The enormous societal impact of the ongoing COVID‐19 pandemic has been particularly harsh for some social groups, such as the elderly. Recently, it has been suggested that senescent cells could play ...a central role in pathogenesis by exacerbating the pro‐inflammatory immune response against SARS‐CoV‐2. Therefore, the selective clearance of senescent cells by senolytic drugs may be useful as a therapy to ameliorate the symptoms of COVID‐19 in some cases. Using the established COVID‐19 murine model K18‐hACE2, we demonstrated that a combination of the senolytics dasatinib and quercetin (D/Q) significantly reduced SARS‐CoV‐2‐related mortality, delayed its onset, and reduced the number of other clinical symptoms. The increase in senescent markers that we detected in the lungs in response to SARS‐CoV‐2 may be related to the post‐COVID‐19 sequelae described to date. These results place senescent cells as central targets for the treatment of COVID‐19, and make D/Q a new and promising therapeutic tool.
New treatments are necessary to reduce the social impact of COVID‐19. Using the murine model K18‐hACE2, we demonstrated that senolytics (D/Q) reduced SARS‐CoV‐2‐related mortality, delayed its onset, and reduced the number of other clinical symptoms.
Myeloid-derived suppressor cells (MDSCs) are immature heterogeneous myeloid cells that expand in pathologic conditions as cancer, trauma, and infection. Although characterization of MDSCs is ...continuously revisited, the best feature is their suppressor activity. There are many markers for MDSC identification, it is distinctive that they express inducible nitric oxide synthase (iNOS) and arginase 1, which can mediate immune suppression. MDSCs can have a medullary origin as a result of emergency myelopoiesis, but also can have an extramedullary origin. Early studies on
Trypanosoma cruzi
infection showed severe immunosuppression, and several mechanisms involving parasite antigens and host cell mediators were described as inhibition of IL-2 and IL-2R. Another mechanism of immunosuppression involving tumor necrosis factor/interferon γ-dependent nitric oxide production by inducible nitric oxide synthase was also described. Moreover, other studies showed that nitric oxide was produced by CD11b
+
Gr-1
+
MDSCs in the spleen, and later iNOS and arginase 1 expressed in CD11b
+
Ly6C
+
Ly6G
lo
monocytic MDSC were found in spleen and heart of
T. cruzi
infected mice that suppressed T cell proliferation. Uncontrolled expansion of monocytic MDSCs leads to L-arginine depletion which hinders nitric oxide production leading to death. Supplement of L-arginine partially reverts L-arginine depletion and survival, suggesting that L-arginine could be administered along with anti-parasitical drugs. On the other hand, pharmacological inhibition of MDSCs leads to death in mice, suggesting that some expansion of MDSCs is needed for an efficient immune response. The role of signaling molecules mediating immune suppression as reactive oxygen species, reactive nitrogen species, as well as prostaglandin E2, characteristics of MDSCs, in
T. cruzi
infection is not fully understood. We review and discuss the role of these reactive species mediators produced by MDSCs. Finally, we discuss the latest results that link the SLAMF1 immune receptor with reactive oxygen species. Interaction of the parasite with the SLAMF1 modulates parasite virulence through myeloid cell infectivity and reactive oxygen species production. We discuss the possible strategies for targeting MDSCs and SLAMF1 receptor in acute
Trypanosoma cruzi
infection in mice, to evaluate a possible translational application in human acute infections.
Chagas disease is a complex illness caused by the protozoan Trypanosoma cruzi displaying highly diverse clinical outcomes. In this sense, the genome sequence elucidation and comparison between ...strains may lead to disease understanding. Here, two new T. cruzi strains, have been sequenced, Y using Illumina and Bug2148 using PacBio, assembled, analyzed and compared with the T. cruzi annotated genomes available to date. The assembly stats from the new sequences show effective improvement of T. cruzi genome over the actual ones. Such as, the largest contig assembled (1.3 Mb in Bug2148) in de novo attempts and the highest mean assembly coverage (71X for Y). Our analysis reveals a new genomic expansion and greater complexity for those multi-copy gene families related to infection process and disease development, such as Trans-sialidases, Mucins and Mucin Associated Surface Proteins, among others. On one side, we demonstrate that multi-copy gene families are located near telomeric regions of the "chromosome-like" 1.3 Mb contig assembled of Bug2148, where they likely suffer high evolutive pressure. On the other hand, we identified several strain-specific single copy genes that might help to understand the differences in infectivity and physiology among strains. In summary, our results indicate that T. cruzi has a complex genomic architecture that may have promoted its evolution.
Chagas disease is a multisystemic disorder caused by the protozoan parasite
, which affects ~8 million people in Latin America, killing 7,000 people annually. Chagas disease is one of the main causes ...of death in the endemic area and the leading cause of infectious myocarditis in the world.
infection induces two phases, acute and chronic, where the infection is initially asymptomatic and the majority of patients will remain clinically indeterminate for life. However, over a period of 10-30 years, ~30% of infected individuals will develop irreversible, potentially fatal cardiac syndromes (chronic chagasic cardiomyopathy CCC), and/or dilatation of the gastro-intestinal tract (megacolon or megaesophagus). Myocarditis is the most serious and frequent manifestation of chronic Chagas heart disease and appears in about 30% of infected individuals several years after infection occurs. Myocarditis is characterized by a mononuclear cell infiltrate that includes different types of myeloid and lymphoid cells and it can occur also in the acute phase.
infects and replicates in macrophages and cardiomyocytes as well as in other nucleated cells. The pathogenesis of the chronic phase is thought to be dependent on an immune-inflammatory reaction to a low-grade replicative infection. It is known that cytokines produced by type 1 helper CD4+ T cells are able to control infection. However, the role that infiltrating lymphoid and myeloid cells may play in experimental and natural Chagas disease pathogenesis has not been completely elucidated, and several reports indicate that it depends on the mouse genetic background and parasite strain and/or inoculum. Here, we review the role that T cell CD4+ subsets, myeloid subclasses including myeloid-derived suppressor cells may play in the immunopathogenesis of Chagas disease with special focus on myocarditis, by comparing results obtained with different experimental animal models.
BACKGROUND: This study evaluated the efficacy of photochemical treatment (PCT) with amotosalen and ultraviolet A (UVA) light to inactivate Trypanosoma cruzi in contaminated platelet (PLT) components.
...STUDY DESIGN AND METHODS: Fifteen pools of buffy‐coat PLTs (BC‐PLTs) were inoculated with approximately 5 × 103 to 5 × 105 per mL of viable T. cruzi of the G, Tulahuen (T), or Y strains. Samples from BC‐PLTs were assayed for infectivity before and after PCT with 150 µmol per L amotosalen and 3 J per cm2 UVA light. Infectivity was determined with three different methods: 1) in vitro culture to detect viable epimastigotes, 2) 3Hthymidine incorporation in culture, and 3) in vivo inoculation into interferon‐γ receptor (IFN‐γR)‐deficient mice.
RESULTS: The in vitro assay yielded viable parasite titers of 3.9 × 105, 2.8 × 104, and 5.6 × 103 per mL (corresponding to 5.6, 4.4, and 3.8 logs/mL) for the Y, T, and G strains, respectively. PCT was able to inactivate all three strains of T. cruzi to below the limit of detection (10 parasites/mL) in the sensitive in vivo assay. Because 10‐mL samples, each concentrated into a 1‐mL sample for inoculation, were tested in the in vivo assay, log reductions achieved were greater than 5.6, greater than 4.4, and greater than 3.8 for the Y, T, and G strains of T. cruzi, respectively.
CONCLUSIONS: The pathogen reduction system with amotosalen HCl and UVA demonstrated robust efficacy for inactivation of high doses of three different strains of T. cruzi and offers the potential to make the PLT supply safer.
Chagas disease caused by the parasite Trypanosoma cruzi affects millions of people. Although its first genome dates from 2005, its complexity hindered a complete assembly and annotation. However, the ...new sequencing methods have improved genome annotation of some strains elucidating the broad genetic diversity and complexity of this parasite. Here, we reviewed the genomic structure and regulation, the genetic diversity, and the analysis of the principal multi-gene families of the recent genomes for several strains. The telomeric and sub-telomeric regions are sites with high recombination events, the genome displays two different compartments, the core and the disruptive, and the genome plasticity seems to play a key role in the survival and the infection process. Trypanosoma cruzi (T. cruzi) genome is composed mainly of multi-gene families as the trans-sialidases, mucins, and mucin-associated surface proteins. Trans-sialidases are the most abundant genes in the genome and show an important role in the effectiveness of the infection and the parasite survival. Mucins and MASPs are also important glycosylated proteins of the surface of the parasite that play a major biological role in both insect and mammal-dwelling stages. Altogether, these studies confirm the complexity of T. cruzi genome revealing relevant concepts to better understand Chagas disease.
Colorectal cancer (CRC) is a very common life‐threatening malignancy. Transcription factor‐like 5 (TCFL5) has been suggested to be involved in CRC. Here, we describe the expression of four ...alternative transcripts of TCFL5 and their relevance in CRC. Complete deletion of all isoforms drastically decreased pro‐tumoural properties such as spheroids formation and in vivo tumour growth, although increased migration in CRC cell lines. Overexpression of the two main isoforms, TCFL5_E8 and CHA, had opposite effects: TCFL5_E8 reduced proliferation and spheroids formation, while CHA increased them. TCFL5_E8 reduced in vivo tumour formation, while CHA had no effect. In addition, TCFL5_E8 and CHA have different roles in the regulation of the pluripotency‐related genes SOX2 and KLF4. Both isoforms bind directly to their promoters; however, TCFL5_E8 induced SOX2 and reduced KLF4 mRNA levels, whereas CHA did the opposite. Together, our results show that TCFL5 plays an important role in the development of CRC, being however isoform‐specific. This work also points to the need to analyse separately TCFL5 isoforms in cancer, due to their different and opposite functions.
In this study, the authors identify four isoforms of TCFL5 in colorectal cancer, each with strikingly different properties. Complete deletion of the TCFL5 locus reduced tumour cell proliferation and spheroid formation, but increased migration. However, whereas overexpression of the TCFL5_E8 isoform reduced proliferation and spheroid formation, overexpression of the CHA isoform increased them. In addition, CHA and TCFL5_E8 bound to the SOX2 and KLF4 promoters directly, controlling their transcription.
Chagas disease, caused by the parasite Trypanosoma cruzi, is one of the most neglected diseases in Latin America, being currently a global health problem. Its immunopathogenesis is still quite ...unknown. Moreover, there are important differences in pathogenicity between some different T. cruzi strains. For example, in mice, Y strain produces a high acute lethality while VFRA remains in the host mostly in a chronic manner.
Comparative proteomic studies between T. cruzi strains represent a complement for transcriptomics and may allow the detection of relevant factors or distinctive functions. Here for the first time, we compared the proteome of trypomastigotes from 2 strains, Y and VFRA, analyzed by mass spectrometry. Gene ontology analysis were used to display similarities or differences in cellular components, biological processes and molecular functions. Also, we performed metabolic pathways enrichment analysis to detect the most relevant pathways in each strain.
Although in general they have similar profiles in the different ontology groups, there were some particular interesting differences. Moreover, there were around 10% of different proteins between Y and VFRA strains, that were shared by other T. cruzi strains or protozoan species. They displayed many common enriched metabolic pathways but some others were uniquely enriched in one strain. Thus, we detected enriched antioxidant defenses in VFRA that could correlate with its ability to induce a chronic infection in mice controlling ROS production, while the Y strain revealed a great enrichment of pathways related with nucleotides and protein production, that could fit with its high parasite replication and lethality. In summary, Y and VFRA strains displayed comparable proteomes with some particular distinctions that could contribute to understand their different biological behaviors.
•Y and VFRA T. cruzi strains displayed up to a 10% of unique proteins in each one.•Both shared enriched pathways related with energy production and replication.•Y strain had unique enriched pathways related to nucleotide and protein production.•VFRA strain had unique enriched pathways related with antioxidant defenses.
Chagas disease, caused by the protozoan parasite Trypanosoma cruzi, affects several million people in Latin America. Myocarditis, observed during both the acute and chronic phases of the disease, is ...characterized by an inflammatory mononuclear cell infiltrate that includes CD4(+) T cells. It is known that Th1 cytokines help to control infection. The role that Treg and Th17 cells may play in disease outcome, however, has not been completely elucidated. We performed a comparative study of the dynamics of CD4(+) T cell subsets after infection with the T. cruzi Y strain during both the acute and chronic phases of the disease using susceptible BALB/c and non-susceptible C57BL/6 mice infected with high or low parasite inocula. During the acute phase, infected C57BL/6 mice showed high levels of CD4(+) T cell infiltration and expression of Th1 cytokines in the heart associated with the presence of Treg cells. In contrast, infected BALB/c mice had a high heart parasite burden, low heart CD4(+) T cell infiltration and low levels of Th1 and inflammatory cytokines, but with an increased presence of Th17 cells. Moreover, an increase in the expression of IL-6 in susceptible mice was associated with lethality upon infection with a high parasite load. Chronically infected BALB/c mice continued to present higher parasite burdens than C57BL/6 mice and also higher levels of IFN-γ, TNF, IL-10 and TGF-β. Thus, the regulation of the Th1 response by Treg cells in the acute phase may play a protective role in non-susceptible mice irrespective of parasite numbers. On the other hand, Th17 cells may protect susceptible mice at low levels of infection, but could, in association with IL-6, be pathogenic at high parasite loads.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The protozoan
resides in the oral cavity and is frequently observed in the periodontal pockets of humans and pets. This species of
is closely related to the human pathogen
, the agent of amoebiasis. ...Although
is highly enriched in people with periodontitis (a disease in which inflammation and bone loss correlate with changes in the microbial flora), the potential role of this protozoan in oral infectious diseases is not known. Periodontitis affects half the adult population in the world, eventually leads to edentulism, and has been linked to other pathologies, like diabetes and cardiovascular diseases. As aging is a risk factor for the disorder, it is considered an inevitable physiological process, even though it can be prevented and cured. However, the impact of periodontitis on the patient's health and quality of life, as well as its economic burden, are underestimated. Commonly accepted models explain the progression from health to gingivitis and then periodontitis by a gradual change in the identity and proportion of bacterial microorganisms in the gingival crevices. Though not pathognomonic, inflammation is always present in periodontitis. The recruitment of leukocytes to inflamed gums and their passage to the periodontal pocket lumen are speculated to fuel both tissue destruction and the development of the flora. The individual contribution to the disease of each bacterial species is difficult to establish and the eventual role of protozoa in the fate of this disease has been ignored. Following recent scientific findings, we discuss the relevance of these data and propose that the status of
be reconsidered as a potential pathogen contributing to periodontitis.
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