DNA sperm damage correlates with nuclear ultrastructural sperm defects in teratozoospermic men

Andrologia 2012 44(1):59-65

F Skowronek 1 2, G Casanova 2, J Alciaturi 1, A Capurro 3, L Cantu 4, J M Montes 4, R Sapiro 1

1 Laboratory of Molecular Biology of Reproduction, Department of Histology & Embryology, School of Medicine, Montevideo, Uruguay; 2 Department of Cellular and Molecular Biology and Electron Microscopy Unit, School of Science, Montevideo, Uruguay; 3 Unit of Human Reproduction, Pereira-Rossell Hospital Center, Montevideo, Uruguay; 4 Fertilab Canelones, Montevideo, Uruguay

DOI: 10.1111/j.1439-0272.2010.01106.x
PMID: 21592172
Pubmed: https://pubmed.ncbi.nlm.nih.gov/21592172
Texto completo: https://doi.org/10.1111/j.1439-0272.2010.01106.x

Abstract:
Sperm morphology has consistently been the best indicator of male fertility. Transmission electron microscopy currently provides the most information on the subcellular details of sperm structure. Recently, assessment of sperm DNA damage has been employed to assess fertility potential. The purpose of this work was to link sperm DNA damage, evaluated by an intercalated fluorescent dye, with the structural characteristics of sperm. Conventional semen analysis was performed on samples from men undergoing fertility evaluation. Thirty men were evaluated and assigned to three subgroups based on strict criteria for sperm morphology: normal morphology (>14% normal forms), intermediate morphology (5-14% normal forms), and poor morphology (<5% normal forms). By quantifying acridine orange-positive cells and ultrastructural sperm defects, we found that the poor morphology pattern group showed a positive association between sperm carrying damaged DNA and the percentage of sperm nucleus with vacuoles (P = 0.01). No statistically significant correlations were established in other ultrastructural characteristics of sperm, including immature chromatin, lytic changes, or abnormal sperm tails. These results suggest that zones without chromatin in the sperm nucleus reflect underlying chromosomal or DNA defects in severe teratozoospermic men. This association should be considered in the evaluation of male fertility.

Modulation of astrocytic mitochondrial function by dichloroacetate improves survival and motor performance in inherited amyotrophic lateral sclerosis

PLoS One 2012 7(4):e34776

Ernesto Miquel 1 #, Adriana Cassina 2 3 #, Laura Martínez-Palma 1, Carmen Bolatto 1, Emiliano Trías 4, Mandi Gandelman 1, Rafael Radi 2 3, Luis Barbeito 5 3, Patricia Cassina 1 3

1 Departamento de Histología y Embriología, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay 2 Departamento de Bioquímica, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay 3 CEINBIO, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay 4 Instituto de Investigaciones Biológicas Clemente Estable, Montevideo, Uruguay 5 Institut Pasteur de Montevideo, Montevideo, Uruguay 6 Federal University of Rio de Janeiro, Brazil

DOI: 10.1371/journal.pone.0034776
PMID: 22509356
Pubmed: https://pubmed.ncbi.nlm.nih.gov/22509356
Texto completo: https://dx.plos.org/10.1371/journal.pone.0034776

Abstract:
Mitochondrial dysfunction is one of the pathogenic mechanisms that lead to neurodegeneration in Amyotrophic Lateral Sclerosis (ALS). Astrocytes expressing the ALS-linked SOD1(G93A) mutation display a decreased mitochondrial respiratory capacity associated to phenotypic changes that cause them to induce motor neuron death. Astrocyte-mediated toxicity can be prevented by mitochondria-targeted antioxidants, indicating a critical role of mitochondria in the neurotoxic phenotype. However, it is presently unknown whether drugs currently used to stimulate mitochondrial metabolism can also modulate ALS progression. Here, we tested the disease-modifying effect of dichloroacetate (DCA), an orphan drug that improves the functional status of mitochondria through the stimulation of the pyruvate dehydrogenase complex activity (PDH). Applied to astrocyte cultures isolated from rats expressing the SOD1(G93A) mutation, DCA reduced phosphorylation of PDH and improved mitochondrial coupling as expressed by the respiratory control ratio (RCR). Notably, DCA completely prevented the toxicity of SOD1(G93A) astrocytes to motor neurons in coculture conditions. Chronic administration of DCA (500 mg/L) in the drinking water of mice expressing the SOD1(G93A) mutation increased survival by 2 weeks compared to untreated mice. Systemic DCA also normalized the reduced RCR value measured in lumbar spinal cord tissue of diseased SOD1(G93A) mice. A remarkable effect of DCA was the improvement of grip strength performance at the end stage of the disease, which correlated with a recovery of the neuromuscular junction area in extensor digitorum longus muscles. Systemic DCA also decreased astrocyte reactivity and prevented motor neuron loss in SOD1(G93A) mice. Taken together, our results indicate that improvement of the mitochondrial redox status by DCA leads to a disease-modifying effect, further supporting the therapeutic potential of mitochondria-targeted drugs in ALS.

2012_Miquel et al.pdf

Brain androgen receptor expression correlates with seasonal changes in the behavior of a weakly electric fish, Brachyhypopomus gauderio

Horm Behav 2010 58(5):729-36

Paula Pouso b d, Laura Quintana a, Carmen Bolatto d, Ana C. Silva b c

a Departamento de Neurofisiología, Instituto de Investigaciones Biológicas Clemente Estable, Montevideo 11600, Uruguay b Unidad Bases Neurales de la Conducta, Instituto de Investigaciones Biológicas Clemente Estable, Montevideo 11600, Uruguay c Laboratorio de Neurociencias, Facultad de Ciencias, Universidad de la República, Montevideo 11400, Uruguay d Departamento Histología y Embriología, Facultad de Medicina, Universidad de la República, Montevideo 11800, Uruguay

DOI: 10.1016/j.yhbeh.2010.07.005
PMID: 20688071
Pubmed: https://pubmed.ncbi.nlm.nih.gov/20688071
Texto completo: https://linkinghub.elsevier.com/retrieve/pii/S0018-506X(10)00201-1

Abstract:
Seasonal breeders are superb models for understanding natural relationships between reproductive behavior and its neural bases. We investigated the cellular bases of hormone effects in a weakly pulse-type electric fish with well-defined hormone-sensitive communication signals. Brachyhypopomus gauderio males emit social electric signals (SESs) consisting of rate modulations of the electric organ discharge during the breeding season. This discharge is commanded by a medullary pacemaker nucleus (PN), composed of pacemaker and relay neurons. We analyzed the contribution of androgen receptor (AR) expression to the seasonal generation of SESs, by examining the presence of ARs in the PN in different experimental groups: breeding, non-breeding, and testosterone (T)-implanted non-breeding males. AR presence and distribution in the CNS was assessed through western blotting and immunohistochemistry using the PG-21 antibody, which was raised against the human AR. We found AR immunoreactivity, for the first time in a pulse-type Gymnotiform, in several regions throughout the brain. In particular, this is the first report to reveal the presence of AR in both pacemaker and relay neurons within the Gymnotiform PN. The AR immunoreactivity was present in breeding males and could be induced in T-implanted non-breeding males. This seasonal and T-induced AR expression in the PN suggests that androgens may play an important role in the generation of SESs by modulating intrinsic electrophysiological properties of pacemaker and relay neurons.

Extracellular ATP and the P2X7 receptor in astrocyte-mediated motor neuron death: implications for amyotrophic lateral sclerosis

J Neuroinflammation 2010 7:33

Mandi Gandelman 1 2, Hugo Peluffo 1 2, Joseph S Beckman 3, Patricia Cassina 2, Luis Barbeito 1 4

1 Neurodegeneration Laboratory, Institut Pasteur, Montevideo, Uruguay 2 Departamento de Histología, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay 3 Linus Pauling Institute, Oregon State University, Corvallis, Oregon 97331, USA 4 Instituto de Investigaciones Biológicas Clemente Estable, Montevideo, Uruguay

DOI: 10.1186/1742-2094-7-33
PMID: 20534165
Pubmed: https://pubmed.ncbi.nlm.nih.gov/20534165
Texto completo: https://jneuroinflammation.biomedcentral.com/articles/10.1186/1742-2094-7-33

Abstract:
Background: During pathology of the nervous system, increased extracellular ATP acts both as a cytotoxic factor and pro-inflammatory mediator through P2X(7) receptors. In animal models of amyotrophic lateral sclerosis (ALS), astrocytes expressing superoxide dismutase 1 (SOD1G93A) mutations display a neuroinflammatory phenotype and contribute to disease progression and motor neuron death. Here we studied the role of extracellular ATP acting through P2X(7) receptors as an initiator of a neurotoxic phenotype that leads to astrocyte-mediated motor neuron death in non-transgenic and SOD1G93A astrocytes. Methods: We evaluated motor neuron survival after co-culture with SOD1G93A or non-transgenic astrocytes pretreated with agents known to modulate ATP release or P2X(7) receptor. We also characterized astrocyte proliferation and extracellular ATP degradation. Results: Repeated stimulation by ATP or the P2X(7)-selective agonist BzATP caused astrocytes to become neurotoxic, inducing death of motor neurons. Involvement of P2X(7) receptor was further confirmed by Brilliant blue G inhibition of ATP and BzATP effects. In SOD1G93A astrocyte cultures, pharmacological inhibition of P2X(7) receptor or increased extracellular ATP degradation with the enzyme apyrase was sufficient to completely abolish their toxicity towards motor neurons. SOD1G93A astrocytes also displayed increased ATP-dependent proliferation and a basal increase in extracellular ATP degradation. Conclusions: Here we found that P2X(7) receptor activation in spinal cord astrocytes initiated a neurotoxic phenotype that leads to motor neuron death. Remarkably, the neurotoxic phenotype of SOD1G93A astrocytes depended upon basal activation the P2X(7) receptor. Thus, pharmacological inhibition of P2X(7) receptor might reduce neuroinflammation in ALS through astrocytes.