Biology subjects

Lolicato, M.

Publications and source records attributed to Lolicato, M..

5 recordsLinked to original sources

bioRxiv2023

VDAC1 selective molecules promote patients-derived cancer organoids death through mitochondrial-dependent metabolic interference

In the continuous pursuit of advanced cancer therapeutics, our research unveils the potential to selectively target Voltage-Dependent Anion-selective Channel isoform 1 (VDAC1), a pivotal component in cellular metabolism and apoptosis. VDAC1s role in metabolic rewiring and its subsequent prominence in many cancer types offer a unique intervention point. The incorporation of a systematic, in silico to in vitro methodology identified novel VA (VDAC-Antagonist) molecules with the capability to selectively bind to VDAC1, displaying a substantial specificity towards cancer cells while sparing healthy ones. This research first led to the revelation of a specialized VDAC1 pocket, which accommodates the binding of these VA molecules, thereby instigating a selective displacement of NADH. The coenzyme is a critical metabolic substrate, and its displacement ensues in notable mitochondrial distress and a reduction in cell proliferation, specifically in cancer cells. Furthermore, meticulous analysis using organoids derived from intrahepatic cholangiocarcinoma patients (iCCA) demonstrated a dose-dependent reduction in cell viability upon treatment with VA molecules, correlating with the findings from commercial cell lines. Interestingly, VA molecules significantly reduced cell viability and demonstrated a lower impact on healthy cells than conventional treatments like gemcitabine. This differential impact is possibly due to the elevated expression of VDAC1 in various cancer cell lines, rendering them more susceptible to metabolic disruptions induced by VA molecules. This endeavor uncovers a multifaceted approach to cancer treatment, involving meticulous targeting of metabolic gatekeepers like VDAC1 using novel entities, thereby paving the way for developing more selective and refined cancer therapeutics. The identified VA molecules, albeit in the nascent stages, represent promising candidates for further optimization and development, potentially revolutionizing treatment modalities in cancer therapy through precise metabolic interventions.

biophysics↗

bioRxiv2023

Development of covalent chemogenetic K2P channel activators

K2P potassium channels regulate excitability by affecting cellular resting membrane potential in the brain, cardiovascular system, immune cells, and sensory organs. Despite their important roles in anesthesia, arrhythmia, pain, hypertension, sleep, and migraine, the ability to control K2P function remains limited. Here, we describe a chemogenetic strategy termed CATKLAMP (Covalent Activation of TREK family K+ channels to cLAmp Membrane Potential) that leverages the discovery of a site in the K2P modulator pocket that reacts with electrophile-bearing derivatives of a TREK subfamily small molecule activator, ML335, to activate the channel irreversibly. We show that the CATKLAMP strategy can be used to probe fundamental aspects of K2P function, as a switch to silence neuronal firing, and is applicable to all TREK subfamily members. Together, our findings exemplify a new means to alter K2P channel activity that should facilitate studies both molecular and systems level studies of K2P function and enable the search for new K2P modulators.

biophysics↗

bioRxiv2021

Quaternary structure independent folding of voltage-gated ion channel pore domain subunits

Every voltage-gated ion channel (VGIC) superfamily member has an ion conducting pore consisting of four pore domain (PD) subunits that are each built from a common plan comprising an antiparallel transmembrane helix pair, a short, obliquely positioned helix (the pore helix), and selectivity filter. The extent to which this structure, the VGIC-PD fold, relies on the extensive quaternary interactions observed in PD assemblies is unclear. Here, we present crystal structures of three bacterial voltage-gated sodium channel (BacNaO_SCPLOWVC_SCPLOW) pores that adopt a surprising set of non-canonical quaternary structures and yet maintain the native tertiary structure of the PD monomer. This context-independent structural robustness demonstrates that the VGIC-PD fold, the fundamental VGIC structural building block, can adopt its native-like tertiary fold independent of native quaternary interactions. In line with this observation, we find that the VGIC-PD fold is not only present throughout the VGIC superfamily and other channel classes but has homologs in diverse transmembrane and soluble proteins. Characterization of the structures of two synthetic Fabs (sFabs) that recognize the VGIC-PD fold shows that such sFabs can bind purified full-length channels and indicates that non-canonical quaternary PD assemblies can occur in the context of complete VGICs. Together, our data demonstrate that the VGIC-PD structure can fold independently of higher-order assembly interactions and suggest that full-length VGIC PDs can access previously unknown non-canonical quaternary states. These PD properties have deep implications for understanding how the complex quaternary architectures of VGIC superfamily members are achieved and point to possible evolutionary origins of this fundamental VGIC structural element.

biophysics↗

bioRxiv2020

K2P channel C-type gating involves asymmetric selectivity filter order-disorder transitions

K2P channels regulate nervous, cardiovascular, and immune system functions1,2 through the action of their selectivity filter (C-type) gate3-6. Although structural studies show K2P conformations that impact activity7-13, no selectivity filter conformational changes have been observed. Here, combining K2P2.1 (TREK-1) X-ray crystallography in different potassium concentrations, potassium anomalous scattering, molecular dynamics, and functional studies, we uncover the unprecedented, asymmetric, potassium-dependent conformational changes underlying K2P C-type gating. Low potassium concentrations evoke conformational changes in selectivity filter strand 1 (SF1), selectivity filter strand 2 (SF2), and the SF2-transmembrane helix 4 loop (SF2-M4 loop) that destroy the S1 and S2 ion binding sites and are suppressed by C-type gate activator ML335. Shortening the uniquely long SF2-M4 loop to match the canonical length found in other potassium channels or disrupting the conserved Glu234 hydrogen bond network supporting this loop blunts C-type gate response to various physical and chemical stimuli. Glu234 network destabilization also compromises ion selectivity, but can be reversed by channel activation, indicating that the ion binding site loss reduces selectivity similar to other channels14. Together, our data establish that C-type gating occurs through potassium-dependent order-disorder transitions in the selectivity filter and adjacent loops that respond to gating cues relayed through the SF2-M4 loop. These findings underscore the potential for targeting the SF2-M4 loop for the development of new, selective K2P channel modulators.

biophysics↗

bioRxiv2019

Polynuclear ruthenium amines inhibit K2P channels via a 'finger in the dam' mechanism

The trinuclear ruthenium amine Ruthenium Red (RuR) inhibits diverse ion channels including K2P potassium channels, TRPs, the mitochondrial calcium uniporter, CALHMs, ryanodine receptors, and Piezos. Despite this extraordinary array, there is very limited information for how RuR engages its targets. Here, using X-ray crystallographic and electrophysiological studies of an RuR-sensitive K2P, K2P2.1 (TREK-1) I110D, we show that RuR acts by binding an acidic residue pair comprising the Keystone inhibitor site under the K2P CAP domain archway above the channel pore. We further establish that Ru360, a dinuclear ruthenium amine not known to affect K2Ps, inhibits RuR-sensitive K2Ps using the same mechanism. Structural knowledge enabled a generalizable RuR super-responder design strategy for creating K2Ps having nanomolar sensitivity. Together, the data define a finger in the dam inhibition mechanism acting at a novel K2P inhibitor binding site. These findings highlight the polysite nature of K2P pharmacology and provide a new framework for K2P inhibitor development.

biophysics↗