Biology subjects

Moore, M. A.

Publications and source records attributed to Moore, M. A..

3 recordsLinked to original sources

bioRxiv2024

Cytoprotective and Neuroinductive Effects of Thiol-Containing Simple Signaling Molecules

Around 20 million Americans, mostly young adults, have suffered from a peripheral nerve injury due to trauma or a medical condition. However, prevailing treatments, including those that employ exogenous growth factors, often exhibit drawbacks outweighing their benefits, highlighting the need for novel solutions. Non-complex agents that govern bioactivity, termed simple signaling molecules (SSMs), offer an exciting alternative when compared to traditional approaches due to their small size, ready availability, and influence on cellular pathways. This study explores the cytoprotective and neuroinductive effects of three thiol-containing SSMs: hydrogen sulfide (H2S), n-acetyl cysteine (NAC), and glutathione (GSH). Neural stem cells (NE-4Cs) were exposed to toxic levels of hydrogen peroxide (H2O2) while supplemented with different concentrations of H2S, NAC, or GSH to assess their cytoprotective effects. To study the neuroinductivity of H2S, NAC, and GSH with NE-4Cs, immunofluorescence microscopy for an early neuronal marker, {beta}3-tubulin, was employed to determine stem cell neural differentiation. Significant cytoprotection was found for NAC (2 - 8 mM) and GSH (2 - 12 mM), while H2S showed limited protective effects. Interestingly, the opposite result was observed for neuroinductivity as only H2S (7.75 - 125 M) achieved a desirable effect while NAC and GSH had minimal impact on neural differentiation. This research establishes therapeutic concentration ranges of H2S, NAC, and GSH for future drug delivery systems targeting neural regeneration, especially for peripheral nerve injuries. LAY SUMMARYApproximately 20 million Americans, mainly young adults, suffer from peripheral nerve injuries, necessitating new effective treatments. Currently emerging approaches, including growth factor-based therapies, unfortunately face considerable limitations. This study explores the potential of simple signaling molecules (SSMs) - small, readily available agents - specifically hydrogen sulfide (H2S), n-acetyl cysteine (NAC), and glutathione (GSH) for their potential to be used to address issues underlying peripheral nerve injuries. Our findings reveal NAC and GSH have cytoprotective effects, whereas H2S is neuroinductive. This research identifies optimal concentrations for future drug delivery targeting neural regeneration, especially beneficial for peripheral nerve injuries. FUTURE WORKSUpcoming investigation will concentrate on exploiting the potential of novel SSM-releasing monomers within degradable polymeric systems. This involves defining therapeutic windows and optimizing polymer chemistry to induce desired cytoprotective and neuroinductive effects in neural stem cells, crucial for peripheral nerve injury repair. Emphasizing controlled release, this approach holds promise for developing advanced therapeutic strategies utilizing H2S, NAC, and/or GSH in nerve guidance conduits. GRAPHICAL ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=108 SRC="FIGDIR/small/597935v1_ufig1.gif" ALT="Figure 1"> View larger version (38K): org.highwire.dtl.DTLVardef@187657dorg.highwire.dtl.DTLVardef@17ffa9org.highwire.dtl.DTLVardef@191dc67org.highwire.dtl.DTLVardef@11d0fd2_HPS_FORMAT_FIGEXP M_FIG C_FIG

bioengineering↗

bioRxiv2019

Increased cell size, structural complexity and migration of cancer cells acquiring fibroblast organelles by cell-projection pumping

We recently described a hydrodynamic mechanism for cytoplasmic transfer between cells, termed cell-projection pumping (CPP). Earlier image analysis related altered SAOS-2 osteosarcoma cell morphology, to what we now recognize as CPP uptake of fibroblast cytoplasm. We here examine SAOS-2 phenotype following co-culture with human dermal fibroblasts (HDF) in which organelles were pre-labelled with a fluorescent lipophilic marker. Fluorescence activated cell sorting (FACS) analysis was performed of HDF and SAOS-2, cultured either alone or together. FACS forward scatter is proportionate to cell size, and increased for SAOS-2 with high levels of HDF fluorescence uptake (p < 0.004). FACS side scatter is proportionate to internal cell complexity, and increased in SAOS-2 with increasing uptake of HDF fluorescence (p < 0.004), consistent with uptake of HDF organelles. Scratch migration assays revealed that HDF migrated more quickly than SAOS-2 in both isolated cell culture, and following co-culture (p < 0.004). Notably, SAOS-2 with high levels of HDF labelling migrated faster compared with SAOS-2 with low HDF labelling (p < 0.008). A slight and unconvincing reduction in SAOS-2 proliferation was seen (p < 0.02). Similar results were obtained in single additional experiments with A673 and H312 cancer cells. Forward and side scatter results suggest organellar transfer by CPP increases cancer cell morphological diversity. This may contribute to histological pleomorphism relevant to cancer diagnosis and prognosis. Also, increased migration of sub-populations of cancer cells with high CPP organellar uptake, may contribute to invasion and metastasis in-vivo. We thus suggest relevance of CPP to cancer diagnosis and progression.

cancer biology↗

bioRxiv2019

Cell-projection pumping: A hydrodynamic cell-stiffness dependent mechanism for cytoplasmic transfer between mammalian cells

We earlier reported cytoplasmic fluorescence exchange between cultured human fibroblasts (Fib) and malignant cells (MC). Others report similar transfer via either tunneling nanotubes (TNT) or shed membrane vesicles and this changes the phenotype of recipient cells. Our current time-lapse microscopy showed most exchange was from Fib into MC, with less in the reverse direction. Although TNT were seen, we were surprised transfer was not via TNT, but was instead via fine and often branching cell projections that defied direct visual resolution because of their size and rapid movement. Their structure was revealed nonetheless, by their organellar cargo and the grooves they formed indenting MC, while this was consistent with holotomography. Discrete, rapid and highly localized transfer events, evidenced against a role for shed vesicles. Transfer coincided with rapid retraction of the cell-projections, suggesting a hydrodynamic mechanism. Increased hydrodynamic pressure in retracting cell-projections normally returns cytoplasm to the cell body. We hypothesize cell-projection pumping (CPP), where cytoplasm in retracting cell-projections partially equilibrates into adjacent recipient cells via micro-fusions that form temporary inter-cellular cytoplasmic continuities. We tested plausibility for CPP by combined mathematical modelling, comparison of predictions from the model with experimental results, and then computer simulations based on experimental data. The mathematical model predicted preferential CPP into cells with lower cell stiffness, expected from equilibration of pressure towards least resistance. Predictions from the model were satisfied when Fib were co-cultured with MC, and fluorescence exchange related with cell stiffness by atomic force microscopy. When transfer into 5000 simulated recipient MC or Fib was studied in computer simulations, inputting experimental cell stiffness and donor cell fluorescence values generated transfers to simulated recipient cells similar to those seen by experiment. We propose CPP as a potentially novel mechanism in mammalian inter-cellular cytoplasmic transfer and communication. SIGNIFICANCETime-lapse observations of co-cultured cells led us to hypothesize what we believe to be a novel hydrodynamic mechanism transferring cytoplasm between cells. Similar transfer by other mechanisms markedly affects cell behavior. Combined mathematical modelling, satisfaction of predictions from the mathematical model in cell culture experiments, and separate computer simulations that generate outcomes similar to experimental observations, support our hypothesized mechanism.

cell biology↗