Biology subjects

Lillo, M.

Publications and source records attributed to Lillo, M..

4 recordsLinked to original sources

bioRxiv2024

Soluble guanylyl cyclase, the NO-receptor, regulates endothelium-dependent vascular relaxation via its transnitrosation activity.

We previously demonstrated that the NO-receptor soluble guanylyl cyclase (GC1) has the ability to transnitrosate other proteins in a reaction that involves, in some cases, oxidized Thioredoxin 1 (oTrx1). This transnitrosation cascade was established in vitro and we identified by mass spectrometry and mutational analysis Cys 610 (C610) of GC1 -subunit as a major donor of S-nitrosothiols (SNO). To assay the relevance of GC1 transnitrosation under physiological conditions and in oxidative pathologies, we studied a knock-in mouse in which C610 was replaced with a serine (KI C610S) under basal or angiotensin II (Ang II)-treated conditions. Despite similar GC1 expression and NO-stimulated cGMP-forming activity, the Ang II-treated KI mice displayed exacerbated oxidative pathologies including higher mean arterial pressure and more severe cardiac dysfunctions compared to the Ang II-treated WT. These phenotypes were associated with a drastic decrease in global S-nitrosation and in levels of SNO-Trx1 and SNO-RhoA in the KI mice. To investigate the mechanism underlying the dysregulation of blood pressure despite an intact NO-cGMP axis, pressure myography and in vivo intravital microscopy were conducted to analyze the vascular resistance tone. Both approaches indicated that, even in the absence of oxidative stress, the single mutation C610S led to a significant deficiency in acetylcholine-induced vasorelaxation while smooth muscle relaxation in response to NO remained unchanged. These findings indicate that the C610S mutation uncoupled the two NO signaling pathways involved in the endothelium and smooth muscle vasorelaxation and suggest that GC1-dependent S-nitrosation is a key player in endothelium-derived hyperpolarization.

biochemistry↗

bioRxiv2022

Gender imbalances in citation rates are mediated by field specific author gender distributions

Gender biases are well documented in science and typically favor male scientists. In this context, a particularly pervasive gender bias is undercitation of publications authored by women, resulting in profound negative effects on academic visibility and career advancement. This bias has been well documented in fields where author gender distributions are strongly skewed towards men (e.g., astronomy, physics, neuroscience). By investigating citation practices in a field that has traditionally been more accessible to female scientists (Speech and Language Pathology, SLP), we demonstrate that gendered citation practices are mediated by author gender distribution, rather than being a universal pattern. Specifically, our results revealed a citation pattern in SLP that (a) overall tends to favor female authors, (b) persists after controlling for potential confounding factors and, (c) is particularly strong when female authors are citing publications involving female first and senior author teams. This research also implies that the implementation of effective measures to increase the number and influence of underrepresented individuals in specific fields of science may be suitable to mitigate downstream disadvantages for career advancement of either sex.

scientific communication and education↗

bioRxiv2022

Microtubule-Connexin-43 regulation suppresses arrhythmias and fibrosis in Duchenne muscular dystrophy mice.

Dilated cardiomyopathy is the leading cause of death in Duchenne muscular dystrophy (DMD) patients due to advancements in skeletal muscle therapies yet limited presence of cardiac treatments. The phosphorylation status of gap junction protein Connexin-43 (Cx43) drives Cx43 remodeling and the development of arrhythmias and fibrosis. Based on evidence that Colchicine drug treatment improves Cx43 phosphorylation and remodeling, we compared the microtubule cytoskeleton in DMD mice (mdx) versus mdx mice genetically altered to be Cx43-phosphorylation-deficient (mdxS3A). Reciprocally, we analyzed the microtubule cytoskeleton in mdx mice genetically altered to be Cx43-phospho-mimicking (mdxS3E). We found a link between the phospho-status of Connexin-43 and regulation of microtubule organization, in which phospho-dead Cx43 (S3A) inhibits improvements seen with Colchicine treatment in mdx mice, and phospho-mimic S3E promotes microtubule reorganization in mdx mice. A reduction in arrhythmias and fibrosis suggests an unsuspecting Cx43-microtubule link for translational corrective activities for DMD cardiomyopathy.

cell biology↗

bioRxiv2020

Connexin 43 hemichannels mediate spatial and temporal disease spread in ALS

Connexin 43 (Cx43) gap junctions and hemichannels mediate astrocyte intercellular communication in the central nervous system under normal conditions and may contribute to astrocyte-mediated neurotoxicity in amyotrophic lateral sclerosis (ALS). Here we show that astrocyte-specific knockout of Cx43 in a mouse model of ALS slows disease progression both spatially and temporally, provides motor neuron (MN) protection, and improves survival. In human ALS tissues and biofluids, we observe that higher levels of Cx43 correlate with accelerated disease progression. Using human iPSC-derived astrocytes (hiPSC-A) from both familial and sporadic ALS, we show that Cx43 is upregulated and that Cx43-hemichannels are enriched at the astrocyte membrane. We then demonstrate that the pharmacological blockade of Cx43-hemichannels in ALS astrocytes, during a specific temporal window, provides neuroprotection of hiPSC-MN and reduces ALS astrocyte-mediated neuronal hyperexcitability. Our data identify Cx43 hemichannels as novel conduits of astrocyte-mediated disease progression and a pharmacological target for disease-modifying ALS therapies.

neuroscience↗