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NAD + exerts its stabilizing effects on microtubules through SIRT3. (A) SIRT3 overexpression inhibits vinblastine-mediated microtubule depolymerization. To determine if a sirtuin mediates the effects of NAD + on microtubules, we tested each sirtuin for its effects on microtubule stability. In these experiments, MCF-7 cells were transfected with C-terminal GFP-tagged versions of SIRT1-7, and microtubule depolymerization was elicited by treatment of cells with vinblastine (VB; 100 nM) for 2 h. Microtubules were visualized by anti-Tyr-tubulin immunostaining (green). In control-transfected cells, minimal microtubule polymer mass remained after vinblastine treatment. However, cells expressing SIRT3-GFP exhibited marked protection of microtubules from vinblastine treatment. (Scale bar, 10 μm.) (B) Quantification of results in A. To quantify microtubule polymer mass in MCF-7 cells, polymerized microtubules were identified and binarized using the Tubeness plugin in Fiji, which identifies linear structures. The total area of the cell was calculated, and the graph represents the ratio of microtubule polymers to cell area, which we refer to as the polymerization index. We measured ∼100 cells from n = 3 replicates. Bar graph represents mean ± SEM; **P < 0.01 (one-way ANOVA with Tukey's post hoc test). (C) SIRT3 is necessary for the effects of NAD + on microtubule depolymerization. To determine if the effects of NAD + on microtubule stability are mediated through SIRT3, we monitored the effects of SIRT3 knockdown on NAD +-induced stabilization of microtubules. MCF-7 cells were treated with 100 nM vinblastine for 2 h, which results in both loss of the microtubule cytoskeleton and subsequent cell shrinkage. Microtubules were visualized by anti-Tyr-tubulin immunostaining (green). Treatment of these cells with 1 mM NAD + prevents the loss of the microtubule cytoskeleton and plasma membrane collapse. However, this effect of NAD + is lost in cells expressing either of two SIRT3specific shRNA. These cells also display more membrane collapse than control cells, suggesting that the loss of SIRT3 may make the cells more sensitive to vinblastine. These data indicate that SIRT3 is required for the protective effects of NAD + on the microtubule cytoskeleton. (Scale bar, 10 μm.) (D) Quantification of results in C. Quantification was performed as described in B. We measured ∼100 cells from n = 3 replicates. Bar graph represents mean ± SEM; **P < 0.01, ***P < 0.001 (one-way ANOVA with Tukey's post hoc test).
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Nicotinamide adenine dinucleotide (NAD ⁺ ) is an endogenous small molecule that has effects on diverse processes, including obesity, lifespan, and cancer. A major goal is to identify the NAD ⁺ -regulated cellular pathways that may mediate these effects. In this study, we demonstrate that NAD ⁺ regulates the microtubule cytoskeleton. We...
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Atherosclerosis is initiated by endothelial cell dysfunction and vascular inflammation under the condition of hyperlipidemia. Sirtuin 3 (SIRT3) is a nicotinamide adenine dinucleotide (NAD+)-dependent mitochondrial deacetylase, which plays a key role in maintaining normal mitochondrial function. The present study tested whether endothelial-selective...
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... These large datasets increase the sensitivity of our measurements, allowing us to detect minimal yet significant changes in MT dynamic signatures. Our computational approach has revealed novel organizational and regulatory patterns in MT homeostasis, initially in renal cell carcinoma 5 , and has begun to impact studies on a wide range of topics in cell and cancer biology [43][44][45][46][47][48][49][50][51][52][53][54][55] . ...
... We can now start identifying the proteins/pathways that regulate them and investigate their relative expression in patient-derived PCa organoids 56 , as cultures with high clinical relevance. In addition, we recently published our computational results on the analysis of the effects of one of the components of the organoid media, Nicotinamide, on MT dynamics 47 . ...
(See also the 8 PDF files appended below) The treatment of prostate cancer (PCa) has been impeded by the lack of clinically relevant disease models. There are only three PCa cell lines as available models of this heterogeneous disease out of the over 1,000 publicly available cancer cell lines; patient-derived
xenografts (PDX) have proven rarely possible to establish thus far. My previous work in PCa cell lines has demonstrated that we can associate the alterations in a particular parameter of microtubule (MT) dynamics to taxane resistance in ERG overexpressing cells. MT regulating genes such as chTOG, CLIP170, MAP4, MCAK, TPX2 and Op18 to name a few are implicated in the process of conferring drug resistance and susceptibility. Because these genes are also involved in the regulation of MT dynamics, my central hypothesis is that computational analysis of MT dynamics (MT signature) can serve as a real-time readout of cell susceptibility to drug action, which will allow to discover mechanisms of resistance. Therefore, to test my hypotheses in patient-derived cells, I propose to perform two specific aims in patient-derived PCa organoids: Specific Aim 1: Define and validate cancer-specific MT dynamics signatures of MT-targeting agents (MTA) resistance. I will image and measure endogenous and drug-induced signatures (consisting of 12 descriptive parameters) of MT dynamics alterations in patient-
derived cancer organoids using ClusterTrack. For each organoid type, I will measure populations of cells before and after treatment with MTAs, and will perform statistical analysis. I will use, as a
starting point, samples with known patient treatment outcome for specific MTAs (Docetaxel, Cabazitaxel, Eribulin, etc.), which will allow me to validate the MT signatures and classify them into
sensitive and resistant groups using clustering. Specific Aim 2: Define cancer-specific molecular mechanisms of MTA resistance to elucidate targeting strategies. I will extract RNA and will perform differential expression analysis of MT regulators in patient-derived cancer organoids as well as pathway analysis using iPAGE. I will correlate the RNA-seq MT signatures to the validated MT dynamics signatures obtained in Aim 1 using pattern matching. Correlated signatures will contain multiple up- or down-regulated MT regulator genes. I will test the proteins in these lists as candidates for personalized targets in knockdown and overexpression experiments. This approach could identify novel candidates for effective targeted therapies in metastatic disease within the MT-interacting transcriptome. I will further test these novel organoids into PDX models of PCa to confirm sensitization and therapeutic susceptibility in vivo. Further validation, of both prognostic and predictive markers, will be done by comparing ex vivo tumor growth kinetics and treatment predictions to outcomes of patients with similar genetic profiles, after drug treatment, enrolled in clinical trials. See: github.com/amatov/SegmentationBiomarkerCTC,
github.com/amatov/AntibodyTextureMorphology,
github.com/amatov/DataSetTracker
... These large datasets increase the sensitivity of the assay, allowing us to detect very small yet significant changes in MT dynamic signatures. Our computational approach has revealed novel organizational and regulatory patterns in MT homeostasis (initially in renal cell carcinoma 40 ) and has begun to impact studies on a wide range of topics in cell and cancer biology [41][42][43][44][45][46][47][48][49][50][51][52][53] . Our main objective in this proposal is to elucidate the various mechanisms of resistance by (i) classifying these signatures based on patient treatment outcome to investigate individual mechanisms of resistance to MT chemotherapy. ...
... It is conceivable that PCa which is different histologically would require different concentration of Y-27632 ROCK inhibitor; we will test this and will continue to systematically explore media compositions. We recently published our computational results on the analysis of the effects of another component of the organoid media, Nicotinamide, on MT dynamics 45 . There are two types of prostate organoids in our nomenclature: PR1-7 (primary) and PCa1 (metastatic). ...
(See also the 7 PDF files appended below) In the summer of 2007, ClusterTrack software, an approach that I conceived based on a hypothesis I formulated in 2005, allowed for the first time comprehensive measurements of microtubule behavior, encompassing all cellular areas, including the cell body, where the density of the cytoskeleton is high. Additionally, the ClusterTrack algorithm allowed for the characterization of the different stages of microtubule depolymerization, a process that cannot be visualized using existing molecular markers. Using this software, I
directly measured two parameters of microtubule dynamics and computationally inferred another ten parameters to evaluate a microtubule dynamics signature. This computational approach could evaluate and compare the effects of both established and new microtubule targeting agents on microtubule dynamics. In the
long run, dissecting the mechanisms of microtubule organization using this computing tool will allow better drugs to be designed by exploiting cancer-specific aberrations and aid in the characterization of new therapies that combine cytotoxic chemotherapy with small molecules to eliminate residual disease and impede relapse. Every aspect of tubulin dynamicity in living cells is controlled by multiple genes, whose up- or down-regulation is linked to resistance to therapy. About 70 microtubule-associated proteins and 80 proteins within the kinetochore complex can be targeted in RNA therapy. Microtubule regulators, GKS3β, TPX2, chTOG, KIF2C, MAP2, CLIP170, etc., are implicated in conferring drug resistance and pathogenesis. The expression levels of these genes can serve as a readout of susceptibility to drug action and as personalized targets. RNA therapy can (i) sensitize tumors to existing regimens or (ii) explore novel targets within the microtubule transcriptome. See:
github.com/amatov/InstantaneousFlowTracker, github.com/amatov/ClusterTrackTubuline,
github.com/amatov/DyneinFunctionAnalysis,
github.com/amatov/SegmentationBiomarkerCTC,
github.com/amatov/AutomatedBlotQuantification, github.com/amatov/DataSetTracker
... These large datasets increase the sensitivity of the assay, allowing to detect very small yet significant changes in MT signatures. My computational approach has revealed novel organizational and regulatory patterns in MT homeostasis (initially in renal cell carcinoma 3 ) and has begun to impact studies on a wide range of topics in cell and cancer biology 1,[42][43][44][45][46][47][48][49][50][51][52][53] . Of all solid tumors, BC is the disease with the highest number of MTAs approved, consisting of seven stabilizing and destabilizing MTAs, highlighting that MT targeting is impactful and yet, suggesting there is variability in patient response. ...
(See also the 8 PDF files appended below) This work is based on a hypothesis I formulated in 2006 pertaining to targeting particular aspects of microtubule dynamics for cancer treatment. Thereafter, my goal was to investigate breast cancer-specific aberrations at the cellular level. The microtubules are essential polymer filaments composed of tubulin subunits that organize and rearrange the interior of the cell. They play indispensable roles in several cellular processes such as migration, mitosis, and internal transport processes critically involved in cancer metastasis and proliferation. The microtubules are structurally stiff but dynamic. Their tendency to rapidly extend and retract in a stochastic way is termed dynamic instability of microtubule plus end tips. This dynamicity allows a cell to utilize microtubules in diverse functional contexts, one of which is mitosis. Microtubule rearrangement and cytoskeletal reorganization allow cells to assemble mitotic spindles. Within the spindles, the microtubules undergo a process termed treadmilling during which their plus ends are located in proximity to the chromosomes at the metaphase plate, where microtubules add dimers or polymerize, while their minus ends are located outward toward the two poles, from where the microtubules remove dimers or depolymerize at similar rates. These microtubule-based structures align duplicated chromosomes near the cell center and ultimately segregate the copies into each of the daughter cells. In interphase, microtubules are the freeways of the cellular transport infrastructure. Failure to maintain the appropriate microtubule cytoskeletal network during interphase or spindles with normal size and regulation during mitosis are hallmarks of disease. Further, the signaling molecules that interact with microtubules, as well as the multiple effects on signaling pathways that destabilize or hyper-stabilize microtubules, indicate that microtubules are likely to be critical to the spatial organization of signal transduction. How players in these pathways are positioned spatially and how signals travel within the intracellular environment from the cell surface to the nucleus or other cytoplasmic targets is poorly understood. The microtubules are also affected by signaling pathways, which contributes to the transmission of signals to downstream targets. The microtubule cytoskeleton is often targeted during treatment of metastatic solid tumors and breast cancer in particular, and the microtubules are one of the most validated targets in oncology due to the clinical efficacy of taxanes, vinca alkaloids and other tubulin inhibitors (e.g., epothilones, eribulin) in a wide range of degenerative diseases. Some microtubule-targeting agents bind to individual tubulin dimers and block tubulin polymerization (microtubule-destabilizing agents); others bind to the lattice of microtubules and inhibit microtubule ability to depolymerize (microtubule-stabilizing agents). For some cancers, several chemical compounds that disrupt the homeostasis of the microtubule cytoskeleton are used clinically, suggesting that targeting tubulin might be impactful, yet, there is large variability in patient response. Despite improvements in the diagnosis and therapy of many types of breast cancer, many aggressive forms, such as receptor triple-negative cancers, are associated with the worst patient outcomes; though initially effective in reducing tumor burden for some patients, acquired resistance to cytotoxic chemotherapy is almost universal, and there is no rationale for identifying intrinsically drug-resistant and drug-sensitive patient populations before initiating therapy. I performed high-resolution live-cell imaging of 12 cell lines with labeled microtubules. During cell division, the receptor triple-negative MDA-MB-231 mitotic spindles were the largest. They exhibited rapid lateral twisting during metaphase (see videos with examples of rotating spindles at vimeo.com/382125072/bce76f2ef0 and vimeo.com/382256739/ccd8ab1b63), which remained unaffected by knockdown of the oncogene Myc and treatment with inhibitors of the serine/threonine-protein kinase B-Raf and the epidermal growth factor receptor, alone or in any combination. The MDA-MB-231 cells are the most aggressive and rapidly form metastatic tumors in xenograft transplant models, and exhibited very high proliferation rates when I plated them as three-dimensional cultures in Matrigel. Quantitative image analysis of microtubules in six breast cancer cell lines (MDA-MB-231, LY2, ZR75B, HCC-1143, HCC-1428, HCC-3153) demonstrated that the rotational spindle rocking of MDA-MB-231 cells during metaphase appears coupled with a significant increase in microtubule polymerization rates during interphase, which likely shortens interphase and accelerates cell cycle progression and mitotic entry. Unlike the uniform treadmilling rates in kinetochore microtubules during metaphase I measured across cell lines, the alterations in interphase microtubule dynamics together with the abnormal mitotic spindle oscillations may represent a therapeutically targetable disrupted mechanism of spindle positioning in receptor triple-negative breast cancer cells leading to tumor aggressiveness. See:
github.com/amatov/InstantaneousFlowTracker, github.com/amatov/ClusterTrackTubuline,
github.com/amatov/DyneinFunctionAnalysis,
github.com/amatov/SegmentationBiomarkerCTC,
github.com/amatov/AutomatedBlotQuantification, github.com/amatov/DataSetTracker
... When NMNAT2, a ratelimiting enzyme in NAD+ production was diminished, abnormal spindle assembly increased (Wu et al., 2019). Also, NAD+ and SIRT3, a mitochondrial NAD+ dependent sirtuin, have been shown to control microtubule dynamics and reduce susceptibility to antimicrotubule agents such as vinblastine and colchicine (Harkcom et al., 2014). Additionally, SIRT4, another mitochondrial NAD+ dependent sirtuin, acts as a novel centrosomal/ microtubule-associated protein in the regulation of cell cycle progression (Bergmann et al., 2020). ...
Background:
Nicotinamide adenine dinucleotide (NAD+) depletion is associated with numerous diseases in humans. Recently it was revealed that genetic blockage of the NAD+ synthesis pathway in humans causes birth defects in multiple organ systems and miscarriage. Additionally, mice with NAD+ deficiency created through dietary restriction of tryptophan and vitamin B3 were shown to have congenital anomalies affecting virtually every organ system along with miscarriage. Perturbations in NAD+/NADH affect mechanisms of teratogenesis presented by Wilson and others, including genetic alterations, altered energy sources, and lack of precursors and substrates needed for biosynthesis.
Methods:
Medical literature was evaluated to demonstrate how perturbations in NAD+/NADH affect mechanisms of teratogenesis. In addition, literature describing several different teratogens of various types (infectious, physical, maternal health factors, drugs) was reviewed showing the impact of these teratogens on NAD+ and NAD+/NADH ratios.
Result:
Many teratogens affect NAD+ by altering its metabolism, decreasing its intracellular availability, or decreasing its production, which in turn is a plausible mechanism for the creation of birth defects.
Conclusion:
Looking at teratogens through the lens of their impact on NAD+ could provide valuable insight into the mechanism by which some teratogens cause birth defects and miscarriage.
... A previous study found that the acetylation of microtubule α-tubulin is a necessary step for NLRP3 inflammasome activation (41) (Fig. 2). Moreover, NAD + is an endogenous small molecule that regulates the microtubules (122). NAD + caused by reduced ATP production moves mitochondria through microtubules, therefore promotes the assembly of NLRP3 inflammasome (41). ...
Post‑ischemic neuroinflammation induced by the innate local immune response is a major pathophysiological feature of cerebral ischemic stroke, which remains the leading cause of mortality and disability worldwide. NLR family pyrin domain containing (NLRP)3 inflammasome crucially mediates post‑ischemic inflammatory responses via its priming, activation and interleukin‑1β release during hypoxic‑ischemic brain damage. Mitochondrial dysfunctions are among the main hallmarks of several brain diseases, including ischemic stroke. In the present review, focus was addressed on the role of mitochondria in cerebral ischemic stroke while keeping NLRP3 inflammasome as a link. Under ischemia and hypoxia, mitochondria are capable of controlling NLRP3 inflammasome‑mediated neuroinflammation through mitochondrial released contents, mitochondrial localization and mitochondrial related proteins. Thus, inflammasome and mitochondria may be attractive targets to treat ischemic stroke as well as the several drugs that target the process of mitochondrial function to treat cerebral ischemic stroke. At present, certain drugs have already been studied in clinical trials.
... Hence, our results indicated that α-Ac-Tub restored axonal transport of mitochondria and energy failure after ICH. These results were consistent with previous findings, which demonstrated that restoring cellular energetics prevented microtubule disassembly and axonal degeneration and promoted axonal regeneration (Han et al., 2020;Harkcom et al., 2014;Park et al., 2013). ...
... Recent studies demonstrated that energy failure occurred within 24 h after axotomy and triggered microtubule disassembly and axonal degeneration (Harkcom et al., 2014;Ruschel et al., 2015). Similarly, live imaging results revealed that mPTP was immediately activated in dendrites after stroke, which led to mitochondrial transmembrane potential collapse, Ca 2+ overload, and energy failure (Liu & Murphy, 2009). ...
Injury to long axonal projections is a central pathological feature at the early phase of intracerebral hemorrhage (ICH). It has been reported to contribute to persistent functional disability following ICH. However, the molecular mechanisms that drive axonal degeneration remain unclear. Autologous blood was injected into the striatum to mimic the pathology of ICH. Observed significant swollen axons with characteristic retraction bulbs were found around the striatal hematoma at 24 h after ICH. Electronic microscopic examination revealed highly disorganized microtubule and swollen mi-tochondria in the retraction bulbs. MEC17 is a specific α-tubulin acetyltransferase, ablation of acetylated α-tubulin in MEC17 −/− mice aggravated axonal injury, axonal transport mitochondria dysfunction, and motor dysfunction. In contrast, treatment with tubastatin A (TubA), which promotes microtubule acetylation, significantly alleviated axonal injury and protected the integrity of the corticospinal tract and fine motor function after ICH. Moreover, results showed that 41% mitochondria were preferentially bundled to the acetylated α-tubulin in identifiable axons and dendrites in primary neurons. This impaired axonal transport of mitochondria in primary neurons of MEC17 −/− mice. Given that opening of mitochondrial permeability transition pore (mPTP) induces mitochondrial dysfunction and impairs ATP supply thereby promoting axonal injury, we enhanced the availability of acetylated α-tubulin using TubA and inhibited mPTP opening with cyclosporin A. The results indicated that this combined treatment synergistically protected corticospinal tract integrity and promoted fine motor control recovery. These findings reveal key intracellular mechanisms that drive
... Therefore, we asked whether CD38-cADPR signaling stimulated ryanodine receptors in our astrocyte mitochondrial release model. Based on previous studies [44][45][46][47], NAD (5 mM) was added to rat cortical astrocytes to stimulate CD38 pathway. Immunocytochemistry showed that an hour after NAD treatment in astrocytes, the braintype ryanodine receptor 3 (RyR3) appeared to be coexpressed with the ER; no co-localization was detected with the Golgi (Fig. 1a). ...
... Second, physiological concentrations of NAD + and NADH in vivo may be in the micromolar range, but our study used 5 mM of NAD to stimulate cultured astrocytes in vitro. It has been reported that the millimolar range of NAD was sufficient for signaling experiments in vitro [44,45]. Moreover, NAD has a short half-life of about 1 h [46]. ...
Mitochondria can be released by astrocytes as part of a help-me signaling process in stroke. In this study, we investigated the molecular mechanisms that underlie mitochondria secretion, redox status, and functional regulation in the extracellular environment. Exposure of rat primary astrocytes to NAD or cADPR elicited an increase in mitochondrial calcium through ryanodine receptor (RyR) in the endoplasmic reticulum (ER). Importantly, CD38 stimulation with NAD accelerated ATP production along with increasing glutathione reductase (GR) and dipicolinic acid (DPA) in intracellular mitochondria. When RyR was blocked by Dantrolene, all effects were clearly diminished. Mitochondrial functional assay showed that these activated mitochondria appeared to be resistant to H2O2 exposure and sustained mitochondrial membrane potential, while inhibition of RyR resulted in disrupted membrane potential under oxidative stress. Finally, a gain- or loss-of-function assay demonstrated that treatment with DPA in control mitochondria preserved GR contents and increased mitochondrial membrane potential, whereas inhibiting GR with carmustine decreased membrane potentials in extracellular mitochondria released from astrocytes. Collectively, these data suggest that ER-mitochondrial interaction mediated by CD38 stimulation may support mitochondrial energy production and redox homeostasis during the mode of mitochondrial transfer from astrocytes.
... Hence, our results indicated that α-Ac-Tub restored axonal transport of mitochondria and energy failure after ICH. These results were consistent with previous findings, which demonstrated that restoring cellular energetics prevented microtubule disassembly and axonal degeneration and promoted axonal regeneration (Han et al., 2020;Harkcom et al., 2014;Park et al., 2013). ...
... Recent studies demonstrated that energy failure occurred within 24 h after axotomy and triggered microtubule disassembly and axonal degeneration (Harkcom et al., 2014;Ruschel et al., 2015). Similarly, live imaging results revealed that mPTP was immediately activated in dendrites after stroke, which led to mitochondrial transmembrane potential collapse, Ca 2+ overload, and energy failure (Liu & Murphy, 2009). ...
Injury to long axonal projections is a central pathological feature at the early phase of intracerebral hemorrhage (ICH). It has been reported to contribute to persistent functional disability following ICH. However, the molecular mechanisms that drive axonal degeneration remain unclear. Autologous blood was injected into the striatum to mimic the pathology of ICH. Observed significant swollen axons with characteristic retraction bulbs were found around the striatal hematoma at 24 h after ICH. Electronic microscopic examination revealed highly disorganized microtubule and swollen mitochondria in the retraction bulbs. MEC17 is a specific α‐tubulin acetyltransferase, ablation of acetylated α‐tubulin in MEC17−/− mice aggravated axonal injury, axonal transport mitochondria dysfunction, and motor dysfunction. In contrast, treatment with tubastatin A (TubA), which promotes microtubule acetylation, significantly alleviated axonal injury and protected the integrity of the corticospinal tract and fine motor function after ICH. Moreover, results showed that 41% mitochondria were preferentially bundled to the acetylated α‐tubulin in identifiable axons and dendrites in primary neurons. This impaired axonal transport of mitochondria in primary neurons of MEC17−/− mice. Given that opening of mitochondrial permeability transition pore (mPTP) induces mitochondrial dysfunction and impairs ATP supply thereby promoting axonal injury, we enhanced the availability of acetylated α‐tubulin using TubA and inhibited mPTP opening with cyclosporin A. The results indicated that this combined treatment synergistically protected corticospinal tract integrity and promoted fine motor control recovery. These findings reveal key intracellular mechanisms that drive axonal degeneration after ICH and highlight the need to target multiple factors and respective regulatory mechanisms as an effective approach to prevent axonal degeneration and motor dysfunction after ICH.
image
... Furthermore, NAD + also plays a role in controlling the actin cytoskeleton (Venter et al. 2014). However, it is unclear how BtpA depletion of NAD + would help to stabilize microtubules, a proposed role for this effector based on transfection experiments (Felix et al. 2014), given that microtubule depolymerization is blocked by increasing intracellular NAD + levels (Harkcom et al. 2014). ...
Nicotinamide adenine dinucleotide (NAD+) is a major cofactor in redox reactions in all lifeforms. A stable level of NAD+ is vital to ensure cellular homeostasis. Some pathogens can modulate NAD+ metabolism to their advantage and even utilize or cleave NAD+ from the host using specialized effectors known as ADP-ribosyltransferase toxins and NADases, leading to energy store depletion, immune evasion, or even cell death. This review explores recent advances in the field of bacterial NAD+-targeting toxins, highlighting the relevance of NAD+ modulation as an emerging pathogenesis strategy. In addition, we discuss the role of specific NAD+-targeting toxins in niche colonization and bacterial lifestyle as components of Toxin/Antitoxin systems and key players in inter-bacterial competition. Understanding the mechanisms of toxicity, regulation, and secretion of these toxins will provide interesting leads in the search for new antimicrobial treatments in the fight against infectious diseases.
... MT hyperstabilization plays a direct role in paclitaxel neurotoxicity (10), and a single nucleotide polymorphism in TUBB2a, a gene encoding a tubulin isoform, is associated with an enhanced risk of CIPN (11). Moreover, MT dynamics and stability are influenced by nicotinamide adenine dinucleotide (NAD+) levels through sirtuin modulation (12), suggesting a tubulin-mediated mechanism also for the NAD+-consuming activity of Sterile Alpha and Tir Motifs-containing protein 1 (SARM1) in driving axonal degeneration in CIPN models (13). ...
... Further work is necessary to provide insight into this regulation and the cross-talk between D2 and other tubulin PTMs, such as polyglutamylation and acetylation in the control of mitochondria energetics and dynamics. It will be equally crucial to investigate whether D2 accumulation affects responses to pro-survival and pro-death signals that could play a role in CIPN axon degeneration, including regulation of TRPV and Ca 2+ channels (12,13,21,23,61,62). ...
