Biology subjects

Rahmani, N.

Publications and source records attributed to Rahmani, N..

4 recordsLinked to original sources

bioRxiv2025

Cannabivarin and Tetrahydrocannabivarin Modulate Nociception via Vanilloid Channels and Cannabinoid-Like Receptors in Caenorhabditis elegans

Cannabis has attracted growing interest for its therapeutic potential, especially in pain management. This study explores the antinociceptive effects of two promising non-psychoactive cannabinoids, cannabivarin (CBV) and tetrahydrocannabivarin (THCV), using Caenorhabditis elegans (C. elegans), a nematode model that expresses homologs of mammalian cannabinoid and vanilloid receptors. Thermotaxis assays were employed to quantify the antinociceptive effects of CBV and THCV in C. elegans. Wild-type animals were exposed to increasing concentrations of each compound to establish dose-response relationships. To investigate potential molecular targets, additional experiments were performed using mutant strains deficient in vanilloid receptor homologs (OCR-2 and OSM-9) and cannabinoid receptor homologs (NPR-19 and NPR-32). Mass spectrometry-based proteomics combined with network biology analyses were used to identify the biological pathways associated with drug response. Results confirmed that both compounds elicit dose-dependent antinociceptive effects. Mutant analyses support the involvement of vanilloid and cannabinoid signaling pathways in mediating these responses. These findings highlight the potential of CBV and THCV as non-psychoactive analgesic agents and support further research into their mechanisms of action and translational relevance for mammalian pain management.

pharmacology and toxicology↗

bioRxiv2025

Amyloidogenic proteolysis of APP regulates glutamatergic presynaptic function

Disease causing mutations of Alzheimers disease (AD) point to dysregulations of APP proteolysis. During asymptomatic and early stages of AD, brain recordings revealed hyperexcitation reverting into over-inhibition as dementia progresses. Here, we show that endogenous APP and its proteolytic product APP-CTF{beta}, the precursors of A{beta}, accumulate preferentially at excitatory synapses. Using pharmacological treatments to modulate physiological concentrations of APP-CTF{beta} and A{beta}, we identify APP-CTF{beta} as a key regulator of glutamatergic synaptic transmission. Accumulation of APP-CTF{beta} increases the release probability of synaptic vesicles. Strikingly, monomeric A{beta} counteracts this APP-CTF{beta}-driven hyperexcitability. This suggests that therapeutic strategies clearing monomeric A{beta} could be detrimental during the early hyperexcitability phase of AD.

neuroscience↗

bioRxiv2025

TS2CG as a membrane builder

Molecular dynamics (MD) simulations excel at capturing biological processes at the molecular scale but rely on a well-defined initial structure. As MD simulations now extend to whole-cell-level modeling, new tools are needed to efficiently build initial structures. Here, we introduce TS2CG version 2, designed to construct coarse-grained membrane structures with any desired shape and lateral organization. This version enables precise placement of lipids and proteins based on curvature preference, facilitating the creation of large, near-equilibrium membranes. Additional features include controlled pore generation and the placement of specific lipids at membrane edges for stabilization. Moreover, a Python interface allows users to extend functionality while maintaining the high performance of the C++ core. To demonstrate its capabilities, we showcase challenging simulations, including a Mobius strip membrane, a vesicle with lipid domain as continental plates (Martini globe), and entire mitochondrial membranes exhibiting lipid heterogeneity due to curvature, along with a comprehensive set of tutorials.

biophysics↗

bioRxiv2021

An enhancer sequence in the intrinsically disordered region of the essential cell division protein FtsZ promotes conformation-guided substrate processing by ClpXP in Escherichia coli

The essential bacterial division protein in Escherichia coli, FtsZ, assembles into the FtsZ-ring at midcell and recruits other proteins to the division site to promote septation. A region of the FtsZ amino acid sequence that links the conserved polymerization domain to a C-terminal protein interaction site was predicted to be intrinsically disordered and has been implicated in modulating spacing and architectural arrangements of FtsZ filaments. While the majority of cell division proteins that directly bind to FtsZ engage either the polymerization domain or the C-terminal interaction site, ClpX, the recognition and unfolding component of the bacterial ClpXP proteasome, has a secondary interaction with the predicted intrinsically disordered region (IDR) of FtsZ when FtsZ is polymerized. Here, we use NMR spectroscopy and reconstituted degradation reactions in vitro to demonstrate that this linker region is indeed disordered in solution and, further, that amino acids in the IDR of FtsZ enhance the degradation by conformationally-guided interactions.

microbiology↗