Histopathology of laboratory-reared Nothobranchius fishes: Mycobacterial infections versus neoplastic lesions

Immune aging in annual killifish

Turquoise killifish (Nothobranchius furzeri) evolved a naturally short lifespan of about six months and exhibit aging hallmarks that affect multiple organs. These hallmarks include protein aggregation, telomere shortening, cellular senescence, and systemic inflammation. Turquoise killifish possess the full spectrum of vertebrate-specific innate and adaptive immune system. However, during their recent evolutionary history, they lost subsets of mucosal-specific antibody isoforms that are present in other teleosts. As they age, the immune system of turquoise killifish undergoes dramatic cellular and systemic changes. These changes involve increased inflammation, reduced antibody diversity, an increased prevalence of pathogenic microbes in the intestine, and extensive DNA damage in immune progenitor cell clusters. Collectively, the wide array of age-related changes occurring in turquoise killifish suggest that, despite an evolutionary separation spanning hundreds of millions of years, teleosts and mammals share common features of immune system aging. Hence, the spontaneous aging observed in the killifish immune system offers an excellent opportunity for discovering fundamental and conserved aspects associated with immune system aging across vertebrates. Additionally, the species' naturally short lifespan of only a few months, along with its experimental accessibility, offers a robust platform for testing interventions to improve age-related dysfunctions in the whole organism and potentially inform the development of immune-based therapies for human aging-related diseases.

Crosstalk of oxidative stress, inflammation, apoptosis, and autophagy under reactive oxygen stress involved in difenoconazole-induced kidney damage in carp

Difenoconazole is a commonly used triazole fungicide in agricultural production. Because of its slow degradation and easy accumulation in the environment, it seriously endangers both animal health and the ecological environment. Therefore, it is hoped that the effects on carp kidneys can be studied by simulating difenoconazole residues in the environment. The experiment was designed with two doses (0.488 mg/L, 1.953 mg/L) as exposure concentrations of difenoconazole for 4 d. Histopathological results showed that difenoconazole could cause severe damage to the kidney structure and extensive inflammatory cell infiltration in carp. Elevated levels of Creatinine, and BUN suggested the development of kidney damage. The DHE fluorescence probe's result suggested that difenoconazole might cause reactive oxygen species (ROS) to accumulate in the kidney of carp. Difenoconazole was found to increase MDA levels while decreasing the activities of CAT, SOD, and GSH-PX, according to biochemical indicators. In addition, difenoconazole could up-regulate the transcription levels of inflammatory factors tnf-α, il-6, il-1β, and inos. At the same time, it inhibited the transcription level of il-10 and tgf-β1. The TUNEL test clearly showed that difenoconazole induced apoptosis in the kidney and vastly raised the transcript levels of apoptosis-related genes p53, caspase9, caspase3, and bax while inhibiting the expression of Bcl-2, fas, capsase8. Additionally, TEM imaging showed that clearly autophagic lysosomes and autophagosomes were formed. Elevated levels of LC3II protein expression, increased transcript levels of the autophagy-related gene atg5 as well as decreased transcript levels of p62 represented the generation of autophagy. In conclusion, the study illustrated that oxidative stress, inflammation, apoptosis, and autophagy all played roles in difenoconazole-induced kidney injury in carp, which was closely linked to ROS production. This work provides a valuable reference for studying the toxicity of difenoconazole to aquatic organisms.

Beyond the Lab: What We Can Learn about Cancer from Wild and Domestic Animals

Cancer research has benefited immensely from the use of animal models. Several genetic tools accessible in rodent models have provided valuable insight into cellular and molecular mechanisms linked to cancer development or metastasis and various lines are available. However, at the same time, it is important to accompany these findings with those from alternative or non-model animals to offer new perspectives into the understanding of tumor development, prevention, and treatment. In this review, we first discuss animals characterized by little or no tumor development. Cancer incidence in small animals, such as the naked mole rat, blind mole rat and bats have been reported as almost negligible and tumor development may be inhibited by increased defense and repair mechanisms, altered cell cycle signaling and reduced rates of cell migration to avoid tumor microenvironments. On the other end of the size spectrum, large animals such as elephants and whales also appear to have low overall cancer rates, possibly due to gene replicates that are involved in apoptosis and therefore can inhibit uncontrolled cell cycle progression. While it is important to determine the mechanisms that lead to cancer protection in these animals, we can also take advantage of other animals that are highly susceptible to cancer, especially those which develop tumors similar to humans, such as carnivores or poultry. The use of such animals does not require the transplantation of malignant cancer cells or use of oncogenic substances as they spontaneously develop tumors of similar presentation and pathophysiology to those found in humans. For example, some tumor suppressor genes are highly conserved between humans and domestic species, and various tumors develop in similar ways or because of a common environment. These animals are therefore of great interest for broadening perspectives and techniques and for gathering information on the tumor mechanisms of certain types of cancer. Here we present a detailed review of alternative and/or non-model vertebrates, that can be used at different levels of cancer research to open new perspectives and fields of action.