Surface modification of a commercial bone plate (Ti6Al4V) implant for improved antibacterial and cytocompatibility via thermal dewetting of a silver thin film.

The high demand for bone grafts has motivated the development of implants with excellent osteogenic activity, whereas the risk of implant-associated infection, particularly given the rise of antimicrobial resistance, has compelled the development of implants with innovative antimicrobial strategies in which a small amount of bactericidal agent can effectively kill a wide range of bacteria. To induce antibacterial property, the surface of Grade-5 bone plate titanium implants used in clinical applications was modified using direct current (DC) sputter coating followed by thermal annealing. The 15 nm silver film-coated implants were thermally annealed in the furnace for 15 min at 750 °C. The modified implant surface's antibacterial efficacy againstEscherichia coli(E. coli),Staphylococcus aureus(S. aureus),Salmonella typhi, andMethicillin-resistant staphylococcus aureusbacteria has been assessed using a colony-forming assay. On the modified implant surface, the growth ofE. coliandS. aureusbacteria is reduced by 99.72%, while highly drug-resistant bacteria are inhibited by 96.59%. The MTT assay was used to assess the cytotoxicity of the modified bone-implant surface against NIH3T3 mouse fibroblast cells. The modified bone-implant surface promoted fibroblast growth and demonstrated good cytocompatibility. Furthermore, the mechanical properties of the implant were not harmed by this novel surface modification method. This method is simple and provides new insight into surface modification of commercial metallic implants to have effective antibacterial properties against various classes of bacteria.

Multifunctional 58S Bioactive Glass/Silver/Cerium Oxide-Based Biocomposites with Effective Antibacterial, Cytocompatibility, and Mechanical Properties.

58S bioactive glass (BG) has effective biocompatibility and bioresorbable properties for bone tissue engineering; however, it has limitations regarding antibacterial, antioxidant, and mechanical properties. Therefore, we have developed BGAC biocomposites by reinforcing 58S BG with silver and ceria nanoparticles, which showed effective bactericidal properties by forming inhibited zones of 2.13 mm (against Escherichia coli) and 1.96 mm (against Staphylococcus aureus; evidenced by disc diffusion assay) and an increment in the antioxidant properties by 39.9%. Moreover, the elastic modulus, hardness, and fracture toughness were observed to be increased by ∼84.7% (∼51.9 GPa), ∼54.5% (∼3.4 GPa), and ∼160% (∼1.3 MPam1/2), whereas the specific wear rate was decreased by ∼55.2% (∼1.9 × 10-11 m3/Nm). X-ray diffraction, high-resolution transmission electron microscopy, and field emission scanning electron microscopy confirmed the fabrication of biocomposites and the uniform distribution of the nanomaterials in the BG matrix. The addition of silver nanoparticles in the 58S BG matrix (in BGA) increased mechanical properties by composite strengthening and bactericidal properties by damaging the cytoplasmic membrane of bacterial cells. The addition of nanoceria in 58S BG (BGC) increased the antioxidant properties by 44.5% (as evidenced by the 2,2-diphenyl-1-picrylhydrazyl assay). The resazurin reduction assay and MTT assay confirmed the effective cytocompatibility for BGAC biocomposites against mouse embryonic fibroblast cells (NIH3T3) and mouse bone marrow stromal cells. Overall, BGAC resulted in mechanical properties comparable to those of cancellous bone, and its effective antibacterial and cytocompatibility properties make it a good candidate for bone healing.

Polymer-lipid hybrid nanomedicines to deliver siRNA in and against glioblastoma cells.

Small interfering RNA (siRNA) holds great potential to treat many difficult-to-treat diseases, but its delivery remains the central challenge. This study aimed at investigating the suitability of polymer-lipid hybrid nanomedicines (HNMeds) as novel siRNA delivery platforms for locoregional therapy of glioblastoma. Two HNMed formulations were developed from poly(lactic-co-glycolic acid) polymer and a cationic lipid: 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP) or 3ß-[N-(N',N'-dimethylaminoethane)-carbamoyl]cholesterol (DC-Chol). After characterization of the HNMeds, a model siRNA was complexed onto their surface to form HNMed/siRNA complexes. The physicochemical properties and siRNA binding ability of complexes were assessed over a range of nitrogen-to-phosphate (N/P) ratios to optimize the formulations. At the optimal N/P ratio of 10, complexes effectively bound siRNA and improved its protection from enzymatic degradation. Using the NIH3T3 mouse fibroblast cell line, DOTAP-based HNMeds were shown to possess higher cytocompatibility in vitro over the DC-Chol-based ones. As proof-of-concept, uptake and bioefficacy of formulations were also assessed in vitro on U87MG human glioblastoma cell line expressing luciferase gene. Complexes were able to deliver anti-luciferase siRNA and induce a remarkable suppression of gene expression. Noteworthy, the effect of DOTAP-based formulation was not only about three-times higher than DC-Chol-based one, but also comparable to lipofectamine model transfection reagent. These findings set the basis to exploit this nanosystem for silencing relevant GB-related genes in further in vitro and in vivo studies.

Dihydroartemisinin eliminates senescent cells by promoting autophagy-dependent ferroptosis via AMPK/mTOR signaling pathway.

Cellular senescence is an irreversible cell-cycle arrest in response to a variety of cellular stresses, which contribute to the pathogenesis of a variety of age-related degenerative diseases. However, effective antisenescence strategies are still lacking. Drugs that selectively target senescent cells represent an intriguing therapeutic strategy to delay aging and age-related diseases. Thus, we thought to investigate the effects of dihydroartemisinin (DHA) on senescent cells and elucidated its mechanisms underlying aging. Stress-induced premature senescence (SIPS) model was built in NIH3T3 cells using H2O2 and evaluated by ß-galactosidase staining. Cells were exposed to DHA and subjected to cellular activity assays including viability, ferroptosis, and autophagy. The number of microtubule-associated protein light-chain 3 puncta was detected by immunofluorescence staining. The iron content was assessed by spectrophotometer and intracellular reactive oxygen species (ROS) was measured by fluorescent probe dichlorodihydrofluorescein diacetate. We found that DHA triggered senescent cell death via ferroptosis. DHA accelerated ferritin degradation via promoting autophagy, increasing the iron contents, promoting ROS accumulation, thus leading to ferroptotic cell death in SIPS cells. In addition, autophagy inhibitor BafA1 preconditioning inhibited ferroptosis induced by DHA. Moreover, Atg5 silencing and autophagy inhibitor BafA1 preconditioning inhibited ferroptosis induced by DHA. We also revealed that the expression of p-AMP-activated protein kinase (AMPK) and p-mammalian target of rapamycin (mTOR) in senescent cells was downregulated. These results suggested that DHA may be a promising drug candidate for clearing senescent cells by inducing autophagy-dependent ferroptosis via AMPK/mTOR signaling pathway.

Monitoring Circadian Oscillations with a Bioluminescence Reporter in Organoids.

Most living organisms possess circadian rhythms, which are biological processes that occur within a period of approximately 24 h and regulate a diverse repertoire of cellular and physiological processes ranging from sleep-wake cycles to metabolism. This clock mechanism entrains the organism based on environmental changes and coordinates the temporal regulation of molecular and physiological events. Previously, it was demonstrated that autonomous circadian rhythms are maintained even at the single-cell level using cell lines such as NIH3T3 fibroblasts, which were instrumental in uncovering the mechanisms of circadian rhythms. However, these cell lines are homogeneous cultures lacking multicellularity and robust intercellular communications. In the past decade, extensive work has been performed on the development, characterization, and application of 3D organoids, which are in vitro multicellular systems that resemble in vivo morphological structures and functions. This paper describes a protocol for detecting circadian rhythms using a bioluminescent reporter in human intestinal enteroids, which enables the investigation of circadian rhythms in multicellular systems in vitro.

Hydrogels Containing Chitosan-Modified Gold Nanoparticles Show Significant Efficacy in Healing Diabetic Wounds Infected with Antibiotic-Resistant Bacteria.

Purpose: Persistent Infections and inflammation are associated with impaired wound healing in diabetic patients. There is a pressing demand for innovative antimicrobial strategies to address infections arising from antibiotic-resistant bacteria. Polymer-modified gold nanoparticles (AuNPs) show broad-spectrum antibacterial properties and significant biocompatibility. This study investigated the antibacterial and wound healing efficacy of hydrogel dressings conjugated with chitosan-AuNPs in diabetic model rats. Methods: Chitosan (CS)-functionalized gold nanoparticles (CS-AuNPs) were incorporated into hydrogel dressings (Gel/CS-AuNPs), which were formulated through the chemical cross-linking of gelatin with sodium alginate (SA). The basic characteristics of Gel/CS-AuNPs were analyzed by TEM, SEM, XRD, and UV-visible spectra. Rheological, swelling, degradation, and adhesive properties of Gel/CS-AuNPs were also determined. In vitro anti-bactericidal effects of the Gel/CS-AuNPs were analyzed with E. coli, S. aureus, and MRSA. In vitro biocompatibility of the Gel/CS-AuNPs was evaluated using NIH3T3 cells. The in vivo antibacterial and wound healing efficacy of the Gel/CS-AuNPs was analyzed in the diabetic wound model rats. Histological and immunofluorescence staining were performed to determine the status of angiogenesis, epithelization, inflammation response, and collagen deposition. Results: Gel/CS-AuNPs demonstrated significant high biodegradability, water absorption bactericidal, and biocompatibility, and slight adhesiveness. Gel/CS-AuNPs exhibited pronounced antibacterial efficacy against gram-negative, gram-positive, and MRSA in a CS-AuNPs-dose-dependent manner. In the diabetic wound model rats, Gel/CS-AuNPs effectively killed MRSA, reduced inflammation, and promoted angiogenesis and collagen deposition and remodeling at the wound site. As a result, Gel/CS-AuNPs expedited the recovery process for infected diabetic wounds. Among the hydrogels with different CS-AuNPs concentrations, Gel/CS-Au25 with 25% CS-AuNPs showed the best bactericidal and wound healing performance. Conclusion: Gel/CS-AuNPs significantly improve the healing of MRSA-infected diabetic wounds in the rat model. Therefore, Gel/CS-AuNPs show great promise for the treatment of diabetic infection wound healing.

Antimicrobial Potency of Fmoc-Phe-Phe Dipeptide Hydrogels with Encapsulated Porphyrin Chromophores Is a Promising Alternative in Antimicrobial Resistance.

Antimicrobial resistance (AMR) poses a significant global health risk as a consequence of misuse of antibiotics. Owing to the increasing antimicrobial resistance, it became imperative to develop novel molecules and materials with antimicrobial properties. Porphyrins and metalloporphyrins are compounds which present antimicrobial properties especially after irradiation. As a consequence, porphyrinoids have recently been utilized as antimicrobial agents in antimicrobial photodynamic inactivation in bacteria and other microorganisms. Herein, we report the encapsulation of porphyrins into peptide hydrogels which serve as delivery vehicles. We selected the self-assembling Fmoc-Phe-Phe dipeptide, a potent gelator, as a scaffold due to its previously reported biocompatibility and three different water-soluble porphyrins as photosensitizers. We evaluated the structural, mechanical and in vitro degradation properties of these hydrogels, their interaction with NIH3T3 mouse skin fibroblasts, and we assessed their antimicrobial efficacy against Gram-positive Staphylococcus aureus (S. aureus) and Gram-negative Escherichia coli (E. coli) bacteria. We found out that the hydrogels are cytocompatible and display antimicrobial efficiency against both strains with the zinc porphyrins being more efficient. Therefore, these hydrogels present a promising alternative for combating bacterial infections in the face of growing AMR concerns.

The anti-neoplastic effects of metformin modulate the acquired phenotype of fibroblast cells in the breast cancer-normal fibroblast co-culture system.

Intracellular communications between breast cancer and fibroblast cells were reported to be involved in cancer proliferation, growth, and therapy resistance. The hallmarks of cancer-fibroblast interactions, consisting of caveolin 1 (Cav1) and mono-carboxylate transporter 4 (MCT4) (metabolic coupling markers), along with IL-6, TGFß, and lactate secretion, are considered robust biomarkers predicting recurrence and metastasis. In order to promote a novel phenotype in normal fibroblasts, we predicted that breast cancer cells could be able to cause loss of Cav1 and increase of MCT4, as well as elevate IL-6 and TGFß in nearby normal fibroblasts. We created a co-culture model using breast cancer (4T1) and normal fibroblast (NIH3T3) cell lines cultured under specific experimental conditions in order to directly test our theory. Moreover, we show that long-term co-culture of breast cancer cells and normal fibroblasts promotes loss of Cav1 and gain of MCT4 in adjacent fibroblasts and increase lactate secretion. These results were validated using the monoculture of each group separately as a control. In this system, we show that metformin inhibits IL-6 and TGFß secretion and re-expresses Cav1 in both cells. However, MCT4 and lactate stayed high after treatment with metformin. In conclusion, our work shows that co-culture with breast cancer cells may cause significant alterations in the phenotype and secretion of normal fibroblasts. Metformin, however, may change this state and affect fibroblasts' acquired phenotypes. Moreover, mitochondrial inhibition by metformin after 8 days of treatment, significantly hinders tumor growth in mouse model of breast cancer.

Efficient Sequential Co-Delivery Nanosystem for Inhibition of Tumor and Tumor-Associated Fibroblast-Induced Resistance and Metastasis.

Purpose: Triple-negative breast cancer (TNBC) is the most lethal subtype of breast cancer. However, the effect of current treatment strategies by inducing tumor cell apoptosis alone is not satisfactory. The growth, metastasis and treatment sensitivity of tumors can be strongly influenced by cancer-associated fibroblasts (CAFs) in the microenvironment. Effective cancer therapies may need to target not only the tumor cells directly but also the CAFs that protect them. Methods: Celastrol and small-sized micelles containing betulinic acid were co-encapsulated into liposomes using the thin-film hydration method (CL@BM). Folic acid was further introduced to modify liposomes as the targeting moiety (F/CL@BM). We established a novel NIH3T3+4T1 co-culture model to mimic the tumor microenvironment and assessed the nanocarrier's inhibitory effects on CAFs-induced drug resistance and migration in the co-culture model. The in vivo biological distribution, fluorescence imaging, biological safety evaluation, and combined therapeutic effect evaluation of the nanocarrier were carried out based on a triple-negative breast cancer model. Results: In the present study, a novel multifunctional nano-formulation was designed by combining the advantages of sequential release, co-loading of tretinoin and betulinic acid, and folic acid-mediated active targeting. As expected, the nano-formulation exhibited enhanced cytotoxicity in different cellular models and effectively increased drug accumulation at the tumor site by disrupting the cellular barrier composed of CAFs by tretinoin. Notably, the co-loaded nano-formulations proved to be more potent in inhibiting tumor growth in mice and also showed better anti-metastatic effects in lung metastasis models compared to the formulations with either drug alone. This novel drug delivery system has the potential to be used to develop more effective cancer therapies. Conclusion: Targeting CAFs with celastrol sensitizes tumor cells to chemotherapy, increasing the efficacy of betulinic acid. The combination of drugs targeting tumor cells and CAFs may lead to more effective therapies against various cancers.

Ripe papaya pectins inhibit the proliferation of colon cancer spheroids and the formation of chemically induced aberrant crypts in rats colons.

Pectins are a class of soluble polysaccharides that can have anticancer properties through several mechanisms. This study aimed to characterize the molecular structure of water-soluble fractions (WSF) derived from ripe and unripe papayas and assess their biological effects in two models: the 3D colon cancer spheroids to measure cell viability and cytotoxicity, and the in vivo model to investigate the inhibition of preneoplastic lesions in rats. WSF yield was slightly higher in ripe papaya, and both samples mainly consisted of pectin. Both pectins inhibited the growth of colon cancer HT29 and HCT116 spheroids. Unripe pectin disturbed HT29/NIH3T3 spheroid formation, decreased HCT116 spheroid viability, and increased spheroid cytotoxicity. Ripe pectin had a more substantial effect on the reduction of spheroid viability for HT29 spheroids. Furthermore, in vivo experiments on a rat model revealed a decrease in aberrant crypt foci (ACF) formation for both pectins and increased apoptosis in colonocytes for ripe papaya pectins. The results suggest potential anticancer properties of papaya pectin, with ripe pectin showing a higher potency.

Pectin wrapped halloysite nanotube reinforced Polycaprolactone films for potential wound healing application.

The current research work focuses on preparing the polycaprolactone (PCL) based nanocomposite films embedded with surface modified Halloysite Nanotube (HNT). The avenue of the study is to unravel the applicability of polymer nanocomposites for wound healing. The flexible property of HNT was taken as the major force to accomplish the addition of biopolymer pectin onto its surface. Functionalization of HNT with pectin has certainly enhanced its binding nature with the polymer. The PCL nanocomposite films were characterized by several promising techniques such as FTIR, XRD, DSC-TGA, FESEM, TEM, AFM, and mechanical properties were too examined along. When compared to the plane PCL film, the nanocomposite films manifested favorable results in terms of mechanical and chemical properties. Additionally, biometric studies such as in-vitro swelling, enzymatic degradation, and hemolysis performed on the films gave extremely good results. The haemolytic percentage recorded for the films exhibited a steady decrease with increasing amount of nanofillers. The MTT assay showed cell proliferation and its increase as the embedded HNT is more in the matrix. Wound closure study performed on NIH3T3 cell line with 1, 3 and 5wt% of films has given a strong proof for the involvement of polymer and HNT in the healing procedure.

Effects of doxorubicin on autophagy in fibroblasts.

Objectives: Doxorubicin (DOX) is a highly effective chemotherapeutic used to treat many adult and pediatric cancers, such as solid tumors, leukemia, lymphomas and breast cancer. It can also cause injuries to multiple organs, including the heart, liver, and brain or kidney, although cardiotoxicity is the most prominent side effect of DOX. In this study, we examined the potential effects of DOX on autophagy activity in two different mouse fibroblasts.Methods: Mouse embryonic fibroblasts (NIH3T3) and mouse primary cardiac fibroblasts (CFs) were treated with DOX to assess changes in the expression of two commonly used autophagy protein markers, LC3II and p62. We also examined the effects of DOX the on expression of key genes that encode components of the molecular machinery and regulators modulating autophagy in response to both extracellular and intracellular signals.Results: We observed that LC3II levels increased and p62 levels decreased following the DOX treatment in NIH3T3 cells. However, similar effects were not observed in primary cardiac fibroblasts. In addition, DOX treatment induced the upregulation of a significant number of genes involved in autophagy in NIH3T3 cells, but not in primary cardiac fibroblasts.Conclusions: Taken together, these results indicate that DOX upregulates autophagy in fibroblasts in a cell-specific manner.

Epithelioid hemangioendothelioma (EHE) with WWTR1::TFE3 gene fusion, a novel fusion variant.

Epithelioid hemangioendothelioma (EHE) is a rare endothelial sarcoma associated with a high incidence of metastases and for which there are no standard treatment options. Based on disease-defining mutations, most EHEs are classified into two subtypes: WWTR1::CAMTA1-fused EHE or YAP1::TFE3-fused EHE. However, rare non-canonical fusions have been identified in clinical samples of EHE cases and are challenging to classify. In this study, we report the identification of a novel WWTR1::TFE3 fusion variant in an EHE patient using targeted RNA sequencing. Histologically, the tumor exhibited hybrid morphological characteristics between WWTR1::CAMTA1-fused EHE and YAP1::TFE3-fused EHE. In addition to the driver fusion, there were six additional secondary mutations identified, including a loss-of-function FANCA mutation. Furthermore, in vitro studies were conducted to investigate the tumorigenic function of the WWTR1::TFE3 fusion protein in NIH3T3 cells and demonstrated that WWTR1::TFE3 promotes colony formation in soft agar. Finally, as the wild-type WWTR1 protein relies on binding the TEAD family of transcription factors to affect gene transcription, mutation of the WWTR1 domain of the fusion protein to inhibit such binding abrogates the transformative effect of WWTR1::TFE3. Overall, we describe a novel gene fusion in EHE with a hybrid histological appearance between the two major genetic subtypes of EHE. Further cases of this very rare subtype of EHE will need to be identified to fully elucidate the clinical and pathological characteristics of this unusual subtype of EHE.

Oxidized alginate-gelatin (ADA-GEL)/silk fibroin/Cu-Ag doped mesoporous bioactive glass nanoparticle-based hydrogels for potential wound care treatments.

The present work focuses on developing 5% w/v oxidized alginate (alginate di aldehyde, ADA)-7.5% w/v gelatin (GEL) hydrogels incorporating 0.25% w/v silk fibroin (SF) and loaded with 0.3% w/v Cu-Ag doped mesoporous bioactive glass nanoparticles (Cu-Ag MBGNs). The microstructural, mechanical, and biological properties of the composite hydrogels were characterized in detail. The porous microstructure of the developed ADA-GEL based hydrogels was confirmed by scanning electron microscopy, while the presence of Cu-Ag MBGNs in the synthesized hydrogels was determined using energy dispersive x-ray spectroscopy. The incorporation of 0.3% w/v Cu-Ag MBGNs reduced the mechanical properties of the synthesized hydrogels, as investigated using micro-tensile testing. The synthesized ADA-GEL loaded with 0.25% w/v SF and 0.3% w/v Cu-Ag MBGNs showed a potent antibacterial effect againstEscherichia coliandStaphylococcus aureus. Cellular studies using the NIH3T3-E1 fibroblast cell line confirmed that ADA-GEL films incorporated with 0.3% w/v Cu-Ag MBGNs exhibited promising cellular viability as compared to pure ADA-GEL (determined by WST-8 assay). The addition of SF improved the biocompatibility, degradation rate, moisturizing effects, and stretchability of the developed hydrogels, as determinedin vitro. Such multimaterial hydrogels can stimulate angiogenesis and exhibit desirable antibacterial properties. Therefore further (in vivo) tests are justified to assess the hydrogels' potential for wound dressing and skin tissue healing applications.

Synergistic Effect of Nano Strontium Titanate Coating and Ultraviolet C Photofunctionalization on Osteogenic Performance and Soft Tissue Sealing of poly(ether-ether-ketone).

This study aimed to evaluate the bioactivity of poly(ether ether ketone) (PEEK) after surface modification by persistent photoconductive strontium titanate (SrTiO3) magnetron sputtering and ultraviolet (UV) C irradiation. According to the different modifications, the PEEK specimens were randomly divided into five groups (n = 38/group): PEEK, Sr100-PEEK, Sr200-PEEK, UV/PEEK, and UV/Sr200-PEEK. Then, the specimens of Sr100-PEEK and Sr200-PEEK groups were, respectively, coated with 100 and 200 nm thickness photocatalyst SrTiO3 on the PEEK surface by magnetron sputtering. Subsequently, UV-C light photofunctionalized the specimens of PEEK and Sr200-PEEK groups to form UV/PEEK and UV/Sr200-PEEK groups. The specimens were characterized by a step meter, scanning electron microscopy (SEM), atomic force microscopy (AFM), energy dispersive X-ray spectroscopy (EDX), and a water contact angle meter. The release test of the Sr ion was performed by inductively coupled plasma mass spectrometry (ICP-MS). In vitro study, osteogenic activity (MC3T3-E1 osteoblast-like cells) and epithelial and connective tissue attachment (gingival epithelial cells GE1 and fibroblasts NIH3T3) were analyzed in five groups. Surface morphology of the specimens was changed after coating, and the Sr content on the Sr-PEEK surface was increased with increasing coating thickness. In addition, the contact angle was increased significantly after magnetron sputtering. After UV-C photofunctionalization, the content of surface elements changed and the contact angle was decreased. The release of Sr ion was sustained, and the final cumulative release amount did not exceed the safety limit. In vitro experiments showed that SrTiO3 improved the cell activity of MC3T3-E1 and UV-C irradiation further enhanced the osteogenic performance of PEEK. Besides, UV-C irradiation also significantly promoted the cell viability, development, and expression of adhesion proteins of GE1 and NIH3T3 on PEEK. The present investigation demonstrated that nano SrTiO3 coating with UV-C photofunctionalization synergistically enhanced the osteogenic properties and soft tissue sealing function of PEEK in vitro.

A stochastic model for topographically influenced cell migration.

Migrating cells traverse a range of topographic configurations presented by the native extracellular environment to conduct their physiologic functions. It is well documented cells can modulate their behaviour in response to different topographic features, finding promising applications in biomaterial and bioimplant design. It is useful, in these areas of research, to be able to predict which topographic arrangements could be used to promote certain patterns of migration prior to laboratory experimentation. Despite a profusion of study and interest shown in these fields by experimentalists, the related modelling literature is as yet relatively sparse and tend to focus more on either cell-matrix interaction or morphological responses of cells. We propose a mathematical model for individual cell migration based on an Ornstein-Uhlenbeck process, and set out to see if the model can be used to predict migration patterns on 2-d isotropic and anisotropic topographies, whose characteristics can be broadly described as either uniform flat, uniform linear with variable ridge density or non-uniform disordered with variable feature density. Results suggest the model is capable of producing realistic patterns of migration for flat and linear topographic patterns, with calibrated output closely approximating NIH3T3 fibroblast migration behaviour derived from an experimental dataset, in which migration linearity increased with ridge density and average speed was highest at intermediate ridge densities. Exploratory results for non-uniform disordered topographies suggest cell migration patterns may adopt disorderedness present in the topography and that 'distortion' introduced to linear topographic patterns may not impede linear guidance of migration, given its magnitude is bounded within certain limits. We conclude that an Ornstein-Uhlenbeck based model for topographically influenced migration may be useful to predict patterns of migration behaviour for certain isotropic (flat) and anisotropic (linear) topographies in the NIH3T3 fibroblast cell line, but additional investigation is required to predict with confidence migration patterns for non-uniform disordered topographic arrangements.

The non-vesicle cell-free DNA (cfDNA) induces cell transformation associated with horizontal DNA transfer.

BACKGROUND: Cell-free DNA (cfDNA) is a source for liquid biopsy used for cancer diagnosis, therapy selection, and disease monitoring due to its non-invasive nature and ease of extraction. However, cfDNA also participates in cancer development and progression by horizontal transfer. In humans, cfDNA circulates complexed with extracellular vesicles (EV) and macromolecular complexes such as nucleosomes, lipids, and serum proteins. The present study aimed to demonstrate whether cfDNA not associated with EV induces cell transformation and tumorigenesis. METHODS: Supernatant of the SW480 human colon cancer cell line was processed by ultracentrifugation to obtain a soluble fraction (SF) and a fraction associated with EV (EVF). Primary murine embryonic fibroblast cells (NIH3T3) underwent passive transfection with these fractions, and cell proliferation, cell cycle, apoptosis, cell transformation, and tumorigenic assays were performed. Next, cfDNA was analyzed by electronic microscopy, and horizontal transfer was assessed by human mutant KRAS in recipient cells via PCR and recipient cell internalization via fluorescence microscopy. RESULTS: The results showed that the SF but not the EVF of cfDNA induced proliferative and antiapoptotic effects, cell transformation, and tumorigenesis in nude mice, which were reduced by digestion with DNAse I and proteinase K. These effects were associated with horizontal DNA transfer and cfDNA internalization into recipient cells. CONCLUSIONS: The results suggest pro-tumorigenic effects of cfDNA in the SF that can be offset by enzyme treatment. Further exploration of the horizontal tumor progression phenomenon mediated by cfDNA is needed to determine whether its manipulation may play a role in cancer therapy.

Murine leukemia virus infection of non-dividing dendritic cells is dependent on nucleoporins.

Retroviral reverse transcription starts within the capsid and uncoating and reverse transcription are mutually dependent. There is still debate regarding the timing and cellular location of HIV's uncoating and reverse transcription and whether it occurs solely in the cytoplasm, nucleus or both. HIV can infect non-dividing cells because there is active transport of the preintegration complex (PIC) across the nuclear membrane, but Murine Leukemia Virus (MLV) is thought to depend on cell division for replication and whether MLV uncoating and reverse transcription is solely cytoplasmic has not been studied. Here, we used NIH3T3 and primary mouse dendritic cells to determine where the different stages of reverse transcription occur and whether cell division is needed for nuclear entry. Our data strongly suggest that in both NIH3T3 cells and dendritic cells (DCs), the initial step of reverse transcription occurs in the cytoplasm. However, we detected MLV RNA/DNA hybrid intermediates in the nucleus of dividing NIH3T3 cells and non-dividing DCs, suggesting that reverse transcription can continue after nuclear entry. We also confirmed that the MLV PIC requires cell division to enter the nucleus of NIH3T3 cells. In contrast, we show that MLV can infect non-dividing primary DCs, although integration of MLV DNA in DCs still required the viral p12 protein. Knockdown of several nuclear pore proteins dramatically reduced the appearance of integrated MLV DNA in DCs but not NIH3T3 cells. Additionally, MLV capsid associated with the nuclear pore proteins NUP358 and NUP62 during infection. These findings suggest that simple retroviruses, like the complex retrovirus HIV, gain nuclear entry by traversing the nuclear pore complex in non-mitotic cells.

Facile preparation of self-healing hydrogels based on chitosan and PVA with the incorporation of curcumin-loaded micelles for wound dressings.

The increased demand for improved strategies for wound healing has, in recent years, motivated the development of multifunctional hydrogels with favorable bio-compatibility and antibacterial properties. To this regard, the current study presented the design of a novel self-healing composite hydrogel that could perform as wound dressing for the promotion of wound healing. The composite hydrogels were composed of polyvinyl alcohol (PVA), borax and chitosan functionalized with sialic acid (SA-CS) and curcumin loaded pluronic F127 micelles. The hydrogels were formed through the boronic ester bond formation between PVA, SA-CS and borax under physiological conditions and demonstrated adjustable mechanical properties, gelation kinetics and antibacterial properties. When incubating with NIH3T3 cells, the hydrogels also demonstrated good biocompatibility. These aspects offer a promising foundation for their prospective applications in developing clinical materials for wound healing.

PTEN activates chaperone-mediated autophagy to regulate metabolism.

PTEN is a negative modulator of the INS-PI3K-AKT pathway and is an essential regulator of metabolism and cell growth. PTEN is one of the most commonly mutated tumor suppressors in cancer. However, PTEN overexpression extends the lifespan of both sexes of mice. We recently showed that PTEN is necessary and sufficient to activate chaperone-mediated autophagy (CMA) in the mouse liver and cultured cells. Selective protein degradation via CMA is required to suppress glycolysis and fatty acid synthesis when PTEN is overexpressed. Thus, activation of CMA downstream of PTEN might modulate health and metabolism through selective degradation of key metabolic enzymes.