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Biology subjects

Pero, M. E.

Publications and source records attributed to Pero, M. E..

7 recordsLinked to original sources

Preventing neuropathy and improving anti-cancer chemotherapy with a carbazole-based compound

Advances in cancer treatment have led to a steady increase in the rate of disease remission. However, while many treatment-related adverse effects gradually resolve after therapy, chemotherapy-induced peripheral neuropathy (CIPN) often persists, with no means of prevention or direct treatment available. Herein, we present Carba1, a novel bi-functional carbazole that mitigates neuropathy through two distinct mechanisms. First, by interacting with tubulin, Carba1 reduces the required dose of taxanes, widely used chemotherapy drugs notorious for their toxic side effects, including CIPN. Second, Carba1 activates nicotinamide phosphoribosyltransferase (NAMPT), the rate-limiting enzyme in the NAD salvage pathway, triggering a metabolic rewiring that enhances the resilience of neurons and Schwann cells against chemotherapy-induced toxicity. We demonstrate the neuroprotective efficacy of Carba1 both in vitro, against neurotoxicity induced by paclitaxel (PTX), cisplatin, and bortezomib, and in vivo in a rat model of PTX-induced neuropathy. Importantly, we establish that Carba1 does not compromise the therapeutic efficacy of PTX nor promotes tumor growth. Comparative analyses of Carba1 derivatives further suggest the potential of designing compounds with either dual synergistic and neuroprotective activity or exclusive neuroprotective properties. Altogether, our findings position Carba1 as a promising therapeutic candidate for preventing CIPN, with the potential, if successfully translated to clinical settings, to improve both the quality of life and treatment outcome for cancer patients.

cancer biology↗

MFN2-dependent recruitment of ATAT1 coordinates mitochondria motility with alpha-tubulin acetylation and is disrupted in CMT2A

Acetylated microtubules play key roles in the regulation of mitochondria dynamics. It has however remained unknown if the machinery controlling mitochondria dynamics functionally interacts with the -tubulin acetylation cycle. Mitofusin-2 (MFN2), a large GTPase residing in the mitochondrial outer membrane and mutated in Charcot-Marie-Tooth type 2 disease (CMT2A), is a regulator of mitochondrial fusion, transport and tethering with the endoplasmic reticulum. The role of MFN2 in regulating mitochondrial transport has however remained elusive. Here we show that mitochondrial contacts with microtubules are sites of -tubulin acetylation, which occurs through the MFN2-mediated recruitment of -tubulin acetyltransferase 1 (ATAT1). We discover that this activity is critical for MFN2-dependent regulation of mitochondria transport, and that axonal degeneration caused by CMT2A MFN2 associated mutations, R94W and T105M, may depend on the inability to release ATAT1 at sites of mitochondrial contacts with microtubules. Our findings reveal a function for mitochondria in regulating acetylated -tubulin and suggest that disruption of the tubulin acetylation cycle play a pathogenic role in the onset of MFN2-dependent CMT2A. O_FIG O_LINKSMALLFIG WIDTH=193 HEIGHT=200 SRC="FIGDIR/small/532838v1_ufig1.gif" ALT="Figure 1"> View larger version (41K): org.highwire.dtl.DTLVardef@3db8eorg.highwire.dtl.DTLVardef@143821corg.highwire.dtl.DTLVardef@1132b13org.highwire.dtl.DTLVardef@1710383_HPS_FORMAT_FIGEXP M_FIG C_FIG HighlightsO_LIMitochondria contacts with MTs are hotspots of -tubulin acetylation through the recruitment of ATAT1 by MFN2 C_LIO_LIMutations in MFN2 associated with CMT2A disease lose this activity by sequestering ATAT1 C_LIO_LIDistal axonal degeneration caused by loss of MFN2 depends on acetylated tubulin-mediated mitochondria transport C_LI eTOCRecruitment of ATAT1 to mitochondria by MFN2 is critical for axonal viability through the regulation of mitochondria transport, and is disrupted in CMT2A

cell biology↗

Impaired α-tubulin re-tyrosination leads to synaptic dysfunction and is a feature of Alzheimer's disease

In neurons, dynamic microtubules play regulatory roles in neurotransmission and synaptic plasticity. While stable microtubules contain detyrosinated tubulin, dynamic microtubules are composed of tyrosinated tubulin, suggesting that the tubulin tyrosination/detyrosination (Tyr/deTyr) cycle modulates microtubule dynamics and synaptic function. In the Tyr/deTyr cycle, the C-terminal tyrosine of -tubulin is re-added by tubulin-tyrosine-ligase (TTL). Here we show that TTL+/- mice exhibit decreased tyrosinated microtubules, synaptic plasticity and memory deficits, and that reduced TTL expression is a feature of sporadic and familial Alzheimers disease (AD), with human APPV717I neurons having less dynamic microtubules. We find that spines visited by dynamic microtubules are more resistant to Amyloid{beta}1-42 and that TTL, by promoting microtubule entry into spines, prevents A{beta}1-42-induced spine pruning. Our results demonstrate that the Tyr/deTyr cycle regulates synaptic plasticity, is protective against spine injury, and that tubulin re-tyrosination is lost in AD, providing evidence that a defective Tyr/deTyr cycle may contribute to neurodegeneration.

neuroscience↗

Transthyretin promotes axon growth via regulation of microtubule dynamics and tubulin acetylation

Transthyretin (TTR), a plasma and cerebrospinal fluid protein, increases axon growth and organelle transport in sensory neurons. These TTR functions were suggested to underlie its activity in promoting nerve regeneration. While neurons extend their axons, the microtubule (MT) cytoskeleton is crucial for the segregation of functional compartments and axonal outgrowth. Herein, we investigated the hypothesis that TTR promotes axon elongation and regeneration by modulating MT dynamics. Indeed, we found that TTR KO mice have an intrinsic increase in dynamic MTs and reduced levels of acetylated -tubulin in uninjured peripheral axons, and fail to modulate microtubule dynamics in response to sciatic nerve injury. Importantly, restoring acetylated -tubulin levels of TTR KO DRG neurons using an HDAC6 inhibitor was sufficient to completely revert defective MT dynamics and neurite outgrowth. In summary, our results revealed a new role for TTR in the modulation of MT dynamics by regulating -tubulin acetylation and support that this activity underlies TTR neuritogenic function.

neuroscience↗

Integrins protect nociceptive neurons in models of paclitaxel-mediated peripheral sensory neuropathy

Chemotherapy induced peripheral neuropathy (CIPN) is a major side effect from cancer treatment with no known method for prevention or cure in clinics. CIPN primarily affects unmyelinated nociceptive sensory terminals. Despite the high prevalence of CIPN, molecular and cellular mechanisms that lead to CIPN are still poorly understood. Here, we used a genetically tractable Drosophila model and primary sensory neurons isolated from adult mouse to examine the mechanisms underlying CIPN and identify protective pathways. We found that chronic treatment of Drosophila larvae with paclitaxel caused sensory neuron degeneration, altered the terminal branching pattern of nociceptive neurons, and reduced thermal nociceptive responses. We found that nociceptive neuron-specific overexpression of integrins, which are known to support neuronal maintenance in several systems, conferred protection from paclitaxel-mediated cellular and behavioral phenotypes. Live imaging and superresolution approaches provide evidence that paclitaxel treatment causes cellular changes that are consistent with alterations in endosome-mediated trafficking of integrins. We used primary dorsal root ganglia neuron cultures to test conservation of integrin-mediated protection. We show that overexpression of a human integrin {beta} subunit 1 (ITGB1) also prevented degeneration following paclitaxel treatment. Altogether, our study supports conserved mechanisms of paclitaxel-induced perturbation of integrin trafficking and a therapeutic potential of restoring integrin levels to antagonize paclitaxel-mediated toxicity in sensory neurons.

neuroscience↗

Arfgef1 haploinsufficiency in mice alters neuronal endosome composition and decreases membrane surface postsynaptic GABAA receptors

ARFGEF1 encodes a guanine exchange factor involved in intracellular vesicle trafficking, and is a candidate gene for childhood genetic epilepsies. To model ARFGEF1 haploinsufficiency observed in a recent Lennox Gastaut Syndrome patient, we studied a frameshift mutation (Arfgef1fs) in mice. Arfgef1fs/+ pups exhibit signs of developmental delay, and Arfgef1fs/+ adults have a significantly decreased threshold to induced seizures but do not experience spontaneous seizures. Histologically, the Arfgef1fs/+ brain exhibits a disruption in the apical lining of the dentate gyrus and altered spine morphology of deep layer neurons. In primary hippocampal neuron culture, dendritic surface and synaptic but not total GABAA receptors (GABAAR) are reduced in Arfgef1fs/+ neurons with an accompanying decrease in GABAAR-containing recycling endosomes in cell body. Arfgef1fs/+ neurons also display differences in the relative ratio of Arf6+:Rab11+:TrfR+ recycling endosomes. Although the GABAAR-containing early endosomes in Arfgef1fs/+ neurons are comparable to wildtype, Arfgef1fs/+ neurons show an increase in GABAAR-containing lysosomes in dendrite and cell body. Together, the altered endosome composition and decreased neuronal surface GABAAR results suggests a mechanism whereby impaired neuronal inhibition leads to seizure susceptibility.\n\nHighlightsO_LIArfgef1fs/+ mice have lower seizure threshold but no spontaneous seizure.\nC_LIO_LIArfgef1fs/+ neurons show reduced dendritic surface GABAAR.\nC_LIO_LIArfgef1fs/+ neurons have decreased GABAAR-containing recycling endosome accompanied with an increase in GABAAR-containing lysosomes.\nC_LI

genetics↗

Pathogenic Role of Delta 2 Tubulin in Bortezomib Induced Peripheral Neuropathy

The pathogenesis of chemotherapy induced peripheral neuropathy (CIPN) is still poorly understood. Herein, we found that the CIPN-causing drug, bortezomib (Bort), induces delta 2 tubulin (D2) while affecting MT stability and dynamics in sensory neurons, and that accumulation of D2 is a hallmark of Bort-induced peripheral neuropathy in humans. Furthermore, while induction of D2 was sufficient to cause axonopathy and inhibit mitochondria motility, reducing D2 alleviated both axonal degeneration and loss of mitochondria motility promoted by Bort. Altogether, our data demonstrate that Bort, structurally unrelated to tubulin poisons, can affect the tubulin cytoskeleton in sensory neurons in vitro, in vivo and in humans, indicating that the pathogenic mechanisms of seemingly unrelated CIPN drugs may converge on tubulin damage. They further reveal a previously unrecognized pathogenic role for D2 in bortezomib-causing CIPN through its regulation of mitochondria dynamics.

neuroscience↗