Biology subjects

Donnelly, P. S.

Publications and source records attributed to Donnelly, P. S..

4 recordsLinked to original sources

bioRxiv2023

A patient-derived blood-brain barrier model for screening copper bis(thiosemicarbazone) complexes as potential therapeutics in Alzheimer's disease

Alzheimers disease (AD) is the most prevalent cause of dementia characterised by progressive cognitive decline. Addressing neuroinflammation represents a promising therapeutic avenue to treat AD, however, the development of effective anti-neuroinflammatory compounds is often hindered by their limited blood-brain barrier (BBB) permeability. Consequently, there is an urgent need for accurate, preclinical AD patient-specific BBB models to facilitate the early identification of immunomodulatory drugs capable of efficiently crossing human AD BBB. This study presents a unique approach to BBB drug permeability screening as it utilises the familial AD patient-derived induced brain endothelial-like cells (iBEC)-based model, which exhibits increased disease relevance and serves as an improved BBB drug permeability assessment tool when compared to traditionally employed in vitro models. To demonstrate its utility as a small molecule drug candidate screening platform, we investigated the effects of CuII(atsm) and a library of novel metal bis(thiosemicarbazone) complexes - a class of compounds exhibiting anti-neuroinflammatory therapeutic potential in neurodegenerative disorders. By evaluating the toxicity, cellular accumulation and permeability of those compounds in the AD patient-derived iBEC, we have identified CuII(dtsm) as an emerging drug candidate with enhanced transport across the AD BBB. Furthermore, we have developed a multiplex approach where AD patient-derived iBEC were combined with immune modulators TNF and IFN{gamma} to establish an in vitro model representing the characteristic neuroinflammatory phenotype at the patients BBB. Here we observed that treatment with CuII(dtsm) not only reduced the expression of proinflammatory cytokine genes but also reversed the detrimental effects of TNF and IFN{psi} on the integrity and function of the AD iBEC monolayer. This suggests a novel pathway through which copper bis(thiosemicarbazone) complexes may exert neurotherapeutic effects in AD by mitigating BBB neuroinflammation and related BBB integrity impairment. Together, the presented model provides an effective and easily scalable in vitro BBB platform for screening AD drug candidates. Its improved translational potential makes it a valuable tool for advancing the development of metal-based compounds aimed at modulating neuroinflammation in AD. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=199 HEIGHT=200 SRC="FIGDIR/small/554047v1_ufig1.gif" ALT="Figure 1"> View larger version (71K): org.highwire.dtl.DTLVardef@1d949b5org.highwire.dtl.DTLVardef@7629ccorg.highwire.dtl.DTLVardef@1b2125dorg.highwire.dtl.DTLVardef@1d3cde1_HPS_FORMAT_FIGEXP M_FIG C_FIG

neuroscience↗

bioRxiv2023

A General Fluorescence-Based Method for Quantifying and Mapping Biomolecular Polarity In Vitro and In Cells

Spatial discretization of biomolecules in the complex cellular environment is crucial for biomolecular form and function. The ability to better understand the driving force of spatial discretization of biomolecules in the complex cellular matrix remains a challenging task. We report on the robust polarity sensitive solvatochromic probe, FLAM, in conjunction with spectral phasor analysis as a general method for studying environmental polarity in biological systems. We find that phase separated proteins of SFPQ have distinct polarity depending on the type of phase separation occurring, suggesting that polarity plays a role in the formation of phase separated condensates. When using FLAM in cells, distinct subcellular environmental polarity distribution but similar trend of changes is observed for cells under similar type of stressors. Taken together, our method puts forth an exciting development in the tool set for the study of phase separation.

biochemistry↗

bioRxiv2022

Microglial ferroptotic stress causes non-cell autonomous neuronal death

BackgroundFerroptosis is a form of regulated cell death characterised by lipid peroxidation as the terminal endpoint and a requirement for iron. Although it protects against cancer and infection, ferroptosis is also implicated in causing neuronal death in degenerative diseases of the central nervous system (CNS). The precise role for ferroptosis in causing neuronal death is yet to be fully resolved. MethodsTo elucidate the role of ferroptosis in neuronal death we utilised co-culture and conditioned medium transfer experiments involving microglia, astrocytes and neurones. We ratified clinical significance of our cell culture findings via assessment of human CNS tissue from cases of the fatal, paralysing neurodegenerative condition of amyotrophic lateral sclerosis (ALS). Finally, we utilised the SOD1G37R mouse model of ALS and a novel CNS-permeant ferroptosis inhibitor to verify pharmacological significance in vivo. ResultsWe found that sublethal ferroptotic stress selectively affecting microglia triggers an inflammatory cascade that results in non-cell autonomous neuronal death. Central to this cascade is the conversion of astrocytes to a neurotoxic state. We show that spinal cord tissue from cases of ALS exhibits a signature of ferroptosis that encompasses atomic, molecular and biochemical features. Moreover, a molecular correlation between ferroptosis and neurotoxic astrocytes evident in ALS-affected spinal cord is recapitulated in the SOD1G37R mouse model where treatment with the novel, CNS-permeant ferroptosis inhibitor, CuII(atsm), ameliorated these markers and was neuroprotective. ConclusionsBy showing that microglia responding to sublethal ferroptotic stress culminates in non-cell autonomous neuronal death, our results implicate microglial ferroptotic stress as a rectifiable cause of neuronal death in neurodegenerative disease. As ferroptosis is currently primarily regarded as an intrinsic cell death phenomenon, these results introduce an entirely new pathophysiological role for ferroptosis in disease.

neuroscience↗

bioRxiv2020

Disrupted copper availability in sporadic ALS: Implications for CuII(atsm) as a treatment option

ObjectiveThe copper compound CuII(atsm) is in phase 2/3 testing for treatment of the neurodegenerative disease amyotrophic lateral sclerosis (ALS). CuII(atsm) consistently and reproducibly ameliorates neurodegeneration in mutant SOD1 mouse models of ALS where its neuroprotective activity has been ascribed in part to improving availability of copper to essential cuproenzymes. However, SOD1 mutations cause only ~2% of ALS cases with most cases being of unknown aetiology. Therapeutic pertinence of CuII(atsm) to sporadic ALS is therefore unclear. MethodsWe assayed post-mortem spinal cord tissue from sporadic cases of ALS for the anatomical and biochemical distribution of copper, the expression of genes involved in copper handling, and the activities of cuproenzymes. ResultsThe natural distribution of copper is disrupted in sporadic ALS. The ALS-affected tissue has a molecular signature consistent with an unsatiated requirement for copper and cuproenzyme activity is affected. Copper levels are decreased in the ventral grey matter, the primary anatomical site of neuronal loss in ALS. InterpretationMice expressing mutant SOD1 recapitulate salient features of ALS. The unsatiated requirement for copper that is evident in these mice is a biochemical target for CuII(atsm). Evidences provided here for disrupted copper bioavailability in human cases of sporadic ALS indicate that a therapeutic mechanism for CuII(atsm) involving copper bioavailability is pertinent to sporadic cases of ALS, and not just those involving mutant SOD1.

neuroscience↗