Biology subjects

Martinez-Barbera, J. P.

Publications and source records attributed to Martinez-Barbera, J. P..

3 recordsLinked to original sources

bioRxiv2019

Galactose-modified duocarmycin prodrugs as senolytics

Senescence is a stable growth arrest that impairs the replication of damaged, old or preneoplastic cells, therefore contributing to tissue homeostasis. Senescent cells accumulate during ageing and are associated with diseases, such as cancer, fibrosis and many age-related pathologies. Recent evidence suggests that the selective elimination of senescent cells can be effective on the treatment of many of these senescence-associated diseases. A universal characteristic of senescent cells is that they display elevated activity of the lysosomal {beta}-galactosidase this has been exploited as a marker for senescence (senescence-associated {beta}-galactosidase activity). Consequently, we hypothesised that galactose-modified cytotoxic prodrugs will be preferentially processed by senescent cells, resulting in their selective killing. Here, we show that different galactose-modified duocarmycin (GMD) derivatives preferentially kill senescent cells. GMD prodrugs induce selective apoptosis of senescent cells in a lysosomal {beta}-galactosidase (GLB1)-dependent manner. GMD prodrugs can eliminate a broad range of senescent cells in culture, and treatment with a GMD prodrug enhances the elimination of bystander senescent cells that accumulate upon whole body irradiation or doxorubicin treatment of mice. Moreover, taking advantage of a mouse model of human adamantinomatous craniopharyngioma (ACP), we show that treatment with a GMD pro-drug result selectively reduced the number of {beta}-catenin-positive preneoplastic senescent cells, what could have therapeutic implications. In summary, the above results show that galactose-modified duocarmycin prodrugs behave as senolytics, suggesting that they could be used to treat a wide range of senescence-related pathologies.

cell biology↗

bioRxiv2018

Genetic approaches in mice demonstrate that neuro-mesodermal progenitors express T/Brachyury but not Sox2

Neural tube and somites have long been thought to derive from separate germ layers: the ectoderm and mesoderm. This concept was challenged by the discovery of neuro-mesodermal progenitors, a bi-potent cell population that gives rise to both spinal neural tube and somites. In line with their proposed potency, these cells are considered to co-express the neural marker Sox2 and the mesodermal marker T/Brachyury. We performed genetic lineage tracing in mouse embryos and confirmed that T-expressing cells give rise to both neural tube and mesoderm. Surprisingly, however, Sox2-expressing cell derivatives colonise only the neural tube after embryonic day 8.5. Deletion of Sox2 in T-expressing cells was compatible with an otherwise normal neural tube and paraxial mesoderm. Moreover, Sox2 expression is absent from the chordoneural hinge, where neuro-mesodermal progenitors are located. Our findings demonstrate that neuro-mesodermal progenitors express T but not Sox2, suggesting the need for re-evaluation of the neuro-mesodermal progenitor hypothesis.

developmental biology↗

bioRxiv2017

WDR11-mediated Hedgehog signalling defects underlie a new ciliopathy related to Kallmann syndrome

WDR11 has been implicated in congenital hypogonadotropic hypogonadism (CHH) and Kallmann syndrome (KS), human developmental genetic disorders defined by delayed puberty and infertility. However, WDR11s role in development is poorly understood. Here we report that WDR11 modulates the Hedgehog (Hh) signalling pathway and is essential for ciliogenesis. Disruption of WDR11 expression in mouse and zebrafish results in phenotypic characteristics associated with defective Hh signalling, accompanied by dysgenesis of ciliated tissues. Wdr11 null mice also exhibit early onset obesity. We found that WDR11 shuttles from the cilium to the nucleus in response to Hh signalling. WDR11 was also observed to regulate the proteolytic processing of GLI3 and cooperate with EMX1 transcription factor to induce the expression of downstream Hh pathway genes and gonadotrophin releasing hormone production. The CHH/KS-associated human mutations result in loss-of-function of WDR11. Treatment with the Hh agonist purmorphamine partially rescued the WDR11-haploinsufficiency phenotypes. Our study reveals a novel class of ciliopathy caused by WDR11 mutations and suggests that CHH/KS may be a part of the human ciliopathy spectrum.

developmental biology↗