Biology subjects

Ratcliffe, P.

Publications and source records attributed to Ratcliffe, P..

4 recordsLinked to original sources

bioRxiv2026

Targeting PFKFB3 Metabolic Gatekeeping of β-Cell Dysfunctional States Enables Durable Glucose Tolerance in Type 2 Diabetes

Progressive {beta}-cell dysfunction underlies type 2 diabetes (T2D), yet existing therapies fail to correct the dysfunctional cellular states that accumulate during disease progression. We show that pharmacological inhibition of PFKFB3 markedly reduced the population of PFKFB3 dysfunctional {beta}-cells while preserving functional islet mass, consistent with selective depletion or phenotypic reprogramming of compromised {beta}-cells. In transgenic diabetic mice expressing human IAPP, PFKFB3 inhibitor AZ67 improved glucose-stimulated insulin secretion and glucose tolerance through a mechanism consistent with direct restoration of {beta}-cell function and distinct from incretin-based therapy. Critically, glycemic improvement persisted after treatment withdrawal, consistent with durable remodeling of islet functional states rather than transient pharmacological suppression. In human islet microtissues under glucotoxic and cytokine stress, AZ67 and its analogue AZ26 improved insulin secretion and proinsulin processing in a stress- and compound-dependent manner while reducing PFKFB3 dysfunctional endocrine populations. Transcriptomic profiling identified suppression of inflammatory programs and activation of cholesterol homeostasis and adaptive metabolic pathways. These findings establish PFKFB3 inhibition as a potential disease-modifying therapeutic strategy for T2D.

cell biology↗

bioRxiv2026

Lack of effect of physiological oxidative stress on N-terminal cysteine dependent proteolysis

Oxidative post-translational modifications on the sulfhydryl group of cysteines can occur spontaneously or enzymatically. The dioxygenation of N-terminal cysteines has emerged as a new oxygen sensing paradigm, catalysed by 2-aminoethanethiol dioxygenase (ADO) in mammals. Conflicting evidence has been reported in recent years on whether this reaction can occur in the absence of ADO. Here we sought to address whether physiological oxidative stress can interfere with ADO-catalysed N-terminal dioxygenation. Using a system to produce titratable intracellular levels of H2O2, we demonstrate that the stability of RGS4 and 5 is not affected by oxidative stress, whether ADO is present or not. However, cytotoxic levels of oxidative stress did induce an increase in RGS4/5 protein levels that occurred independently of the Cys N-degron pathway. This effect of tBHP was reduced by Fe2+ chelation and perturbations of lysosomal function, suggesting the possible involvement of ferroptosis. We conclude that N-terminal cysteine dependent proteolysis of RGS4/5 is not sensitive to physiological oxidative stress, but these proteins can be stabilised during the process of oxidative stress-induced cell death through an N-terminal cysteine independent mechanism.

cell biology↗

bioRxiv2023

Hif-2α programmes oxygen chemosensitivity in chromaffin cells

The study of transcription factors that determine specialised neuronal functions has provided invaluable insights into the physiology of the nervous system. Peripheral chemoreceptors are neurone-like electro-physiologically excitable cells that link the oxygen content of arterial blood to the neuronal control of breathing. In the adult, this oxygen chemosensitivity is exemplified by the Type I cells of the carotid body and recent work has revealed one isoform of the transcription factor HIF, HIF-2, to have a non-redundant role in the development and function of that organ. Here we show that the activation of HIF-2, including isolated overexpression alone, is sufficient to induce oxygen chemosensitivity in the otherwise unresponsive adult adrenal medulla. This phenotypic change in the adrenal medulla was associated with retention of extra-adrenal paraganglioma-like tissues that resemble the foetal organ of Zuckerkandl and also manifest oxygen chemosensitivity. Acquisition of chemosensitivity was associated with changes in the adrenal medullary expression of classes of genes that are ordinarily characteristic of the carotid body, including G-protein regulators and atypical subunits of mitochondrial cytochrome oxidase. Overall, the findings suggest that, at least in certain tissues, HIF-2 acts as a phenotypic driver for cells that display oxygen chemosensitivity, providing a route to mechanistic understanding.

developmental biology↗

bioRxiv2022

Hypoxia shapes the immune landscape in lung injury promoting inflammation persistence

Acute Respiratory Distress Syndrome (ARDS), an often-fatal complication of pulmonary or systemic inflammation, has no cure. Hypoxemia is a defining feature, yet its impact on inflammation is often neglected. Patients with ARDS are monocytopenic early in the onset of the disease. Endotoxin or Streptococcus pneumoniae acute lung injury (ALI) in the context of hypoxia replicates this finding, through hypoxia-driven suppression of type I interferon signalling. This results in failed lung monocyte-derived interstitial macrophages (IM) niche expansion and unchecked neutrophilic inflammation. Administration of colony stimulating factor 1 (CSF1) rescues the monocytopenia, alters the circulating classical monocyte phenotype in hypoxic endotoxin-driven ALI and enables lung IM population expansion, thus limiting lung injury in endotoxin- and virally-induced hypoxic ALI. Hypoxia directly alters immune dynamics to the detriment of the host and manipulation of this aberrant response offers new therapeutic strategies for ARDS.

cell biology↗