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nnate immune responses to pathogens, mediated by activation of pattern recognition receptors and downstream signal transduction cascades, trigger rapid transcriptional and epigenetic changes to support increased expression of pro-inflammatory cytokines and other effector molecules. Innate immune cells also rapidly rewire their metabolism. The most prominent metabolic alteration following innate immune activation is rapid up-regulation of glycolysis. In this mini-review, we summarize recent advances regarding the mechanisms of rapid glycolytic activation in innate immune cells, highlighting the relevant signaling components. We also discuss the impact of glycolytic activation on inflammatory responses, including the recently elucidated links of metabolism and epigenetics. Finally, we highlight unresolved mechanistic details of glycolytic activation and possible avenues of future research in this area.
Capturing the mechanisms leading to the local extirpation of a species in deep time is a challenge. Here, by combining stable oxygen and carbon isotopic analyses on benthic and planktonic foraminifera and the otoliths of pelagic and benthic fish species, we reveal the paleoceanographic regime shifts that took place in the eastern Mediterranean from 7.2 to 6.5 Ma, in the precursor phase to the Messinian salinity crisis, and discuss the fish response to these events. The stepwise restriction of the Mediterranean–Atlantic gateway impacted the metabolism of fishes in the Mediterranean, particularly those dwelling in the lower, deeper part of the water column. An important shift in the Mediterranean paleoceanographic conditions took place between 6.951 and 6.882 Ma, from predominantly temperature to salinity control, which was probably related to stratification of the water column. A regime shift at 6.814 Ma, due to changes in the influx, source and/or preservation of organic matter, led to pelagic–benthic decoupling of the fish fauna. At that time, the oxygen isotopic composition of benthic fish otoliths reflects higher salinity in the lower part of the water column that is accompanied by a rapid fluctuation in the carbon isotopic composition (a proxy for the metabolic rate), ultimately leading to the local extirpation of the benthic species. Overall, our results confirm that otolith stable oxygen and carbon isotope ratios are reliable proxies for paleoceanographic studies and, when combined with those of foraminifera, can reveal life history changes and migration patterns of teleost fishes in deep time.
Within the realms of human and artificial intelligence, the concepts of consciousness and comprehension are fundamental distinctions. In the clinical sphere, patient awareness regarding medication and its physiological processes plays a crucial role in determining drug efficacy and outcomes. This article introduces a novel perspective on prescription practices termed “Ultra-Overt Therapy” (UOT). A review of current supporting evidence was conducted through a non-systematic search in PubMed and Google Scholar, focusing on concepts such as the “mind–body relationship,” “placebo response,” “neuroscience,” and “complementary medicine.” Our findings, rooted in the mechanisms of the “placebo effect,” the intricacies of “intersubjective therapy,” the potency of “interoceptive awareness,” and other domains of medical science, suggest that UOT holds theoretical promise. Future research endeavors focusing on these areas may elucidate the global impact of this method on medical treatment and patient care.
The paper describes a mathematical model of the molecular switches of cell survival, apoptosis, and necroptosis in cellular signaling pathways initiated by tumor necrosis factor 1. Based on experimental findings in the literature, we constructed a Petri net model based on detailed molecular reactions of the molecular players, protein complexes, post-translational modifications, and cross talk. The model comprises 118 biochemical entities, 130 reactions, and 299 edges. We verified the model by evaluating invariant properties of the system at steady state and by in silico knockout analysis. Applying Petri net analysis techniques, we found 279 pathways, which describe signal flows from receptor activation to cellular response, representing the combinatorial diversity of functional pathways.120 pathways steered the cell to survival, whereas 58 and 35 pathways led to apoptosis and necroptosis, respectively. For 65 pathways, the triggered response was not deterministic and led to multiple possible outcomes. We investigated the in silico knockout behavior and identified important checkpoints of the TNFR1 signaling pathway in terms of ubiquitination within complex I and the gene expression dependent on NF-κB, which controls the caspase activity in complex II and apoptosis induction. Despite not knowing enough kinetic data of sufficient quality, we estimated system’s dynamics using a discrete, semi-quantitative Petri net model.
Even more than 60 years after its introduction into the clinic, cyclophosphamide (CP), which belongs to the group of alkylating cytostatics, is indispensable for the treatment of cancer. This is despite the fact that its exact mechanism of action was unknown until a few years ago, and therefore, all attempts to improve the effectiveness of CP failed. The reason for not knowing the mechanism of action was the uncritical transfer of the chemical processes that lead to the formation of the actual alkylating CP metabolite phosphoreamide mustard (PAM) in vitro to in vivo conditions. In vitro—e.g., in cell culture experiments—PAM is formed by β-elimination of acrolein from the pharmacologically active CP metabolite aldophosphamide (ALD). In vivo, on the other hand, it is formed by enzymatic cleavage of ALD by phosphodiesterases (PDE) with the formation of 3-hydroxypropanal (HPA). The discovery of HPA as a cyclophosphamide metabolite, together with the discovery that HPA is a proapoptotic aldehyde and the discovery that the cell death event in therapy with CP is DNA-alkylation-initiated p53-controlled apoptosis, led to the formulation of a mechanism of action of CP and other oxazaphosphorine cytostatics (OX). This mechanism of action is presented here and is confirmed by newly developed CP-like compounds with lower toxicity and an order of magnitude better effectiveness.
Highlights
• Cryptic species are a so far overlooked aspect of environmental risk assessment.
• Multiple populations of four genetic lineages exposed in acute toxicity assays.
• Thiacloprid exposure shows up to 4-fold differences in tolerance among populations.
• Recent substance exposure probably triggers population-specific adaptive mechanisms.
• Population-level vulnerability calls for a shift in ecotoxicological methodology.
Abstract
Cryptic species are rarely considered in ecotoxicology, resulting in misleading outcomes when using a single morphospecies that encompasses multiple cryptic species. This oversight contributes to the lack of reproducibility in ecotoxicological experiments and promotes unreliable extrapolations. The important question of ecological differentiation and the sensitivity of cryptic species is rarely tackled, leaving a substantial knowledge gap regarding the vulnerability of individual cryptic species within species complexes. In times of agricultural intensification and the frequent use of pesticides, there is an urgent need for a better understanding of the vulnerability of species complexes and possible differences in adaptive processes. We used the cryptic species complex of the aquatic amphipod Gammarus roeselii, which comprises at least 13 genetic mtDNA lineages and spans from small-scale endemic lineages in Greece to a large-scale widely distributed lineage in central Europe. We exposed eleven populations belonging to four lineages to the neonicotinoid thiacloprid in an acute toxicity assay. We recorded various environmental variables in each habitat to assess the potential pre-exposure of the populations to contaminants. Our results showed that the populations differed up to 4-fold in their tolerances. The lineage identity had a rather minor influence, suggesting that the cryptic species complex G. roeselii does not differ significantly in tolerance to the neonicotinoid thiacloprid. However, the observed population differentiation implies that recent pre-exposure to thiacloprid (or similar substances) or general habitat contamination has triggered adaptive processes. Though, the extent to which these mechanisms are equally triggered in all lineages needs to be addressed in the future. Our study provides two key findings: Firstly, it shows that observed phylogenetic differences within the G. roeselii species complex did not reveal differences in thiacloprid tolerance. Second, it confirms that differentiation occurs at the population level, highlighting that susceptibility to toxicants is population-dependent. The population-specific differences were within the range of accepted intraspecific variability from a regulatory standpoint. From an evolutionary-ecological perspective, it remains intriguing to observe how persistent stresses will continue to influence tolerance and whether different populations are on distinct pathways of adaptation. Given that the potential selection process has only lasted a relatively short number of generations, it is crucial to monitor these populations in the future, as even brief exposure periods significantly impact evolutionary responses.
Lymphoma remains a significant global health challenge, contributing substantially to morbidity and mortality. Among the diverse subtypes of lymphoma, diffuse large B-cell lymphoma (DLBCL), an aggressive form, constitutes 30 to 40% of cases within Non-Hodgkin lymphomas (NHL). The evolving understanding of DLBCL subtypes emphasizes the urgent need for tailored treatment approaches, considering the substantial heterogeneity within this disease. Recognizing this, there is a critical demand for novel strategies and a deeper comprehension of resistance mechanisms against therapy to enhance the overall cure rates for individuals with DLBCL. Furthermore, it was shown that resistance to apoptosis is a common characteristic in cancer, often linked to the overexpression of anti-apoptotic BCL-2 proteins. To counteract this imbalance, the development of BH3-mimetics for inhibiting anti-apoptotic BCL-2 proteins is a promising strategy in cancer treatment. Venetoclax (ABT-199), a selective BCL-2 inhibitor, has demonstrated preclinical effectiveness against tumors and is the first BH3-mimetic approved for clinical use. Unfortunately, also resistance to ABT-199 can occur in patients, resulting in unfavorable treatment outcomes. This underscores the significance of ongoing research and clinical trials focused on elucidating and mitigating resistance mechanisms associated with ABT-199. The ultimate goal is to improve therapeutic strategies and enhance the effectiveness of ABT-199-based treatments. In this thesis our aim was to understand and explain the mechanisms behind the pre-existing resistance and the acquired resistance in DLBCL cell lines.
To investigate mechanisms of pre-existing resistance, we used specific DLBCL cell lines characterized by high BCL-2 to undergo cell death following ABT-199 treatment. These experiments are described under Part 1. To this end, we initially ruled out the possibility that protein expression patterns within the BCL-2 family contribute to resistance, as well as the expression of MDR1, which pumps out the drug from the cell, was not present in the selected cell DLBCL cell lines. Next, we selected two cell lines with high BCL-2 expression that displayed different responses to ABT-199 treatment. Our findings revealed notable variations in the binding patterns of anti-apoptotic and pro-apoptotic proteins upon treatment in the chosen sensitive (RIVA) and resistant (HBL-1) cell line. Upon observing the notable discrepancy in HBL-1 cells, where MCL-1 sequesters free BIM from BCL-2 in response to ABT-199, we hypothesized that MCL-1 was involved in the resistance. This was proven mechanistically by co-treatment with ABT-199 and the MCL-1 inhibitor S63845.
In the second part of the thesis, we investigated the role of the BH3-only protein NOXA in conferring resistance to cell death triggered by ABT-199 in the initially sensitive RIVA cell line. Employing CRISPR/Cas9-mediated knockout, we demonstrated that the absence of NOXA influenced sensitivity to ABT-199, both in vitro and in vivo. The absence of NOXA reinforced the role of MCL-1 as an anti-apoptotic protein, emphasizing its longer half-life and the newly identified interaction partner BIM. This hypothesis was validated through genetic silencing of MCL-1, resulting in the resensitization to ABT-199. Furthermore, in the absence of NOXA, we induced synergistic cell death through the co-treatment of ABT-199/S63845. Notably, we identified variations in the retranslocation of BAX in the presence and absence of NOXA, asserting that NOXA presence is crucial for BAX activation at the MOM, leading to pore formation with BAK.
The final section of the thesis explores the mechanism behind acquired resistance to ABT-199. To this end, RIVA cells were subjected to prolonged exposure to ABT-199. These adapted cells demonstrated the ability to overcome sensitivity to ABT-199 by elevating the expression of alternative anti-apoptotic proteins, specifically BCL-XL. To highlight this reliance, we utilized genetic silencing of BCL-XL, effectively resensitizing the cells to ABT-199. Furthermore, adapted RIVA cells exhibited sensitivity to co-treatment of ABT-199 with the BCL-XL inhibitor A1331852, resulting in synergistic cell death. In essence, our goal was to reveal the resistance mechanisms in order to identify better treatment strategies using BH3-mimetics in DLBCL patients. These findings highlight the importance of adopting a comprehensive strategy to address resistance mechanisms and improve the therapeutic effectiveness of ABT-199 in diverse combinations with other BH3-mimetics in treating DLBCL.
Highlights
• AIS is a useful tool for assessing the effects of repeated pulse exposures.
• Deltamethrin impacts aquatic communities at reported environmental exposure levels.
• Gammarus pulex as most sensitive species to repeated pulse exposures.
• MEC exceed the RAC derived from our results indicating a risk for aquatic organisms.
Abstract
Pesticides are considered to be one of the main causes of the decline in macroinvertebrate biodiversity in small streams. In particular, pyrethroids are detected in agricultural surface waters worldwide and pose a high risk to aquatic invertebrates. Due to their knock-down effect, even short pyrethroid exposure pulses can have significant short- and long-term effects on macroinvertebrate communities. Therefore, it is necessary to consider more realistic exposure scenarios for the environmental risk assessment of pyrethroids and, consequently, to obtain more realistic effect data by using multi-stressor test systems.
In an experimental setup with artificial indoor streams (AIS), four pyrethroid pulses simulated the exposure scenario of heavy rainfall events. Effects of these 12 h-exposures at different concentrations of deltamethrin (0.64 ng/L, 4 ng/L, 16 ng/L, 64 ng/L) with intervening recovery periods of six days were assessed on an aquatic community consisting of Gammarus pulex, Ephemera danica, Lumbriculus variegatus and Potamopyrgus antipodarum with various lethal and sub-lethal endpoints.
The mortality rate of G. pulex significantly increased with increasing deltamethrin concentrations, whereas the mean number of offspring significantly decreased (NOECoffspring: 16 ng/L, LOECoffspring: 64 ng/L). The biomass of L. variegatus decreased with increasing deltamethrin concentrations (NOECdry weight: 16 ng/L, LOECdry weight: 64 ng/L).
The findings of this study clearly demonstrate that 12 h-deltamethrin pulses at environmentally relevant concentrations adversely affect an aquatic community. Based on the results of this study a RAC value of 5.33 ng/L is assumed, which is below the concentrations measured in rivers of up to 58.8 ng/L. Unacceptable effects on the entire freshwater environment can therefore not be ruled out. The experimental AIS approach is a useful tool for assessing the effects of repeated pulse exposures that occur during surface runoff events.