CD300f immune receptor contributes to healthy aging by regulating inflammaging, metabolism, and cognitive decline.

Emerging evidence suggests that immune receptors may participate in many aging-related processes such as energy metabolism, inflammation, and cognitive decline. CD300f, a TREM2-like lipid-sensing immune receptor, is an exceptional receptor as it integrates activating and inhibitory cell-signaling pathways that modulate inflammation, efferocytosis, and microglial metabolic fitness. We hypothesize that CD300f can regulate systemic aging-related processes and ultimately healthy lifespan. We closely followed several cohorts of two strains of CD300f-/- and WT mice of both sexes for 30 months and observed an important reduction in lifespan and healthspan in knockout mice. This was associated with systemic inflammaging, increased cognitive decline, reduced brain glucose uptake observed by 18FDG PET scans, enrichment in microglial aging/neurodegeneration phenotypes, proteostasis alterations, senescence, increased frailty, and sex-dependent systemic metabolic changes. Moreover, the absence of CD300f altered macrophage immunometabolic phenotype. Taken together, we provide strong evidence suggesting that myeloid cell CD300f immune receptor contributes to healthy aging.

Mucins Shed from the Laminated Layer in Cystic Echinococcosis Are Captured by Kupffer Cells via the Lectin Receptor Clec4F.

Cystic echinococcosis is caused by the larval stages (hydatids) of cestode parasites belonging to the species cluster Echinococcus granulosus sensu lato, with E. granulosus sensu stricto being the main infecting species. Hydatids are bladderlike structures that attain large sizes within various internal organs of livestock ungulates and humans. Hydatids are protected by the massive acellular laminated layer (LL), composed mainly of mucins. Parasite growth requires LL turnover, and abundant LL-derived particles are found at infection sites in infected humans, raising the question of how LL materials are dealt with by the hosts. In this article, we show that E. granulosus sensu stricto LL mucins injected into mice are taken up by Kupffer cells, the liver macrophages exposed to the vascular space. This uptake is largely dependent on the intact mucin glycans and on Clec4F, a C-type lectin receptor which, in rodents, is selectively expressed in Kupffer cells. This uptake mechanism operates on mucins injected both in soluble form intravenously (i.v.) and in particulate form intraperitoneally (i.p.). In mice harboring intraperitoneal infections by the same species, LL mucins were found essentially only at the infection site and in the liver, where they were taken up by Kupffer cells via Clec4F. Therefore, shed LL materials circulate in the host, and Kupffer cells can act as a sink for these materials, even when the parasite grows in sites other than the liver.

SPATS1 (spermatogenesis-associated, serine-rich 1) is not essential for spermatogenesis and fertility in mouse.

SPATS1 (spermatogenesis-associated, serine-rich 1) is an evolutionarily conserved, testis-specific protein that is differentially expressed during rat male meiotic prophase. Some reports have suggested a link between SPATS1 underexpression/mutation and human pathologies such as male infertility and testicular cancer. Given the absence of functional studies, we generated a Spats1 loss-of-function mouse model using CRISPR/Cas9 technology. The phenotypic analysis showed no overt phenotype in Spats1-/- mice, with both males and females being fertile. Flow cytometry and histological analyses did not show differences in the testicular content and histology between WT and knockout mice. Moreover, no significant differences in sperm concentration, motility, and morphology, were observed between WT and KO mice. These results were obtained both for young adults and for aged animals. Besides, although an involvement of SPATS1 in the Wnt signaling pathway has been suggested, we did not detect changes in the expression levels of typical Wnt pathway-target genes in mutant individuals. Thus, albeit Spats1 alteration might be a risk factor for male testicular health, we hereby show that this gene is not individually essential for male fertility and spermatogenesis in mouse.

Long-Term Effect of Environmental Enrichment on Reproductive Performance of Swiss Webster Mice and Their Female Offspring.

The aim of this study was to evaluate the effect of an environmental enrichment (EE) plan on the reproductive performance of Swiss Webster mice and their female offspring used as recipients for embryo transfer. A total of 54 breeder mice and 60 F1 females, used as foster mothers, were allocated in two experimental groups to receive or not receive EE for physical well-being. Reproductive outcomes of the Swiss trios such as birth rate and pup number, litter size, pups' weight at weaning, interlitter interval and time to first litter were analyzed. Environmental enrichment significantly increased pups weight from breeding trios compared to the control group (14.4 ± 0.1 vs. 13.8g ± 0.1, EE vs. control, respectively; p < 0.01). Other parameters did not differ between both groups. Reproductive parameters of female offspring used as recipients for embryo transfer did not differ among groups subjected or not to EE. These data demonstrate that the EE protocol applied in Swiss Webster breeder mice positively enhanced pups weight, and did not interfere with other reproductive outcomes. In conclusion, this study supports the implementation of EE plans usually applied for animal welfare in mouse facilities with slight improvement in reproductive performance.

Colony aging affects the reproductive performance of Swiss Webster females used as recipients for embryo transfer.

The objective was to evaluate the influence of colony aging in a Swiss Webster (SW) outbred stock used as recipients for embryo transfer. In the first study, a retrospective analysis was performed throughout several generations during a 38-month period in 2,398 embryos transferred to 108 SW recipients. A decrease in the percentage of live pups from transferred embryos was found at the end of the period. Impairment occurred due to the incidence of maternal cannibalism that increased from 0% to 67-100% (P<0.05), while pregnancy rate (pregnant/transferred recipients) and number of pups per delivered female were not affected throughout the period (P=NS). A following study was carried out to compare the reproductive performance of SW stock vs. B6D2F1 hybrid females in a 5-year interval. The study was conducted on a total of 893 embryos transferred to 40 females (20 SW and 20 B6D2F1) in Year #1, and 514 embryos transferred to 30 females (15 SW and 15 B6D2F1) in Year #5. No cases of maternal cannibalism were found on Year #1 in any of the strains (0/10 and 0/10). However, an incidence of 44,4% (4/9) was seen on Year #5 for SW, while for B6D2F1 the incidence was 0% (0/12) (P<0.05). Further examination of the uterus showed endometrial cysts and abnormal implantation sites in SW on Year #5 but not in B6D2F1 females. In conclusion, this study reports an impairment of the reproductive performance of an early aged SW outbred stock colony mainly due to the occurrence of maternal cannibalism. This finding has important implications for embryo transfer programs conducted in mouse facilities.

Minimum volume Spatula MVD vitrification method improves embryo survival compared to traditional slow freezing, both for in vivo and in vitro produced mice embryos.

This study was conducted to compare the effect of minimum volume Spatula MVD vitrification (VIT) versus traditional slow freezing (SLF) of mouse embryos. A total of 2,617 8-cell in vivo derived and 2-cell in vitro produced B6D2 mouse embryos were subjected to freezing/thawing or vitrification/warming, while fresh embryos were used as control group. Embryo recovery, survival and development rate, pregnancy rate and offspring production were analyzed. In Experiment 1, 8-cell in vivo derived embryos were subjected to in vitro culture, resulting in greater survival and development rates at 3.5 days post coitum stage in VIT than in SLF group (P < 0.05). Although both methods reached an acceptable hatching rate (41.0% and 49.7% for VIT and SLF, respectively; P=NS), it was significantly lower respect to the control group (67.8%, P < 0.01). In Experiment 2, 2-cell in vitro produced mouse embryos showed a similar recovery rate from the device after freezing/thawing or vitrification/warming (∼84%), however survival rate was significantly higher for vitrified/warmed (94.7%) than frozen/thawed embryos (85.1%; P < 0.01). Vitrified/warmed and control fresh embryos were transferred to surrogate mothers, revealing no differences both in pregnancy and offspring production rates. Our data demonstrate that minimum volume Spatula MVD method is a simple home-made useful technique for vitrification of 2-cell and 8-cell mouse embryos produced either in vitro or in vivo.

Anti-aggressive effect elicited by coca-paste in isolation-induced aggression of male rats: influence of accumbal dopamine and cortical serotonin.

Coca-paste (CP), an illicit drug of abuse, has been frequently associated with aggressive and impulsive behaviors in humans. However, preclinical studies have not been carried out in order to characterize CP effects on aggression. The acute effect of CP, cocaine and caffeine (the main adulterant present in seized samples) on aggression was assessed using the isolation-induced aggression paradigm in male rats. The dopaminergic (DA) neurotransmission in the nucleus accumbens (NAcc) and serotonergic (5-HT) activity in the frontal cortex were explored. CP and cocaine induced a similar anti-aggressive effect on isolated rats although CP-treated animals showed a shorter latency to the first attack. Aggressive behavior was not increased per se by caffeine. Social investigation time was slightly reduced only by cocaine while exploratory activity and time spent walking were increased by the three drugs. Accumbal DA levels were significantly augmented by CP, cocaine and caffeine, although differences in DOPAC and HVA levels were evidenced. A decrease in DA turnover was only observed after CP and cocaine administration. Increased cortical 5-HT levels with a concomitant decrease in 5-HT turnover were observed after CP and cocaine whereas caffeine did not alter it. As cocaine but not caffeine reduced aggression, it seems like cocaine content was mainly responsible for CP anti-aggressive action; however, the presence of caffeine in CP may have a role in the shorter latency to attack compared to cocaine. Despite the increase in NAcc DA, the enhancement of cortical 5-HT levels can likely underlie the anti-aggression observed in CP-treated animals.

Coca-paste seized samples characterization: chemical analysis, stimulating effect in rats and relevance of caffeine as a major adulterant.

Coca-paste (CP) is a drug of abuse that so far has not been extensively characterized. CP is an intermediate product of the cocaine alkaloid extraction process from coca leaves, hence it has a high content of cocaine base mixed with other chemical substances (impurities) and it is probably adulterated when it reaches the consumers. Despite its high prevalence and distribution through South America, little is known about its effects on the central nervous system. In the present study, a chemical analysis of CP samples from different police seizures was performed to determine the cocaine base content and the presence and content of impurities and adulterants. Some CP representative samples were selected to study the effects on the locomotor activity induced after acute systemic administration in rats as a measure of its stimulant action. The behavioral response was compared to equivalent doses of cocaine. As expected, cocaine was the main component in most of the CP samples assayed. Caffeine was the only active adulterant detected. Interestingly, several CP samples elicited a higher stimulant effect compared to that observed after cocaine when administered at equivalent doses of cocaine base. Combined treatment of cocaine and caffeine, as surrogate of different CP samples mimicked their stimulant effect. We demonstrated that cocaine and caffeine are the main components responsible for the CP-induced stimulant action while the contribution of the impurities was imperceptible.

Prefrontal cortex lesions cause only minor effects on the hyperlocomotion induced by MK-801 and its reversal by clozapine.

The non-competitive NMDA receptor antagonist MK-801 elicits a behavioural syndrome in rodents characterized by hyperlocomotion and stereotypies, which is antagonized by antipsychotic drugs. NMDA receptor antagonists increase prefrontal cortex (PFC) activity in rodents, as assessed by electrophysiological and neurochemical measures. The increase in glutamate outflow induced by systemic MK-801 administration in the medial PFC (mPFC) is prevented by the local administration of clozapine (Clz). In the present study, we examine whether a PFC lesion alters the behavioural syndrome induced by MK-801 in rats and the Clz-induced antagonism of MK-801 actions. We evaluated the hyperlocomotion, stereotypies and other behavioural changes induced by MK-801 in the open field and the effect of electrolytic lesions of the mPFC, and of cortical transection on the behavioural syndrome induced by MK-801 and its reversal by Clz. MK-801 (0.1-0.2 mg/kg i.p.) reduced rearings but only the higher dose induced hyperlocomotion. At this dose, MK-801 also increased disorganized movements, head weavings, and induced ataxia signs. An electrolytic lesion of the mPFC markedly reduced the number of rearings pre-treatment but caused a very slight attenuation of MK-801-induced hyperlocomotion. Cortical transection did not significantly alter MK-801 effects. Clz administration (1 mg/kg s.c.) significantly attenuated hyperlocomotion, head weavings and ataxia signs induced by MK-801 but did not prevent the decrease in rearings. The effect of Clz was essentially unaffected by electrolytic lesions of the mPFC. These results show that MK-801-induced motor syndrome and its reversal by Clz are mostly independent on PFC integrity.