Biology subjects

Zamora, M.

Publications and source records attributed to Zamora, M..

13 recordsLinked to original sources

bioRxiv2026

Nanoparticle Albumin-Bound Paclitaxel Targets Pulmonary Neutrophils

Nanoparticle albumin-bound paclitaxel (Abraxane) was among the first clinically approved nanomedicines and is a first-line chemotherapeutic. It enhances therapeutic efficacy and reduces side effects of paclitaxel. Despite its extensive clinical use, mechanisms of Abraxane's therapeutic effects are the subject of ongoing study. This work posits a new mechanism for Abraxane's effects in lung cancers and metastasis. Tracing the albumin component of Abraxane with radioisotopes or fluorophores, we find that Abraxane homes to the lungs. Abraxane's lung tropism is elevated by inflammation and is eliminated in complement protein C3 knockout mice, showing that complement pathway drives the uptake. Flow cytometry and histology show that neutrophils are the dominant cell type taking up Abraxane in the lungs. We demonstrate Abraxane's tropism to pulmonary neutrophils in mice and in human donor lungs. We note previously undocumented side effects associated with Abraxane's lung tropism, including pro-thrombotic and pro-inflammatory responses in acute lung inflammation. We show that Abraxane's efficacy against lung metastases is affected when lung uptake is eliminated by C3 knockout. Our results provide insight into why Abraxane is effective in lung cancer and metastases. These findings may be used to improve outcomes in patients receiving Abraxane and help design next-generation cancer nanomedicines.

bioengineering↗

bioRxiv2025

A clinical grade neurostimulation implant for hierarchical control of physiological activity

Bioelectronic implants for neurostimulation aim to steer disordered neurophysiological processes back towards a healthy state. However, physiology is subject to biological rhythms, including the circadian rhythm and the sleep-wake cycle. These predictable rhythms affect disease symptomatology, biomarkers used in closed-loop therapies, and a physiological systems expected response to stimulation. Therefore, therapeutic devices should incorporate feedforward elements to align algorithm parameters with predictable changes in physiological state, as a parallel of physiological rheostatic control. Here we introduce the DyNeuMo-2c, the first clinical-grade implant capable of delivering closed-loop neurostimulation while flexibly changing its functional configuration according to time of day. The device can chronically measure brain activity and motion state to track potential biomarker patterns in natural, out-of-clinic settings, allowing identification and targeting of patient-specific chronotypes. The system implements a hierarchical control flow, with baseline therapy set by a circadian scheduler, and adaptive policies layered to take effect based on specific biomarkers indicating patient and disease state. Using a benchtop validation setup, we demonstrate that the system has the required capabilities for delivering time-contingent closed-loop therapy in two established clinical use cases: Parkinsons disease and epilepsy. Next, we deploy the system in vivo to deliver closed-loop deep brain stimulation in a healthy non-human primate model of vigilance, highlighting the importance of synchronisation between device operation and physiological state in various conditions (task performance, unconstrained behaviour, and sleep). Time-of-day-dependent adaptation of closed-loop stimulation enabled modulation of both vigilance and behaviour. Overall, the novel device architecture provides a proof-of-concept for delivering time-contingent therapy in chronic therapeutic settings where biological rhythms are of key importance.

neuroscience↗

bioRxiv2025

Prioritizing Combinational Drug Screening: A Ranking System for In Vitro Drug Combinations in Neurofibromatosis Type 1

Neurofibromatosis type 1 (NF1) is a genetic disorder characterized by benign tumors, including plexiform neurofibromas, which can be difficult to treat. Currently, only two FDA-approved therapies exist: selumetinib, approved for pediatric patients with inoperable tumors, and mirdametinib, approved for patients aged two and older with symptomatic peripheral neuropathy where surgical resection is not possible. These limited options highlight the urgent need for novel therapeutic strategies, including combination therapies and therapies applicable to adult populations. In this study, we introduce the Composite Matrix Reduction Score (CMRS), a novel algorithm designed to evaluate the in vitro efficacy of drug combinations for NF1-related plexiform neurofibromas. Using a high-throughput 6x6 combinatorial matrix, we screened three cell lines: ipnNF95.11c (NF1+/-, non-tumor reference), and two NF1-/- tumor lines: ipNF05.5mc and ipNF95.6. Cell viability responses to drug combinations were normalized to vehicle controls, and combination effects were compared to single-agent responses. Tumor-to-non-tumor response ratios were aggregated to generate a composite ranking for each drug pair. Our results show that certain drug combinations outperformed single agents in reducing tumor cell viability, consistent with findings in other cancers. A focused analysis on selumetinib combinations supported the CMRS algorithm and identified potential synergistic partners that may surpass a single-agent therapy, highlighting candidates for continued investigation. CMRS provides a scalable, standardized framework for prioritizing drug combinations in NF1 and potentially other cancers. By integrating multi-cell line analysis, this approach enhances the identification of promising therapeutic candidates and mechanisms of action for further preclinical development.

cancer biology↗

bioRxiv2025

Integrin α5β1 mediates the inhibitory effects of vasoinhibin on angiogenesis and vascular permeability

Vasoinhibin exerts potent inhibitory effects on angiogenesis and vascular permeability through a minimal three-amino acid sequence, the HGR motif. However, the nature of the vasoinhibin receptor has remained controversial. Here, we identify integrin 5{beta}1 as the endothelial cell-surface binding molecule mediating the actions of the HGR motif. Vasoinhibin binds to 5{beta}1 integrin through this motif, and silencing the integrin 5 subunit abolishes the vasoinhibin-mediated inhibition of endothelial cell proliferation, invasion, and permeability. Notably, the HGR motif activates integrin 5{beta}1, as reflected by an increase in endothelial cell adhesion to fibronectin, the canonical ligand of integrin 5{beta}1. These findings identify integrin 5{beta}1 as the molecular target of vasoinhibin mediating its antiangiogenic and anti-vasopermeability actions. Furthermore, a novel integrin activation mechanism leading to suppressed angiogenesis is unveiled, thereby challenging the conventional integrin inhibition approach as a therapeutic intervention.

cell biology↗

bioRxiv2024

The antiangiogenic peptide VIAN-c4551 inhibits lung melanoma metastasis in mice by reducing pulmonary vascular permeability

IntroductionCancer cells drive the increase in vascular permeability mediating tumor cell extravasation and metastatic seeding. VIAN-c4551, an antiangiogenic peptide analog of vasoinhibin, inhibits the growth and vascularization of melanoma tumors in mice. Because VIAN-c4551 is a potent inhibitor of vascular permeability, we evaluated whether its antitumor action extended to a reduction in metastasis generation. MethodsCirculating levels of vascular endothelial growth factor (VEGF), lung vascular permeability, melanoma cell extravasation, and melanoma pulmonary nodules were assessed in C57BL/6J mice intravenously inoculated with murine melanoma B16-F10 cells after acute treatment with VIAN-c4551. VEGF levels, transendothelial electrical resistance, and transendothelial migration in cocultures of B16-F10 cells and endothelial cell monolayers supported the findings. ResultsB16-F10 cells increased circulating VEGF levels and elevated lung vascular permeability 2 hours after inoculation. VIAN-c4551 prevented enhanced vascular permeability and reduced melanoma cell extravasation after 2 hours and the number and size of macroscopic and microscopic melanoma tumors in lungs after 17 days. In vitro, VIAN-c4551 suppressed the B16-F10 cell-induced and VEGF mediated increase in endothelial cell monolayer permeability and the transendothelial migration of B16-F10 cells. ConclusionsThese findings support the inhibition of distant vascular permeability for the prevention of tumor metastasis and unveil the anti-vascular permeability factor VIAN-c4551 as a potential therapeutic drug able to prevent metastasis generation by lowering the extravasation of melanoma cells.

cancer biology↗

bioRxiv2024

Vasoinhibin is Generated by the Renin-Angiotensin System

Vasoinhibin is a fragment of the hormone prolactin (PRL) that inhibits angiogenesis, vasopermeability, and vasodilation. Cathepsin D (CTSD) cleaves the N-teminal of PRL to generate vasoinhibin in the retina of neonate mice as revealed by the CTSD inhibitor, pepstatin A (PA). However, PA also inhibits renin. Because renin is expressed in the retina and the renin-angiotensin system (RAS) gives rise to peptides with positive and negative effects on blood vessel growth and function, we investigated whether renin cleaves PRL to vasoinhibin in the newborn mouse retina and in the circulation. Newborn mouse retinal extracts from wild-type and CTSD-null newborn mice cleaved PRL to a 14 kDa vasoinhibin and such cleavage was prevented by heat-inactivation, PA, and the selective renin inhibitor VTP-27999 suggesting the contribution of renin. In agreement, recombinant renin cleaved different species PRLs to the expected 14 kDa vasoinhibin, a mass consistent with a consensus renin cleavage site located at Leu124-Leu125 in rat and mouse PRLs and at Leu126-Leu127 in human, bovine, and ovine PRLs. Dehydration and rehydration (D/R) in rats increased the levels of renin and PRL in plasma. Further increase in PRL circulating levels by the dopamine D2 receptor blocker, sulpiride, enabled detection of 14 kDa vasoinhibin in D/R rats. Moreover, the incubation of PRL with plasma from D/R rats generated a 14 kDa vasoinhibin that was prevented by VTP-27999. These findings add renin to the list of PRL-cleaving proteases and introduce vasoinhibin as a RAS-mediated mechanism for regulating blood vessel growth and function.

physiology↗

bioRxiv2024

Topical Ophthalmic Administration of VIAN-c4551 Antiangiogenic Peptide for Diabetic Macular Edema: Preclinical Efficacy and Ocular Pharmacokinetics

VIAN-c4551 is a cyclic antiangiogenic peptide that stands as a potent and stable inhibitor of vascular endothelial cell growth factor (VEGF), the major vasopermeability and angiogenic factor in diabetic macular edema and diabetic retinopathy. Intravitreal injections of inhibitors of VEGF are a first-line therapy, but the invasiveness, risk, and low adherence of frequent intravitreal injections interfere with the needed long-term treatments and successful outcomes. Eye drops are non-invasive and favor compliance. Here, we evaluated the preclinical efficacy, permeability, and ocular pharmacokinetics of VIAN-c4551 delivered in eye drops. VIAN-c4551 demonstrated high potency (IC50 = 137 pM) to inhibit the permeability of human umbilical vein endothelial cell monolayers induced by VEGF. VIAN-c4551 eye drops potently (0.005% minimum effective dose) prevented the retinal vascular leakage induced by VEGF injected intravitreally for up to 24 hours and reversed the increase in retinal vascular permeability due to streptozotocin-induced diabetes in rats and mice. VIAN-c4551 exhibited high permeability across MDCK epithelium and, after a single topical ocular instillation in rabbits, reached the retina-choroid in micromolar concentrations several orders of magnitude above its IC50 (Cmax= 51 {micro}M at 6 hours) that lasted at least 24 hours. In conclusion, VIAN-c4551 eye drops reach the back of the eye at therapeutic concentrations, providing a potential, once-a-day, non-invasive intervention for preventing and reversing retinal vascular leakage in diabetic macular edema, diabetic retinopathy, and other vascular retinopathies and preserving sight.

pharmacology and toxicology↗

bioRxiv2023

The apoptotic, inflammatory, and fibrinolytic actions of vasoinhibin are in a motif different from its antiangiogenic HGR motif

Vasoinhibin is a proteolytic fragment of the hormone prolactin that inhibits blood vessel growth (angiogenesis) and permeability, stimulates the apoptosis and inflammation of endothelial cells and promotes fibrinolysis. The antiangiogenic and antivasopermeability properties of vasoinhibin were recently traced to the HGR motif located in residues 46 to 48, allowing the development of potent, orally active, HGR-containing vasoinhibin analogs for therapeutic use against angiogenesis-dependent diseases. However, whether the HGR motif is also responsible for the apoptotic, inflammatory, and fibrinolytic properties of vasoinhibin has not been addressed. Here, we report that HGR-containing analogs are devoid of these properties. Instead, the incubation of human umbilical vein endothelial cells with oligopeptides containing the sequence HNLSSEM, corresponding to residues 30 to 36 of vasoinhibin, induced apoptosis, the nuclear translocation of NF-{kappa}B, the expression of genes encoding leukocyte adhesion molecules (VCAM1 and ICAM1) and proinflammatory cytokines (IL1B, IL6, TNF), and the adhesion of peripheral blood leukocytes. Also, the intravenous or intra-articular injection of HNLSSEM-containing oligopeptides induced the expression of Vcam1, Icam1, Il1b, Il6, Tnf in the lung, liver, kidney, eye, and joints of mice and, like vasoinhibin, these oligopeptides promoted the lysis of plasma fibrin clots by binding to plasminogen activator inhibitor-1 (PAI-1). Moreover, the inhibition of PAI-1, urokinase plasminogen activator receptor, or NF-{kappa}B prevented the apoptotic and inflammatory actions. In conclusion, the functional properties of vasoinhibin are segregated into two different structural determinants. Because apoptotic, inflammatory, and fibrinolytic actions may be undesirable for antiangiogenic therapy, HGR-containing vasoinhibin analogs stand as selective and safe agents for targeting pathological angiogenesis.

cell biology↗

bioRxiv2023

Bioelectronic Zeitgebers: targeted neuromodulation to re-establish circadian rhythms.

Existing neurostimulation systems implanted for the treatment of neurodegenerative disorders generally deliver invariable therapy parameters, regardless of phase of the sleep/wake cycle. However, there is considerable evidence that brain activity in these conditions varies according to this cycle, with discrete patterns of dysfunction linked to loss of circadian rhythmicity, worse clinical outcomes and impaired patient quality of life. We present a targeted concept of circadian neuromodulation using a novel device platform. This system utilises stimulation of circuits important in sleep and wake regulation, delivering bioelectronic cues (Zeitgebers) aimed at entraining rhythms to more physiological patterns in a personalised and fully configurable manner. Preliminary evidence from its first use in a clinical trial setting, with brainstem arousal circuits as a surgical target, further supports its promising impact on sleep/wake pathology. Data included in this paper highlight its versatility and effectiveness on two different patient phenotypes. In addition to exploring acute and long-term electrophysiological and behavioural effects, we also discuss current caveats and future feature improvements of our proposed system, as well as its potential applicability in modifying disease progression in future therapies.

bioengineering↗

bioRxiv2023

The Design of Brainstem Interfaces: Characterisation of Physiological Artefacts and Implications for Closed-loop Algorithms

Surgical neuromodulation through implantable devices allows for stimulation delivery to subcortical regions, crucial for symptom control in many debilitating neurological conditions. Novel closed-loop algorithms deliver therapy tailor-made to endogenous physiological activity, however rely on precise sensing of signals such as subcortical oscillations. The frequency of such intrinsic activity can vary depending on subcortical target nucleus, while factors such as regional anatomy may also contribute to variability in sensing signals. While artefact parameters have been explored in more standard and commonly used targets (such as the basal ganglia, which are implanted in movement disorders), characterisation in novel candidate nuclei is still under investigation. One such important area is the brainstem, which contains nuclei crucial for arousal and autonomic regulation. The brainstem provides additional implantation targets for treatment indications in disorders of consciousness and sleep, yet poses distinct anatomical challenges compared to central subcortical targets. Here we investigate the region-specific artefacts encountered during activity and rest while streaming data from brainstem implants with a cranially-mounted device in two patients. Such artefacts result from this complex anatomical environment and its interactions with physiological parameters such as head movement and cardiac functions. The implications of the micromotion-induced artefacts, and potential mitigation, are then considered for future closed-loop stimulation methods.

bioengineering↗

bioRxiv2022

Reversal of lactate and PD-1-mediated macrophage immunosuppression controls growth of PTEN/p53-deficient prostate cancer

PTEN loss-of-function occurs in approximately 50% of mCRPC patients, and is associated with a poor prognosis, therapeutic outcomes and resistance to immune-checkpoint inhibitors. Recent clinical studies demonstrated that dual PI3K/AKT pathway inhibition and androgen axis blockade led to a modest improvement in progression-free survival of PTEN-deficient mCRPC patients, but the mechanistic basis for this limited efficacy is unknown. To elucidate potential resistance mechanism(s), we performed co-clinical trials in a prostate-specific PTEN/p53-deficient genetically-engineered mouse model, and discovered that the recruitment of PD-1-expressing tumor-associated macrophages (TAM) thwarts the phagocytosis-mediated anti-tumor efficacy of androgen deprivation therapy (ADT)/PI3K inhibitor (PI3Ki) combination. Strikingly, we observed a TAM-dependent [~]3-fold enhancement in the overall response rate with the addition of PD-1 antibody (aPD-1) to ADT/PI3Ki combination therapy. Mechanistically, decreased lactate production from PI3Ki-treated tumor cells suppressed histone lactylation (H3K18lac) within TAM, resulting in their phagocytic activation, which was augmented by concurrent ADT/aPD-1 treatment. Consistent with our murine observations, single cell RNA-sequencing analysis of human metastatic PC samples revealed a direct correlation between high glycolytic activity and phagocytosis suppression. Critically, feedback activation of Wnt/{beta}-catenin signaling observed in non-responder mice following ADT/PI3Ki/aPD-1 combination treatment, restored lactate-mediated H3K18lac and suppressed phagocytosis within macrophages. Altogether, these data suggest that reversal of lactate and PD-1-mediated TAM immunosuppression by PI3Ki and aPD-1, respectively, controls tumor growth in combination with ADT, and warrants further clinical investigation in PTEN/p53-deficient mCRPC patients. One Sentence SummaryInhibition of tumor-cell intrinsic lactate production suppresses PTEN/p53-deficient prostate cancer growth via macrophage activation/phagocytosis

cancer biology↗

bioRxiv2021

The spike protein of SARS-CoV-2 induces endothelial inflammation through integrin α5β1 and NF-κB

Vascular endothelial cells (EC) form a critical interface between blood and tissues that maintains whole-body homeostasis. In COVID-19, disruption of the EC barrier results in edema, vascular inflammation, and coagulation, the hallmarks of the severe disease. However, the mechanisms by which EC are dysregulated in COVID-19 are unclear. Here, we show that the spike protein of SARS-CoV-2 alone activates the EC inflammatory phenotype in a manner dependent on integrin 5{beta}1 signaling. Incubation of human umbilical vein EC with whole spike, its receptor-binding domain, or the integrin-binding tripeptide RGD induced the nuclear translocation of NF-{kappa}B and enhanced the expression of leukocyte adhesion molecules VCAM1 and ICAM1, the adhesion of peripheral blood leukocytes, and the permeability of the monolayer. Inhibitors of integrin 5{beta}1 activation prevented these effects. We suggest that the spike protein, through its RGD motif in the receptor-binding domain, binds to integrin 5{beta}1 in EC to activate Rho GTPases, eNOS pathways, and the NF-{kappa}B gene expression program responsible for vascular leakage and leukocyte infiltration, respectively. These findings uncover a new direct action of SARS-CoV-2 on EC dysfunction and introduce integrin 5{beta}1 as a promising target for treating vascular inflammation in COVID-19.

cell biology↗

bioRxiv2020

DyNeuMo Mk-1: A Fully-Implantable, Motion-Adaptive Neurostimulator with Configurable Response Algorithms

There is growing interest in using adaptive neuro-modulation to provide a more personalized therapy experience that might improve patient outcomes. Current implant technology, however, can be limited in its adaptive algorithm capability. To enable exploration of adaptive algorithms with chronic implants, we designed and validated the Picostim DyNeuMo Mk-1 (DyNeuMo Mk-1 for short), a fully-implantable, adaptive research stimulator that titrates stimulation based on circadian rhythms (e.g. sleep, wake) and the patients movement state (e.g. posture, activity, shock, free-fall). The design leverages off-the-shelf consumer technology that provides inertial sensing with low-power, high reliability, and relatively modest cost. The DyNeuMo Mk-1 system was designed, manufactured and verified using ISO 13485 design controls, including ISO 14971 risk management techniques to ensure patient safety, while enabling novel algorithms. The system was validated for an intended use case in movement disorders under an emergency-device authorization from the Medicines and Healthcare Products Regulatory Agency (MHRA). The algorithm configurability and expanded stimulation parameter space allows for a number of applications to be explored in both central and peripheral applications. Intended applications include adaptive stimulation for movement disorders, synchronizing stimulation with circadian patterns, and reacting to transient inertial events such as posture changes, general activity, and walking. With appropriate design controls in place, first-in-human research trials are now being prepared to explore the utility of automated motion-adaptive algorithms.

bioengineering↗