Biology subjects

Calo, L.

Publications and source records attributed to Calo, L..

3 recordsLinked to original sources

bioRxiv2023

Endolysin B: A new archetype in M. tuberculosis treatment

So far it is thanks to antibiotics that illnesses, such as Tuberculosis (TB), are treatable. However, antimicrobial misuse combined with Mycobacterium tuberculosis phenotypic plasticity are nullifying the effects of the existing therapies. As a result, increasingly people are dying (one person dies of TB every 20 seconds), especially due to the rise of multi-and extensively drug-resistant strains. There is indeed a urgent need for new and more effective therapies, which should match the requirement of avoiding the rise in drug resistance. Among them, the use of bacteriophage - bacteria-restricted viruses - or simply phage lytic enzyme (i.e., endolysin) represents one of the most promising alternatives. All phages encode for the endolysin A (LysA), which degrades the bacteria cell wall, finally leading to the release of the newly synthesized virions. Nevertheless, mycobacteriophages (bacterial viruses selectively infecting mycobacteria), evolved the additional endolysin B (LysB) to selectively damage the complex mycobacteria cell wall, and to evade from their host. LysB, owing a lipolytic enzyme, can degrade the thick mycolic acid layer, and hence disrupt the integrity of the mycobacterial membrane. Despite its key role in mediating mycobacteria lysis, the molecular mechanism regulating LysB binding to its target remains poorly characterized. Herein, we selected Ms6LysB and created a fluorescent engineered version as a proxy to analyze LysB binding qualitatively and quantitatively to both the fast-growing non-pathogenic Mycobacterium smegmatis and the slow-growing pathogenic M. tuberculosis. Additionally, we shed light on LysB antimicrobial activity upon M. tuberculosis infection, by using alveolar-like mouse macrophages (mAMs) as a cellular model that closely recapitulates the natural niche of M. tuberculosis infection. Our study provides the proof-of-principle that Ms6 LysB binding to the outer mycobacterial membrane can impair M. tuberculosis growth homeostasis and that LysB retain its lytic properties even when internalized by mAMs. This lays the groundwork for the use of LysB as a new therapeutic strategy to undermine M. tuberculosis infection.

microbiology↗

bioRxiv2020

CSPα reduces aggregates and rescues striatal dopamine release in αsynuclein transgenic mice

Synuclein aggregation at the synapse is an early event in Parkinsons disease and is associated with impaired striatal synaptic function and dopaminergic neuronal death. The cysteine string protein (CSP) and synuclein have partially overlapping roles in maintaining synaptic function and mutations in each cause neurodegenerative diseases. CSP is a member of the DNAJ/HSP40 family of co-chaperones and like synuclein, chaperones the SNARE complex assembly and neurotransmitter release. Synuclein can rescue neurodegeneration in CSPKO mice. However, whether synuclein aggregation alters CSP expression and function is unknown. Here we show that synuclein aggregation at the synapse induces a decrease in synaptic CSP and a reduction in the complexes that CSP forms with HSC70 and STGa. We further show that viral delivery of CSP rescues in vitro the impaired vesicle recycling in PC12 cells with synuclein aggregates and in vivo reduces synaptic synuclein aggregates restoring normal dopamine release in 1-120hsyn mice. These novel findings reveal a mechanism by which synuclein aggregation alters CSP at the synapse, and show that CSP rescues synuclein aggregation-related phenotype in 1-120hsyn mice similar to the effect of synuclein in CSPKO mice. These results implicate CSP as a potential therapeutic target for the treatment of early-stage PD.

neuroscience↗

bioRxiv2018

Depopulation of α-synuclein aggregates is associated with rescue of dopamine neuron dysfunction and death in a new Parkinson disease model

Parkinsons Disease (PD) is characterized by the presence of -synuclein aggregates known as Lewy bodies and Lewy neurites, whose formation is linked to disease development. The causal relation between -synuclein aggregates and PD is not well understood. We generated a new transgenic mouse line (MI2) expressing human, aggregation-prone truncated 1-120 -synuclein under the control of the tyrosine hydroxylase promoter. MI2 mice exhibit progressive aggregation of -synuclein in dopaminergic neurons of the substantia nigra pars compacta and their striatal terminals. This is associated with a progressive reduction of striatal dopamine release, reduced striatal innervation and significant nigral dopaminergic nerve cell death starting from 6 and 12 months of age, respectively. Overt impairment in motor behavior was found in MI2 mice at 20 months of age, when 50% of dopaminergic neurons are lost. These changes were associated with an increase in the number and density of 20-500nm -synuclein species as shown by dSTORM. Treatment with the oligomer modulator anle138b, from 9-12 months of age, restored striatal dopamine release and prevented dopaminergic cell death. These effects were associated with a reduction of the inner density of -synuclein aggregates and an increase in dispersed small -synuclein species as revealed by dSTORM. The MI2 mouse model recapitulates the progressive dopaminergic deficit observed in PD, showing that early synaptic dysfunction precedes dopaminergic axonal loss and neuronal death that become associated with a motor deficit upon reaching a certain threshold. Our data also provide new mechanistic insight for the effect of anle138bs function in vivo supporting that targeting -synuclein aggregation is a promising therapeutic approach for PD.

neuroscience↗