708–3p induces gastric cancer cell chemo-resistance, but its actual role in gastric cancer progression remains unclear. This paper shows that miR-708–3p is upregulated in gastric cancer samples and that a high miR-708–3p expression in gastric cancer patients is associated with poor overall survival. Our functional study results indicate that miR-708–3p overexpression promotes gastric cancer cell proliferation and migration, inhibits cell apoptosis, and facilitates the transition from the G0/G1 to the G2/M phase. Furthermore, reducing miR-708–3p levels yielded opposite effects. Next, our in vivo experiments revealed that miR-708–3p advanced gastric cancer cell growth in nude mice. The underlying mechanism was the regulation of ethanolamine kinase 1 (ETNK1) expression by miR-708–3p, which bound to the 3′UTR of the ETNK1 gene in gastric cancer cells. Finally, the recovery assay results showed that ETNK1 overexpression could slow miR-708-3p-induced gastric cancer progression. In conclusion, we identified a new miR-708–3p/ETNK1 pathway involved in gastric cancer progression. These results may offer new targets for gastric cancer therapy and markers for gastric cancer prognosis.

MiR-224–5p acts as a tumour suppressor and reverses the resistance to BRAF inhibitor in melanoma through directly targeting PAK4 to block the MAPK pathway

miR-224–5p has been shown to play both an oncogene and tumour suppressor role in many human tumours. However, the role and molecular mechanism of miR-224–5p in cutaneous melanoma remains unclear. miR-224–5p levels were downregulated in melanoma tissue, and low miR-224–5p expression was an independent risk factor for melanoma patients. miR-224–5p blocked proliferation, epithelial-to-mesenchymal transition (EMT), invasion, migration in BRAF wild-type melanoma cell, and overcome acquired BRAFi resistance in VMF-resistant melanoma cells. miR-224–5p exerted its role by directly repressing PAK4 to block the downstream CRAF/MEK/ERK pathways. We demonstrated that miR-224–5p inhibited melanoma growth and metastasis in vivo though xenograft tumor and pulmonary metastasis assay. Thus, miR-224–5p/PAK4-mediated CRAF/MEK/ERK pathways have therapeutic potential in melanoma treatment.

Zirconium oxychloride assessment by XPS

Zirconium oxychloride was characterized by x-ray photoelectron spectroscopy. The specimen is a powder purchased from Sigma Aldrich. The sample was fixed to a stainless-steel sample holder with copper 3MTM double-sided adhesive tape. Survey spectra, Zr 3d, O 1s, C 1s, Cl 2p, Zr 3p, Zr 4p, and Cl 2s core levels spectra were acquired. Results showed how the elements in the structure of zirconium oxychloride interact.

MiR-128–3p increases the radiosensitivity in nasopharyngeal carcinoma via regulating vascular endothelial growth factor C

PurposeThis study aims to investigate the role of miR-128–3p in the radiosensitivity of nasopharyngeal carcinoma (NPC) and its underlying mechanism. Methods6–10B cells were transfected with miR-128–3p mimic, pcDNA-VEGFC, and the corresponding negative control. C666–1 cells were transfected with miR-128–3p inhibitor, sh-VEGFC, and the corresponding negative control. RT-qPCR was used to determine the miR-128–3p and VEGFC mRNA expression level. Dual-luciferase assay was used to investigate the relationship between miR-128–3p and VEGFC. The protein levels of VEGFC, H2AX, γ-H2AX, p-P50, p-P65, p-IκB, and the apoptosis markers Bcl-2, caspase3, caspase9, and Bax were detected by Western blot. The proliferation activity was detected by CCK-8, and cell DNA damage was assessed by comet assay. The apoptosis rate was detected by flow cytometry. The growth of NPC in vivo was observed in mice through xenotransplantation. TUNEL staining was used to detect cell apoptosis in tumor tissues. ResultsmiR-128–3p was targeted and was negatively regulated with VEGFC. Overexpression of miR-128–3p or knockdown VEGFC significantly inhibited the proliferation of 6–10B and C666–1 cells, induced DNA damage and apoptosis and promoted the radiosensitivity of cells. Knocking down miR-128–3p or up-regulated VEGFC promoted the proliferation of C666–1 and 6–10B cells, reduced cell DNA damage and apoptosis, and enhanced cell resistance to radiotherapy. Overexpression of miR-128–3p reversed the effect of VEGFC on 6–10B cells and inhibited P50/P65/IKB signal pathway. In vivo, experiments in mice confirmed that miR-128–3p significantly inhibited NPC proliferation and promoted DNA damage and apoptosis by targeting VEGFC. ConclusionThe miR-128–3p pathway is a novel therapy target to overcome radiation resistance in NPC.

Investigating the potential of thiazolyl carbohydrazides derivatives as anti-Candida albicans agents: An intuition from molecular modelling, pharmacokinetic evaluation, and molecular docking analysis

With increasing incidences of antifungal resistance, biofilm formation, and its predilection for vulnerable populations, Candida albicans have been reported to cause a wide range of infections, from superficial skin irritations to life-threatening systemic diseases. Therefore, understanding and addressing the infections associated with Candida albicans has become an urgent imperative in the realm of global healthcare. As a result, this study employed DFT calculations at the DFT/ωB97XD/6–311++G (2d, 2p) level to optimize the geometric properties of two compounds: (Z)-N'-(4-(4-bromophenyl)-3-(4-fluorophenyl)thiazol-2(3H)-ylidene)-2-(thiophen-2-yl)thiazole-5-carbohydrazide (4-FBC) and (Z)-N'-(4-(4-bromophenyl)-3-(2-fluorophenyl)thiazol-2(3H)-ylidene)-2-(thiophen-2-yl)thiazole-5-carbohydrazide(2-FBC). Significantly, employing spectral analysis techniques such as FT-IR and NMR, the compounds were characterized and identified. Additionally, the compounds (4-FBC and 2-FBC) exhibited comparable reactivity and stability, with more promising reactivity potential in water than in the gas phase. The analysis of Molecular Electrostatic Potential (MESP) and the density of States (DOS) shed light on the electrical characteristics and intermolecular interactions occurring during chemical processes. Furthermore, the natural bond orbital (NBO) analysis provided insights into second-order perturbation energies and the presence of intense intermolecular interactions, as evident in the order of their increasing concentrated intermolecular interaction as thus: 4-FBC_gas (668.34 kcal/mol) > 4-FBC _water (563.98 kcal/mol) and 2-FBC _gas (978.64 Kcal/mol) > 2-FBC_water (696.46 Kcal/mol). The pharmacokinetics study indicated favorable intestinal absorption, low distribution, and cytotoxicity profiles, although 4-FBC required further optimization due to slower clearance, potential enzyme interactions, and immunotoxicity concerns. In addition, molecular docking analysis revealed robust binding affinities and the presence of significant conventional hydrogen bonds. The optimal binding positions (best pose) for the 4-FBC and 2-FBC complexes were determined to have binding affinities of -8.7, -8.4, -8.3 kcal/mol, and -8.6, -8.5, -8.3 kcal/mol, respectively, when interacting with 4YDE, 3DRA, and 1EAG. These findings provide strong evidence supporting the potential pharmacological suitability of 4-FBC and 2-FBC compounds as effective choices for inhibiting and treating Candida albicans.

Insights into in-vitro studies and molecular modelling of the antimicrobial efficiency of 4-chlorobenzaldehyde and 4-methoxybenzaldehyde derivatives

Owing to the significant gap in the knowledge and understanding of the mechanisms of antimicrobial action and the development of resistance, the optimization of antimicrobial therapies therefore becomes a necessity. It is on this note, that this study seeks to both experimentally and theoretically investigate the antimicrobial efficiency of two synthesized compounds namely; 1-((4-methoxyphenyl) (morpholino)methyl)thiourea (MR1) and diethyl 4-(4-chlorophenyl)-2,6-diphenyl-1,4-dihydropyridine-3,5-dicarboxylate (HRC). Utilizing the density functional theory (DFT), the compounds were optimized at ωB97XD/6-31++G(2d, 2p) level of theory. This provided a clear explanation for their distinct reactivity and stability potentials. More so, the natural bond orbital (NBO) analysis confirmed strong intra and intermolecular interactions, which agreed with the calculated reactivity parameters and density of states (DOS). Upon assessing the antimicrobial efficacy of the synthesized compounds, it was found that they exhibited lower activity against Enterobacter and A. niger, but considerable activity against Moraxella. In contrast, they showed higher activity against B. subtilis and Trichophyton, indicating that the compounds are more effective against gram-positive bacteria than gram-negative ones. Hence, it can be asserted that the synthesized compounds have superior antifungal action than antibacterial activity. A fascinating aspect of the data is that they show interactions that are incredibly insightful, totally correlating with the simulations of both molecular docking and molecular dynamics. Therefore, the alignment between experimental findings and computational simulations strengthens the validity of the study’s conclusions, emphasizing the significance of the synthesized compounds in the context of optimizing antimicrobial therapies. Communicated by Ramaswamy H. Sarma

MiRNA 511_5p is a potential biomarker for ocular toxoplasmosis.

Ocular toxoplasmosis (OT) is a frequent clinical manifestation due to infection by Toxoplasma gondii. It is characterized by an inflammatory process involving macrophages activated by pro-inflammatory cytokines. The expression of microRNAs takes place during the inflammatory process and, among them, miRNA 511 regulates the activation of macrophages. This study evaluated the expression of miRNA 511_5p in patients with OT and healthy controls. A total of 361 patients from the Hospital de Base of Fundação Faculdade de Medicina de São José do Rio Preto were enrolled and divided into four groups: G1-patients with active ocular lesions and reagent serology for T. gondii; G2-patients with scars and reagent serology for T. gondii; G3-patients without ocular lesions or scars and reagent serology for T. gondii; G4-patients without ocular lesions or scars and non-reagent serology for T. gondii. All patients underwent clinical and laboratory evaluation to confirm the diagnosis of OT. Serology tests, RNA extraction and cDNA synthesis were performed. The miRNA 511_5p levels were compared among the groups. The G1 group showed a high blood plasma concentration of miRNA 511_5p (mean 22.34) compared with the G2 (4.65), G3 (8.91) and G4 (3.52) groups (p<0.0001). These data suggest that miRNA 511_5p has significant potential as a biomarker for OT.

Spectroscopic characterization, polar solvation effects, DFT studies, and the antiviral inhibitory potency of a novel terpolymer based on p-Phenylenediamine – Guanidine – Formaldehyde (PGF) ligand

This study articulates the synthesis, spectroscopic characterization, solvation effects, theoretical calculations, and molecular docking analysis of a novel p-Phenylenediamine – Guanidine – Formaldehyde (PGF) terpolymer ligand as potential antiviral agents. The terpolymer's structure was established using FT-IR, UV-visible, 1H, and 13C NMR spectroscopy. Its thermal degradation was also examined using thermogravimetric analysis. Theoretical studies based on density functional theory (DFT) at the B3LYP-D3(BJ)/6-311G++G (2d, 2p) level of theory was utilized to investigate the influence of solvation (in DMSO, water, ethanol and methanol) on the structural, electronic, and spectroscopic properties of the studied polymer. Results of the visual studies suggest that the complexes displayed an enormously weaker interactions or Van der Walls interactions with sparsely strong hydrogen bonding, along with minimally strong steric interactions or repulsion. Therefore, it can be surmised that the iso-surface present in PG_DMSO_OPT, PG_ETHANOL_OPT, PG_METHANOL_OPT and PG_WATER_OPT are prominent for van der walls interactions with strong hydrogen bonding contacts which makes the complexes very promising for drug interactions and/or Protein-Ligand Interaction. Summarily, molecular docking analysis indicated that the PGF terpolymer ligand has potent inhibitory effects on HIV target receptors, particularly 3LAK HIV protein; due to the proteins’ high negative binding affinity, and greater number of conventional hydrogen bonds compared to 3LAN. Summarily, this study presents a new terpolymer ligand with potential biological applications, particularly in the development of HIV inhibitors.

Indium acetate analyzed by XPS

Indium acetate was analyzed using x-ray photoelectron spectroscopy. The specimen is a powder purchased from Sigma Aldrich. The sample was fixed to a stainless-steel sample holder with copper 3MTM double-sided adhesive tape. Survey spectra, In 3d, O 1s, C 1s, In 3p, In MNN, and Cl 2p core levels spectra were acquired. Results showed how the elements in the structure of indium acetate are related.

Human umbilical cord mesenchymal stem cell-derived extracellular vesicles improve ovarian function in rats with primary ovarian insufficiency by carrying miR-145–5p

ObjectiveStem cell/exosome therapy is a novel strategy for primary ovarian insufficiency (POI). This paper is to examine the role of human umbilical cord mesenchymal stem cell-derived extracellular vesicles (hUCMSC-EVs) in POI. MethodshUCMSC-EVs were extracted and identified. POI rats were induced by cyclophosphamide for 15 days and treated with EV or GW4869 every 5 days and euthanized 28 days later. Vaginal smears were observed for 21 days. Serum hormone levels (FSH/E2/AMH) were measured by ELISA. Ovarian morphology, follicle numbers, and granulosa cell (GC) apoptosis were observed by HE and TUNEL staining. GCs extracted from Swiss albino rats were cyclophosphamide-induced to establish the POI cell model, followed by oxidative injury and apoptosis evaluation with the help of DCF-DA fluorescence, ELISA, and flow cytometry. The relation between miR-145–5p and XBP1 was predicted on StarBase and validated by dual-luciferase assay. miR-145–5p and XBP1 levels were measured by RT-qPCR and Western blot. ResultsEV treatment reduced irregular estrus cycle incidence since day 7, increased E2 and AMH levels and all-stage follicle numbers, reduced FSH level, GC apoptosis, and atretic follicle numbers in POI rats. EV treatment diminished GC oxidative injury and apoptosis in vitro. miR-145–5p knockdown in hUCMSC-EVs partly abolished hUCMSC-EV-mediated effects on GCs and ovarian function in vivo and on GC oxidative injury and apoptosis in vitro. Silencing XBP1 partially negated miR-145–5p knockdown-exerted effects on GCs in vitro. ConclusionmiR-145–5p carried by hUCMSC-EVs attenuates GC oxidative injury and apoptosis and thus extenuates ovarian injury and improves ovarian function in POI rats.

Let-7a/cMyc/CCAT1/miR-17–5p Circuit Re-sensitizes Atezolizumab Resistance in Triple Negative Breast Cancer through Modulating PD-L1

BackgroundTriple negative breast cancer (TNBC) is an immunogenically hot tumor. The immune checkpoint blockades (ICBs) have been recently emerged as promising therapeutic candidates for several malignancies including TNBC. Yet, the development of innate and/or adaptive resistance by TNBC patients towards ICBs such as programmed death-ligand 1 (PD-L1) inhibitors (e.g. Atezolizumab) shed the light on importance of identifying the underlying mechanisms regulating PD-L1 in TNBC. Recently, it was reported that non-coding RNAs (ncRNAs) perform a fundamental role in regulating PD-L1 expression in TNBC. Hence, this study aims to explore a novel ncRNA axis tuning PD-L1 in TNBC patients and investigate its possible involvement in fighting Atezolizumab resistance. MethodsIn-silico screening was executed to identify ncRNAs that could potentially target PD-L1. Screening of PD-L1 and the nominated ncRNAs (miR-17–5p, let-7a and CCAT1 lncRNA) was performed in BC patients and cell lines. Ectopic expression and/or knockdown of respective ncRNAs were performed in MDA-MB-231. Cellular viability, migration and clonogenic capacities were evaluated using MTT, scratch assay and colony-forming assay, respectively. ResultsPD-L1 was upregulated in BC patients, especially in TNBC patients. PD-L1 is positively associated with lymph node metastasis and high Ki-67 in recruited BC patients. Let-7a and miR-17–5p were nominated as potential regulators of PD-L1. Ectopic expression of let-7a and miR-17–5p caused a noticeable reduction in PD-L1 levels in TNBC cells. In order to investigate the whole ceRNA circuit regulating PD-L1 in TNBC, intensive bioinformatic studies were performed. The lncRNA, Colon Cancer-associated transcript 1 (CCAT1), was reported to target PD-L1 regulating miRNAs. Results showed that CCAT1 is an upregulated oncogenic lncRNA in TNBC patients and cell lines. CCAT1 siRNAs induced a noticeable reduction in PD-L1 levels and a marked increase in miR-17–5p level, building up a novel regulatory axis CCAT1/miR-17–5p/PD-L1 in TNBC cells that was tuned by the let-7a/c-Myc engine. On the functional level, co-treatment of CCAT-1 siRNAs and let-7a mimics efficiently relieved Atezolizumab resistance in MDA-MB-231 cells. ConclusionThe present study revealed a novel PD-L1 regulatory axis via targeting let-7a/c-Myc/CCAT/miR-17–5p. Additionally, it sheds the light on the potential combinational role of CCAT-1 siRNAs and Let-7a mimics in relieving Atezolizumab resistance in TNBC patients.