Amniotic Membrane-Derived Multichannel Hydrogels for Neural Tissue Repair.

In the pursuit of advancing neural tissue regeneration, biomaterial scaffolds have emerged as promising candidates, offering potential solutions for nerve disruptions. Among these scaffolds, multichannel hydrogels, characterized by meticulously designed micrometer-scale channels, stand out as instrumental tools for guiding axonal growth and facilitating cellular interactions. This study explores the innovative application of human amniotic membranes modified with methacryloyl domains (AMMA) in neural stem cell (NSC) culture. AMMA hydrogels, possessing a tailored softness resembling the physiological environment, are prepared in the format of multichannel scaffolds to simulate native-like microarchitecture of nerve tracts. Preliminary experiments on AMMA hydrogel films showcase their potential for neural applications, demonstrating robust adhesion, proliferation, and differentiation of NSCs without the need for additional coatings. Transitioning into the 3D realm, the multichannel architecture fosters intricate neuronal networks guiding neurite extension longitudinally. Furthermore, the presence of synaptic vesicles within the cellular arrays suggests the establishment of functional synaptic connections, underscoring the physiological relevance of the developed neuronal networks. This work contributes to the ongoing efforts to find ethical, clinically translatable, and functionally relevant approaches for regenerative neuroscience.

Upside-Down Preference in the Forskolin-Induced In Vitro Differentiation of 50B11 Sensory Neurons: A Morphological Investigation by Label-Free Non-Linear Microscopy.

In this study, we revealed a peculiar morphological feature of 50B11 nociceptive sensory neurons in in vitro culture related to the forskolin-induced differentiation of these cells growing upside-down on cover glass supports. Multi-photon non-linear microscopy was applied to monitor increased neurite arborization and elongation. Under live and unstained conditions, second harmonic generation (SHG) microscopy could monitor microtubule organization inside the cells while also correlating with the detection of cellular multi-photon autofluorescence, probably derived from mitochondria metabolites. Although the differentiated cells of each compartment did not differ significantly in tubulin or multi-photon autofluorescence contents, the upturned neurons were more elongated, presenting a higher length/width cellular ratio and longer neurites, indicative of differentiated cells. SHG originating from the axons' microtubules represented a proper tool to study neurons' inverted culture in live conditions without exogenous staining. This work represents the first instance of examining neuronal cell lines growing and differentiated in an upside-down orientation, allowing a possible improvement of 50B11 as a model in physiology studies of sensory neurons in peripheric nervous system disease (e.g., Fabry disease, Friedreich ataxia, Charcot-Marie-Tooth, porphyria, type 1 diabetes, Guillain-Barré syndrome in children) and analgesic drug screening.

Interfacing reduced graphene oxide with an adipose-derived extracellular matrix as a regulating milieu for neural tissue engineering.

Enthralling evidence of the potential of graphene-based materials for neural tissue engineering is motivating the development of scaffolds using various structures related to graphene such as graphene oxide (GO) or its reduced form. Here, we investigated a strategy based on reduced graphene oxide (rGO) combined with a decellularized extracellular matrix from adipose tissue (adECM), which is still unexplored for neural repair and regeneration. Scaffolds containing up to 50 wt% rGO relative to adECM were prepared by thermally induced phase separation assisted by carbodiimide (EDC) crosslinking. Using partially reduced GO enables fine-tuning of the structural interaction between rGO and adECM. As the concentration of rGO increased, non-covalent bonding gradually prevailed over EDC-induced covalent conjugation with the adECM. Edge-to-edge aggregation of rGO favours adECM to act as a biomolecular physical crosslinker to rGO, leading to the softening of the scaffolds. The unique biochemistry of adECM allows neural stem cells to adhere and grow. Importantly, high rGO concentrations directly control cell fate by inducing the differentiation of both NE-4C cells and embryonic neural progenitor cells into neurons. Furthermore, primary astrocyte fate is also modulated as increasing rGO boosts the expression of reactivity markers while unaltering the expression of scar-forming ones.

CXCR4 and JUNB double-positive disseminated tumor cells are detected frequently in breast cancer patients at primary diagnosis.

BACKGROUND: The chemokine receptor CXCR4 and the transcription factor JUNB, expressed on a variety of tumor cells, seem to play an important role in the metastatic process. Since disseminated tumor cells (DTCs) in the bone marrow (BM) have been associated with worse outcomes, we evaluated the expression of CXCR4 and JUNB in DTCs of primary, nonmetastatic breast cancer (BC) patients before the onset of any systemic treatment. METHODS: Bilateral BM (10 ml) aspirations of 39 hormone receptor (HR)-positive, HER2-negative BC patients were assessed for the presence of DTCs using the following combination of antibodies: pan-cytokeratin (A45-B/B3)/CXCR4/JUNB. An expression pattern of the examined proteins was created using confocal laser scanning microscopy, Image J software and BC cell lines. RESULTS: CXCR4 was overexpressed in cancer cells and DTCs, with the following hierarchy of expression: SKBR3 > MCF7 > DTCs > MDA-MB231. Accordingly, the expression pattern of JUNB was: DTCs > MDA-MB231 > SKBR3 > MCF7. The mean intensity of CXCR4 (6411 ± 334) and JUNB (27725.64 ± 470) in DTCs was statistically higher compared with BM hematopoietic cells (2009 ± 456, p = 0.001; and 11112.89 ± 545, p = 0.001, respectively). The (CXCR4+JUNB+CK+) phenotype was the most frequently detected [90% (35/39)], followed by the (CXCR4-JUNB+CK+) phenotype [36% (14/39)]. However, (CXCR4+JUNB-CK+) tumor cells were found in only 5% (3/39) of patients. Those patients harboring DTCs with the (CXCR4+JUNB+CK+) phenotype revealed lower overall survival (Cox regression: p = 0.023). CONCLUSIONS: (CXCR4+JUNB+CK+)-expressing DTCs, detected frequently in the BM of BC patients, seem to identify a subgroup of patients at higher risk for relapse that may be considered for close follow up.

Immunomodulatory Potential of Chitosan-graft-poly(ε-caprolactone) Copolymers toward the Polarization of Bone-Marrow-Derived Macrophages.

In tissue engineering, the use of biomaterials as templates or scaffolds to guide tissue development in vivo provokes the inevitable action of the immune system of the host. This induced immune response often determines the success of the scaffold, including angiogenesis and regeneration or failure causing inflammation and fibrosis. Therefore, it is crucial to predict or even better to promote the proper immune response following implantation. The aim of the present study was to evaluate the immunomodulatory potential of chitosan-graft-poly(ε-caprolactone) copolymers (CS-g-PCL) by analyzing the differentiation of primary bone marrow derived macrophages (BMDM) cultured in vitro on copolymer thin films. In order to evaluate the role of the chitosan content of the copolymer on macrophage polarization, two different copolymers containing 50 and 78% w/w chitosan were studied. Our data from cytokines secretion detection by ELISA show that the CS-g-PCL copolymer significantly decreases the secretion of the inducible levels of pro-inflammatory cytokines IL-12/23 by 31% ± 6, and thus possesses anti-inflammatory ability. Moreover, this anti-inflammatory action is correlated with the increased chitosan content of the copolymer. In addition, the CS-g-PCL copolymer significantly enhances the production of Arg1, the hallmark of M2 polarized macrophages, as shown by semiquantitative RT-PCR analysis, and this enhancement is 4-fold higher for the copolymer with the lower chitosan content. Although further in vivo experimentation is required to predict the outcome of the in situ engraftment of the copolymer, our results so far suggest that the CS-g-PCL copolymers possess anti-inflammatory activity and favor the transition of M1 to M2 macrophages, which are essential prerequisites for proper tissue remodeling.

Expression of MIF and CD74 in leukemic cell lines: correlation to DR expression destiny.

Invariant chain (Ii) or CD74 is a non-polymorphic glycoprotein, which apart from its role as a chaperone dedicated to MHCII molecules, is known to be a high-affinity receptor for macrophage migration inhibitory factor (MIF). The present study aimed to define the roles of CD74 and MIF in the immune surveillance escape process. Towards this direction, the cell lines HL-60, Raji, K562 and primary pre-B leukemic cells were examined for expression and secretion of MIF. Flow cytometry analysis detected high levels of MIF and intracellular/membrane CD74 expression in all leukemic cells tested, while MIF secretion was shown to be inversely proportional to intracellular HLA-DR (DR) expression. In the MHCII-negative cells, IFN-γ increased MIF expression and induced its secretion in HL-60 and K562 cells, respectively. In K562 cells, CD74 (Iip33Iip35) was shown to co-precipitate with HLA-DOß (DOß), inhibiting thus MIF or DR binding. Induced expression of DOα in K562 (DOα-DOß+) cells in different transfection combinations decreased MIF expression and secretion, while increasing surface DR expression. Thus, MIF could indeed be part of the antigen presentation process.

DOα⁻ß⁺ expression in favor of HLA-DR engagement in exosomes.

The expression of DOß and not DOα, in addition to the high intracellular DR, low DM levels and absence of surface DR expression in K562 and HL-60 cells introduce alternative regulatory pathways in DR trafficking and consequently the antigen presentation process. The present study attempted to define the naturally occurring DOα negative state and explain the role of DOß in the intracellular DR accumulation in K562 and HL-60 cells. Despite the absence of DOα, the DOß chain was detected in the endosomal compartments. The lack of DOα was found to be partially responsible for the absence of DR from the cell membrane since stable K562-DOα transfectants allowed expression of membrane DR. This expression could be significantly increased upon DM induction by IFN-γ, indicating that DM was another limiting factor for the migration of DR to the cell surface of K562 and HL-60 cells. Furthermore, intracellular DR co-localized with the exosome specific marker CD9, while culture supernatants were shown to contain exosome-engaged and exosome free DR activity as evaluated by SDS-page followed by western blot, ELISA and transmission electron microscopy analysis. These findings indicated that in DOα⁻ß⁺ cells, DR molecules were programmed to secretion rather than surface expression. The presented results provide novel regulatory processes as to DR trafficking, avoiding expression to the cell surface.

Glucocorticoid and proteasome inhibitor impact on the leukemic lymphoblast: multiple, diverse signals converging on a few key downstream regulators.

Twenty years ago a proteasome inhibitor was suggested as therapy for glucocorticoid-resistant multiple myeloma, a disease that involves terminally differentiated B cells. Since then, research has proven that it has utility on a number of tumors resistant to chemotherapy. Hematologic malignancy, however, often involves lesser differentiated cells, which have a high potential to modulate their intrinsic machinery and thereby activate alternative rescue pathways. A corresponding multiplicity of therapies is not always practical. One approach to conditions with heterogeneous physiology is to identify key biochemical mediators, thereby reducing the number of treatment targets. Results from several ongoing studies indicate convergence of genomically diverse signal pathways to a limited number of key downstream regulators of apoptosis. Convergence of pathways can be exploited to address the problem of genetic heterogeneity in acute leukemia: this would mean treating multiple molecular aberrations with fewer drugs and enhanced therapeutic benefit.

Characterization of intracellular HLA-DR, DM and DO profile in K562 and HL-60 leukemic cells.

Surface class-II antigen expression fires-up the antigen presentation process and development of immune response. The absence of surface HLA-DR is used in various systems to avoid immune recognition. Most leukemic cells use such mechanism to escape immune surveillance. Here, K562 and HL-60 leukemic cells were examined as to intracellular HLA-DR, -DM and -DO expression, if any. Immunofluorescence scored by UV-microscopy, flow cytometry or confocal microscope analysis detected intracellular pools of HLA-DR, -DO and to a lesser degree HLA-DM, whereas sub-cellular fractionation localized these molecules within endosomes. RT-PCR experiments revealed the presence of HLA-DRalphabeta, HLA-DMalphabeta and HLA-DObeta but not HLA-DOalpha transcripts. Despite the absence of the HLA-DOalpha chain, stable transfectants of K562 with a full length HLA-DObeta-EGFP construct showed that DObeta chain could be translocated to endosomes and form stable complexes with HLA-DR. Such complexes could be responsible for arresting HLA-DR molecules within endosomes, maintaining their surface class-II negative state.