Search Results (476)

L-type Ca²⁺ channels, particularly Ca_V1.2, play a crucial role in cardiac excitation-contraction coupling and are known to exhibit mechanosensitivity. However, the mechanisms regulating their response to mechanical stress remain poorly understood. To investigate the mechanosensitivity and nitric oxide (NO)-dependent regulation of L-type Ca²⁺ channels in rat ventricular cardiomyocytes, we used RNA sequencing to assess isoform expression and whole-cell patch-clamp recordings to measure L-type Ca²⁺ current (I_Ca,L) under controlled mechanical and pharmacological conditions. RNA sequencing revealed predominant expression of Ca_V1.2 (TPM: 0.1170 ± 0.0075) compared to Ca_V1.3 (0.0021 ± 0.0002) and Ca_V1.1 (0.0002 ± 0.0002). Local axial stretch (6–10 μm) consistently reduced I_Ca,L in proportion to stretch magnitude. The NO donor SNAP (200 μM) had variable effects on basal I_Ca,L in unstretched cells (stimulatory, inhibitory, or biphasic) but consistently restored stretch-reduced I_Ca,L to control levels. Ascorbic acid (10 μM), which reduces S-nitrosylation, increased basal I_Ca,L and partially restored the reduction caused by stretch, implicating S-nitrosylation in channel regulation. The sGC inhibitor ODQ (5 μM) decreased I_Ca,L in both stretched and unstretched cells, indicating involvement of the NO–cGMP pathway. Mechanical stress modulates L-type Ca²⁺ channels through a complex interplay between S-nitrosylation and NO–cGMP signaling, with S-nitrosylation playing a predominant role in stretch-induced effects. This mechanism may represent a key component of cardiac mechanotransduction and could be relevant for therapeutic targeting in cardiac pathologies involving mechanically induced dysfunction. Full article

Cardiomyocytes, similarly to cells in various tissues, are responsive to mechanical stress of all types, which is reflected in the significant alterations to their electrophysiological characteristics. This phenomenon, known as mechanoelectric feedback, is based on the work of mechanically gated channels (MGCs) and mechano-sensitive channels (MSCs). Since microgravity (MG) in space, as well as simulated microgravity (SMG), changes the morphological and physiological properties of the heart, it was assumed that this result would be associated with a change in the expression of genes encoding MGCs and MSCs, leading to a change in the synthesis of channel proteins and, ultimately, a change in channel currents during cell stretching. In isolated ventricular cardiomyocytes of rats exposed to SMG for 14 days, the amount of MGCs and MSCs gene transcripts was studied using the RNA sequencing method by normalizing the amount of “raw” reads using the Transcripts Per Kilobase Million (TPM) method. Changes in the level of channel protein, using the example of the MGCs TRPM7, were assessed by the Western blot method, and changes in membrane ion currents in the control and during cardiomyocyte stretching were assessed by the patch-clamp method in the whole-cell configuration. The data obtained demonstrate that SMG results in a multidirectional change in the expression of genes encoding various MGCs and MSCs. At the same time, a decrease in the TPM of the MGCs TRPM7 gene leads to a decrease in the amount of TRPM7 protein. The resulting redistribution in the synthesis of most channel proteins leads to a marked decrease in the sensitivity of the current through MGCs to cell stretching and, ultimately, to a change in the functioning of the heart. Full article

Niacinamide was recently shown to directly interact with bacterial DNA and interfere with cell replication; niacinamide mode of interaction and efficacy as a natural anti-microbial molecule were also described. The aim of this study is to elucidate the exact binding mechanism of niacinamide to microbial DNA. Intercalation is a binding mode where a small planar molecule, such as niacinamide, is inserted between base pairs, causing structural changes in the DNA. Melting curve analysis with various intercalating dyes demonstrated that niacinamide interaction with bacterial DNA reduces its melting temperature in a linear dose-dependent manner. Niacinamide’s effect on the melting temperature was found to be % GC-dependent, while purine stretches were also found to influence the binding kinetics. Finally, fluorescent intercalator displacement (FID) assays demonstrated that niacinamide strongly reduces SYBR Safe signal in a dose-dependent manner. Interestingly, competition assays with a minor groove binder also reduced Hoechst signal but in a non-linear manner, which can be attributed to strand lengthening and unwinding following niacinamide intercalation. Taken altogether; our results suggest a “disruptive intercalation” as the mode of interaction of niacinamide with bacterial DNA. Formation of locally destabilized DNA portions by niacinamide might interfere with protein–DNA interaction and potentially affect several crucial bacterial cellular processes, e.g., DNA repair and replication, subsequently leading to cell death. Full article

The mechanical properties of cell scaffolds are strongly influenced by their hydration state. In this study, we investigated the effect of the aqueous phase on the elastic modulus of chitosan hydrogel films using two complementary techniques: uniaxial tensile testing and atomic force microscopy (AFM) nanoindentation. Our results demonstrate that hydration markedly reduced the elastic modulus, decreasing from approximately 2 GPa in dry films to 120 kPa in swollen films, primarily due to the plasticizing effect of water. Moreover, hydrogel films in equilibrium with the aqueous phase exhibited a Young’s modulus three times lower than that of swollen films not in equilibrium. Raman spectroscopy further reveals a solvent “squeeze-out” phenomenon, as evidenced by an increased signal intensity in the 850–1200 cm⁻¹ region for stretched films that were out of swelling equilibrium, whereas equilibrated films showed stable spectral features. These findings highlight the crucial role of hydration dynamics in determining the mechanical behavior of chitosan hydrogel films, offering valuable insights for tailoring their properties in biomedical scaffold applications. Full article

Background/Objectives: Carbohydrate antigen 125 (CA125) is a glycoprotein commonly overexpressed in epithelial ovarian cancer and widely recognized as a tumor marker. However, elevated CA125 levels are also observed in various non-malignant conditions, including diseases affecting mucosal surfaces, pleural or peritoneal effusions, cirrhosis (with or without ascites), endometriosis, uterine fibroids, adenomyosis, pelvic inflammatory disease, and pregnancy. This review aims to explore the role of CA125 in non-malignant serous effusions, highlighting its diagnostic and prognostic potential beyond the realm of oncology. Methods: A comprehensive literature search was conducted across multiple databases and clinical trial registries. Eligible studies included full-text original research articles, reviews, and case reports published in English over the past 10 years. Inclusion criteria were limited to studies involving human subjects and focused on the role of CA125 in non-malignant serous effusions. Results: CA125 is produced by coelomic epithelial cells lining the ovary, pleura, pericardium, and peritoneum. Its serum concentration is not significantly influenced by age, body weight, or renal function, even in the advanced stages of the disease. In peritoneal conditions, CA125 is synthesized by mesothelial cells and serves as a potential marker of peritoneal involvement. The prevailing pathophysiological mechanism suggests that mechanical stretching of mesothelial cells due to ascitic pressure stimulates CA125 release. Similarly, in heart failure, mesothelial cells of the pericardium produce CA125, which correlates with congestion severity, supports risk stratification, and may inform diuretic therapy. Conclusions: While a threshold of 35 U/mL is established for malignancy, no standardized cutoff exists for CA125 in non-malignant conditions. The utility of CA125 measurement in peritoneal, pleural, or pericardial effusions—and cardiovascular diseases such as acute heart failure—for purposes of differential diagnosis, treatment guidance, or prognostication warrants further investigation through prospective clinical trials. Full article

Significant heavy metals contamination is often caused by rapid industrialization, which is devastating to both public health and the environment. Conventional processes of metal removal also result in the accumulation of secondary waste. This work proposes the use of a novel fungal biomass (microwave heat dried) from Arthrinium malaysianum for the biosorption of toxic chromium. We have meticulously explored and investigated the interactions of hexavalent chromium with dried biomass using several cutting-edge techniques like FTIR for studying the involvement of functional groups on the biomass surface, XRD for the surface architecture changes after metal binding, XPS to unravel the reduction of hexavalent chromium into its non-toxic form, and FESEM-EDX for the visualization of the ultra-structure of fungal cell surface. The Langmuir isotherm demonstrates that the maximum removal capacity Q_max of Cr(VI) is 102.310 mgg⁻¹, at a pH of 3.5 with 100% removal of Cr(VI). There were substantial changes in the surface architecture during adsorption, confirmed by FESEM and AFM studies. FTIR and XPS data analysis indicated that carbonyl, hydroxyl, phosphate, and amine groups were responsible for the conversion of Cr(VI) (toxic) to Cr(III) (non-toxic). The IR spectra of biomass treated with Cr showed a decreased C-O stretching intensity and slight shriveling of the -OH band, and the bands in the FTIR spectra at 1642 cm⁻¹ to 1635 cm⁻¹ and at 1549 cm⁻¹ to 1547 cm⁻¹ shifted and appeared quite distinct. XRD revealed that the chromium-treated biomass had greater crystalline features and also the appearance of a wide peak where 2θ = 20°, approximately, indicating an amorphous nature at 576.0 eV and in highly loaded chromium (500 mg/L) biomass, with the Cr2p level displaying a slight shift, eventually terminating in a (576.0 eV) Cr₂O₃ to Cr(III) peak. Since the FTIR and XPS data obtained revealed that Cr(VI) reduces to Cr(III), this fungal biomass can also be used for generating metallic nanoparticles during biosorption. Thus, we suggest that the above-mentioned fungal biomass could be a very useful biomaterial for future translational research. We are in the process of fabricating beads with powdered biomass for further studies. Full article

Cyclic mechanical stretch has been shown to inhibit myoblast differentiation while promoting proliferation. However, the underlying molecular mechanisms are not well understood. Here, we report that mechanical stretch inhibits the differentiation of mouse primary myoblasts by promoting the cell cycle program and by inhibiting the expression of the myogenic regulator MyoD. Stretch alters the miRNA expression profile as evidenced by miRNA microarray analysis. We identified miR-200c as one of the highly downregulated mechanosensitive miRNAs (mechanomiRs) whose expression level was increased during differentiation. This suggests that mechanomiRs-200c is a myogenic miRNA. Overexpression of mechanomiR-200c revoked the effect of stretch on myoblast differentiation, and the introduction of the mechanomiR-200c antagomir restored the stretch effect. This suggests that stretch blocks differentiation, in part, through mechanomiR-200c. The gene encoding the transcription factor FoxO3 is a known direct target of mechanomiR-200c. Interestingly, MyoD binds to the mechanomiR-200c promoter in differentiating myoblasts, whereas stretch appears to reverse such binding. Our data further demonstrate that the levels of mechanomiR-200c are robustly elevated during the early stage of the muscle repair process in young mice, but not in the injured muscle of aged mice. Overall, we identified a novel pathway, MyoD/mechanomiR-200c/FoxO3a, and the potential mechanism by which stretch inhibits myoblast differentiation. Full article

Heart failure (HF) remains a major global health challenge, driven by multifactorial pathophysiological processes, such as systemic congestion, endothelial dysfunction, and inflammation. While natriuretic peptides are well-established biomarkers for diagnosing and monitoring HF, they do not fully capture the complexity of vascular involvement. CD146, also known as melanoma cell adhesion molecule (MCAM), is a transmembrane glycoprotein primarily expressed on endothelial cells and involved in cell adhesion, vascular permeability, and angiogenesis. Its soluble form (sCD146), released in response to multiple pathophysiological stimuli, including venous and arterial endothelial stretch, oxidative stress, and inflammatory cytokine activation, has emerged as a promising biomarker reflecting both hemodynamic congestion and systemic endothelial stress. This review synthesizes current knowledge on the structure, regulation, and release mechanisms of CD146 and explores its clinical utility in HF. Elevated sCD146 levels have been associated with echocardiographic and radiological indicators of congestion, as well as with adverse outcomes. While promising, its application is limited by variability, lack of standardization, and confounding elevations in non-cardiac conditions, including malignancy. Full article

Dipalmitoylphosphatidylcholine (DPPC), is one of the key bilayer membranes of the phosphatidylcholine (PC) family which constitutes 40–50% of total cellular phospholipids in mammal cells. We investigate the behavior of an initially planar DPPC membrane under lateral pressures from −200 to 150 bar at 323 K using microsecond-scale simulations. We identify, with very high precision, the pressure range for the occurrence of critical phenomena, mainly undulation and rupture. Notably, under compression, the membrane initially thickens, leading to a phase transition to an undulated state between 40 and 50 bar, as gauged by the sharp changes in the diverse structural metrics. Stretching induces systematic membrane thinning, with rupture becoming probable at −170 bar and certain at −200 bar. The reverse compression cycle shows pressure hysteresis with a 10-bar shift, while the reverse stretching cycle retraces the pathway. System size has a minimal impact on the observed trends. Under extreme mechanical stress, particularly near critical phenomena, simulation times on the order of microsecond are needed to accurately capture phase behavior and structural alterations. This work provides important insights into understanding membrane behavior under extreme conditions, which are relevant to numerous biological and technological applications. Full article

Most high-order Euler-type methods have been proposed to solve one-dimensional scalar hyperbolic conservational law. These methods resolve smooth variations in flow parameters accurately and simultaneously identify the discontinuities. A disadvantage of Euler-type methods is the parameter change stretching in the shock over a few mesh cells. In reality, in the shock, the flow properties change abruptly at once for the computational mesh. In our considerations, the mean free path of a flow particle is much smaller than the mesh cell size. This paper describes a modification of the semi-Lagrangian Godunov-type method, which was proposed by the author in the previously published paper. The modified method also does not have numerical viscosity for shocks. In the previous article, a linear law for the distribution of flow parameters was employed for a rarefaction wave when modeling the Shu-Osher problem with the aim of reducing parasitic oscillations. Additionally, the nonlinear law derived from the Riemann invariants was used for the remaining test problems. This article proposes an advanced method, namely, a unified formula for the density distribution of rarefaction waves and modification of the scheme for modeling moderately strong shock waves. The obtained results of numerical analysis, including the standard problem of Sod, the Riemann problem of Lax, the Shu–Osher shock-tube problem and a few author’s test cases are compared with the exact solution, the data of the previous method and the Total Variation Deminishing (TVD) scheme results. This article delineates the further advancement of the numerical scheme of the proposed method, specifically presenting a unified mathematical formulation for an expanded set of test problems. Full article

Background: Studies on somatic mutations in cancer typically report single-nucleotide variants in coding regions, while mutations in short tandem repeats (STRs) are usually overlooked. Homopolymeric regions, a subset of STRs, are stretches of DNA where only a single nucleotide is repeated multiple times (e.g., AAAAA or TTTTT). Only recently have mutations in such STR regions been seen in colorectal cancer, where microsatellite instability (MSI) is common. In non-melanoma skin cancer (NMSC), MSI is rare. In this study, we focus on somatic mutations in such homopolymeric regions in NMSC and their functional implications. Methods: We performed targeted DNA sequencing (paired tissue and blood from the same individual), using more than 400 cancer-related genes from 32 NMSC patients as cases and non-lesional skin tissue from 16 independent individuals as controls. Results: We identified NMSC-associated STR somatic mutations. These are associated with the dysregulation of DNA damage and repair mechanisms. In artificial intelligence (AI) predictive modeling, these markers could successfully differentiate basal cell carcinoma (BCC) and non-lesional skin tissue. To our knowledge, we present the first study focusing on STR somatic mutations in multiple cancer-related genes in NMSC found only in tumor tissue and not in non-lesional skin tissue. Some of them (APC, BRAF) are associated with more pronounced dysregulation of relevant gene pathways (hedgehog, Notch signaling, and Wnt signaling). Conclusions: Our findings suggest that this STR somatic mutation status might potentially be used to select BCC patients who could benefit from certain precision therapy including hedgehog inhibitors, gamma-secretase inhibitors, anti-Vasuclar endothelial growth factor (VEGF), proteasome inhibitors, and immune check-point inhibitors. Full article

Raman spectroscopy is one of the best techniques for obtaining information concerning the physical–chemical interactions between a lipid and a solvent. Phospholipids in water are the main elements of cell membranes and, by means of their chemical and physical structures, their cells can interact with other biological molecules (i.e., proteins and vitamins) and express their own biological functions. Phospholipids, due to their amphiphilic structure, form biomimetic membranes which are useful for studying cellular interactions and drug delivery. Synthetic systems such as DPhPC-based liposomes replicate the key properties of biological membranes. Among the different models, phospholipid mimetic membrane models of lamellar vesicles have been greatly supported. In this work, a biomimetic system, a deuterium solution (50 mM) of the synthetic phospholipid 1,2-diphytanoyl-sn-glycero-3-phosphocholine (DPhDC), is studied using μ-Raman spectroscopy in a wide temperature range from −181.15 °C up to 22.15 °C, including the following temperatures: −181.15 °C, −146.15 °C, −111.15 °C, −76.15 °C, −61.15 °C, −46.15 °C, −31.15 °C, −16.15 °C, −1.15 °C, 14.15 °C, and 22.15 °C. Based on the Raman evidence, phase transitions as a function of temperature are shown and grouped into five classes, where the corresponding Raman modes describe the stretching of the (C−N) bond in the choline head group (gauche) and the asymmetric stretching of the (O−P−O) bond. The acquisition temperature of each Raman spectrum characterizes the rocking mode of the methylene of the acyl chain. These findings enhance our understanding of the role of artificial biomimetic lipids in complex phospholipid membranes and provide valuable insights for optimizing their use in biosensing applications. Although the phase stability of DPhPC is known, the collected Raman data suggest subtle molecular rearrangements, possibly due to hydration and second-order transitions, which are relevant for membrane modeling and biosensing applications. Full article

Background/Objectives: Nanocarrier particle design for treating chronic pulmonary diseases presents several challenges, including anatomical and physiological barriers. Drug-repurposing technology using monodispersed spherical silica is one of the innovative ways to deliver drugs. In the present study, the anticancer potential of combinational cisplatin/ribavirin was explored for targeted lung cancer therapeutics. Methods: Monodispersed spherical silica (80 nm) capable of diffusing into the tracheal mucus region was chosen and doped with 10 wt% superparamagnetic iron oxide nanoparticles (SPIONs). Subsequently, it was wrapped with chitosan (Chi, 0.6 wt/vol%), functionalized with 5% wt/wt cisplatin (Cp)/ribavarin (Rib) and angiotensin-converting enzyme 2 (ACE-2) (1.0 μL/mL). Formulations are based on monodispersed spherical silica or halloysite and are termed as (S/MSSiO₂/Chi/Cp/Rib) or (S/Hal/Chi/Cp/Rib), respectively. Results: X-ray diffraction (XRD) and diffuse reflectance UV-visible spectroscopy (DRS-UV-vis) analysis of S/MSSiO₂/Chi/Cp/Rib confirmed the presence of SPION nanoclusters on the silica surface (45% coverage). The wrapping of chitosan on the silica was confirmed with a Fourier transformed infrared (FTIR) stretching band at 670 cm⁻¹ and ascribed to the amide group of the polymer. The surface charge by zetasizer and saturation magnetization by vibrating sample magnetometer (VSM) were found to be −15.3 mV and 8.4 emu/g. The dialysis membrane technique was used to study the Cp and Rib release between the tumor microenvironment and normal pH ranges from 5.5 to 7.4. S/MSSiO₂/Chi formulation demonstrated pH-responsive Cp and Rib at acidic pH (5.6) and normal pH (7.4). Cp and Rib showed release of ~27% and ~17% at pH 5.6, which decreases to ~14% and ~3.2% at pH 7.4, respectively. To assess the compatibility and cytotoxic effect of our nanocomposites, the cell viability assay (MTT) was conducted on cancer lung cells A549 and normal HEK293 cells. Conclusions: The study shows that the designed nanoformulations with multifunctional capabilities are able to diffuse into the lung cells bound with dual drugs and the ACE-2 receptor. Full article

In this study, a vanadyl phthalocyanine was synthesized and characterized using XRD, FTIR, and XPS, confirming the successful metalation of the phthalocyanine ring. XRD analysis showed the vanadyl phthalocyanine crystallized in the P-1 crystal lattice, with unit cell parameters a = 12.058 Å, b = 12.598 Å, and c = 8.719 Å, and the lattice angels were 96.203°, 94.941°, and 68.204°. FTIR spectroscopy supported the metalation by the disappearance of the N-H stretch of the non-metalated phthalocyanine. The vanadyl phthalocyanine was tested as a heterogenous catalyst for the conversion of fructose into methyl levulinate in H₂SO₄–methanol and HCl–methanol systems. The H₂SO₄–methanol reaction system catalyzed with the vanadyl phthalocyanine, and a zeroth-order rate constant of 1.10 × 10⁻⁶ M/s was observed, which was 1.74 times faster than sulfuric acid alone. The HCl–methanol system showed a zeroth-order of reaction with a rate constant of 2.33 × 10⁻⁶ M/s, which was 1.3 times faster than the HCl–methanol alone. While the HCl–methanol system showed a faster reaction rate, product distribution favored methyl levulinate formation in the H₂SO₄–methanol system. The main products identified were methyl levulinate and hepta-2,4-dienoic acid methyl ester, with a minor amount of hydroxymethylfurfural formed. These results suggest that vanadyl phthalocyanine can be effectively used as a catalyst to increase the rate of fructose conversion to methyl levulinate in either H₂SO₄ or HCl–methanol. Full article

Background/Objectives: Fibroblast activation protein (FAP) has gained tremendous traction as a target for tumor imaging and cancer treatment, while also playing a key role in fibrosis. Our study aimed to evaluate [⁶⁸Ga]Ga-DATA^5m.SA.FAPi for PET imaging of replacement fibrosis following myocardial infarction (MI) or interstitial fibrosis associated with hypertrophy. Methods: MI or transverse aortic constriction (TAC)-induced hypertrophy was induced in C57BL/6 mice, with sham-operated animals serving as controls. At multiple time points during disease progression (1, 2, and 6 weeks post-surgery), [⁶⁸Ga]Ga-DATA^5m.SA.FAPi PET/CT scans were performed, followed by ex vivo investigations. Additionally, in vitro cell uptake experiments simulating hypertrophy were conducted. Results: Cardiac uptake of [⁶⁸Ga]Ga-DATA5m.SA.FAPi significantly increased two weeks after MI induction (MI: 2.1 ± 0.2%ID/g, n = 7 vs. SHAM: 1.1 ± 0.2%ID/g, n = 5; p = 0.002), confirmed by ex vivo autoradiography. No significant difference was observed at six weeks post-MI (MI: 1.1 ± 0.1%ID/g, n = 4 vs. SHAM: 0.8 ± 0.0%ID/g, n = 3), indicating infarct healing completion. In contrast, TAC mice showed increased uptake after six weeks (TAC: 1.8 ± 0.2%ID/g, n = 6; p = 0.007), related to interstitial fibrosis progression. Consistently, high-stretched cardiac fibroblasts demonstrated a higher uptake compared to low-stretched conditioned ones, suggesting the stretch mediates regulation of FAP. Conclusions: This study demonstrated the efficacy of [⁶⁸Ga]Ga-DATA^5m.SA.FAPi for longitudinal imaging of cardiac fibrosis in response to different cardiac injuries. In vivo FAP imaging during cardiac remodeling may serve as a valuable tool for diagnosing and predicting disease progression, ultimately aiding in the clinical management of patients. Full article