Persulfides (R−SSH) have been hypothesized as potent redox modulators and signaling compounds. Reported herein is the synthesis, characterization, and in vivo evaluation of a persulfide donor that ...releases N‐acetyl cysteine persulfide (NAC‐SSH) in response to the prokaryote‐specific enzyme nitroreductase. The donor, termed NDP‐NAC, decomposed in response to E. coli nitroreductase, resulting in release of NAC‐SSH. NDP‐NAC elicited gastroprotective effects in mice that were not observed in animals treated with control compounds incapable of persulfide release or in animals treated with Na2S. NDP‐NAC induced these effects by the upregulation of beneficial small‐ and medium‐chain fatty acids and through increasing growth of Turicibacter sanguinis, a beneficial gut bacterium. It also decreased the populations of Synergistales bacteria, opportunistic pathogens implicated in gastrointestinal infections. This study reveals the possibility of maintaining gut health or treating microbiome‐related diseases by the targeted delivery of reactive sulfur species.
The persulfide donor NDP‐NAC (see structure) was synthesized and found to decompose in response to E. coli nitroreductase with the release of N‐acetyl cysteine persulfide (NAC‐SSH). NDP‐NAC elicited gastroprotective effects in mice by the upregulation of beneficial small‐ and medium‐chain fatty acids, by increasing growth of Turicibacter sanguinis, a beneficial gut bacterium, and by decreasing populations of pathogenic Synergistales bacteria.
Immune system activation is essential to thwart the invasion of pathogens and respond appropriately to tissue damage. However, uncontrolled inflammation can result in extensive collateral damage ...underlying a diverse range of auto‐inflammatory, hyper‐inflammatory, and neoplastic diseases. The NF‐κB signaling pathway lies at the heart of the immune system and functions as a master regulator of gene transcription. Thus, this signaling cascade is heavily targeted by mechanisms designed to attenuate overzealous inflammation and promote resolution. Mechanisms associated with the negative regulation of NF‐κB signaling are currently under intense investigation and have yet to be fully elucidated. Here, we provide an overview of mechanisms that negatively regulate NF‐κB signaling through either attenuation of signal transduction, inhibition of posttranscriptional signaling, or interference with posttranslational modifications of key pathway components. While the regulators discussed for each group are far from comprehensive, they exemplify common mechanistic approaches that inhibit this critical biochemical signaling cascade. Despite their diversity, a commonality among these regulators is their selection of specific targets at key inflection points in the pathway, such as TNF‐receptor‐associated factor family members or essential kinases. A better understanding of these negative regulatory mechanisms will be essential to gain greater insight related to the maintenance of immune system homeostasis and inflammation resolution. These processes are vital elements of disease pathology and have important implications for targeted therapeutic strategies.
Review of regulators that negatively modulate NF‐κB signaling to attenuate inflammation and promote resolution.
Cancer drug delivery remains a formidable challenge due to systemic toxicity and inadequate extravascular transport of nanotherapeutics to cells distal from blood vessels. It is hypothesized that, in ...absence of an external driving force, the Salmonella enterica serovar Typhimurium could be exploited for autonomous targeted delivery of nanotherapeutics to currently unreachable sites. To test the hypothesis, a nanoscale bacteria‐enabled autonomous drug delivery system (NanoBEADS) is developed in which the functional capabilities of the tumor‐targeting S. Typhimurium VNP20009 are interfaced with poly(lactic‐co‐glycolic acid) nanoparticles. The impact of nanoparticle conjugation is evaluated on NanoBEADS' invasion of cancer cells and intratumoral transport in 3D tumor spheroids in vitro, and biodistribution in a mammary tumor model in vivo. It is found that intercellular (between cells) self‐replication and translocation are the dominant mechanisms of bacteria intratumoral penetration and that nanoparticle conjugation does not impede bacteria's intratumoral transport performance. Through the development of new transport metrics, it is demonstrated that NanoBEADS enhance nanoparticle retention and distribution in solid tumors by up to a remarkable 100‐fold without requiring any externally applied driving force or control input. Such autonomous biohybrid systems could unlock a powerful new paradigm in cancer treatment by improving the therapeutic index of chemotherapeutic drugs and minimizing systemic side effects.
Nanoscale bacteria‐enabled autonomous drug delivery system (NanoBEADS) agents are constructed by conjugating poly(lactic‐co‐glycolic acid) nanoparticles with tumor‐targeting Salmonella Typhimurium. NanoBEADS enhance retention and distribution of nanoparticles in solid tumors by up to a remarkable ≈100‐fold, through intercellular (between cells) self‐replication and translocation. This transport enhancement is achieved autonomously, without the need for any externally‐applied driving force or control input.
The clustered regularly interspaced short palindromic repeats (CRISPR) and Cas9 protein system is a revolutionary tool for gene therapy. Despite promising reports of the utility of CRISPR-Cas9 for in ...vivo gene editing, a principal problem in implementing this new process is delivery of high molecular weight DNA into cells.
Using poly(lactic-co-glycolic acid) (PLGA), a nanoparticle carrier was designed to deliver a model CRISPR-Cas9 plasmid into primary bone marrow derived macrophages. The engineered PLGA-based carriers were approximately 160 nm and fluorescently labeled by encapsulation of the fluorophore 6,13-bis(triisopropylsilylethynyl) pentacene (TIPS pentacene). An amine-end capped PLGA encapsulated 1.6 wt% DNA, with an encapsulation efficiency of 80%. Release studies revealed that most of the DNA was released within the first 24 h and corresponded to ~ 2-3 plasmid copies released per nanoparticle. In vitro experiments conducted with murine bone marrow derived macrophages demonstrated that after 24 h of treatment with the PLGA-encapsulated CRISPR plasmids, the majority of cells were positive for TIPS pentacene and the protein Cas9 was detectable within the cells.
In this work, plasmids for the CRISPR-Cas9 system were encapsulated in nanoparticles comprised of PLGA and were shown to induce expression of bacterial Cas9 in murine bone marrow derived macrophages in vitro. These results suggest that this nanoparticle-based plasmid delivery method can be effective for future in vivo applications of the CRISPR-Cas9 system.
B cell lymphoma-6 (Bcl-6) is a transcriptional repressor that is required for the differentiation of T follicular helper (T
) cell populations. Currently, the molecular mechanisms underlying the ...transcriptional regulation of Bcl-6 expression are unclear. In this study, we have identified the Ikaros zinc finger transcription factors Aiolos and Ikaros as novel regulators of Bcl-6. We found that increased expression of Bcl-6 in CD4
Th cell populations correlated with enhanced enrichment of Aiolos and Ikaros at the
promoter. Furthermore, overexpression of Aiolos or Ikaros, but not the related family member Eos, was sufficient to induce
promoter activity. Intriguingly, STAT3, a known Bcl-6 transcriptional regulator, physically interacted with Aiolos to form a transcription factor complex capable of inducing the expression of
and the T
-associated cytokine receptor
Importantly, in vivo studies revealed that the expression of Aiolos was elevated in Ag-specific T
cells compared with that observed in non-T
effector Th cells generated in response to influenza infection. Collectively, these data describe a novel regulatory mechanism through which STAT3 and the Ikaros zinc finger transcription factors Aiolos and Ikaros cooperate to regulate Bcl-6 expression.
Despite promising treatments for breast cancer, mortality rates remain high and treatments for metastatic disease are limited. High-frequency irreversible electroporation (H-FIRE) is a novel tumor ...ablation technique that utilizes high-frequency bipolar electric pulses to destabilize cancer cell membranes and induce cell death. However, there is currently a paucity of data pertaining to immune system activation following H-FIRE and other electroporation based tumor ablation techniques.
Here, we utilized the mouse 4T1 mammary tumor model to evaluate H-FIRE treatment parameters on cancer progression and immune system activation in vitro and in vivo.
H-FIRE effectively ablates the primary tumor and induces a pro-inflammatory shift in the tumor microenvironment. We further show that local treatment with H-FIRE significantly reduces 4T1 metastases. H-FIRE kills 4T1 cells through non-thermal mechanisms associated with necrosis and pyroptosis resulting in damage associated molecular pattern signaling in vitro and in vivo. Our data indicate that the level of tumor ablation correlates with increased activation of cellular immunity. Likewise, we show that the decrease in metastatic lesions is dependent on the intact immune system and H-FIRE generates 4T1 neoantigens that engage the adaptive immune system to significantly attenuate tumor progression.
Cell death and tumor ablation following H-FIRE treatment activates the local innate immune system, which shifts the tumor microenvironment from an anti-inflammatory state to a pro-inflammatory state. The non-thermal damage to the cancer cells and increased innate immune system stimulation improves antigen presentation, resulting in the engagement of the adaptive immune system and improved systemic anti-tumor immunity.
From immunology to neuroscience, interactions between the microbiome and host are increasingly appreciated as potent drivers of health and disease. Epidemiological studies previously identified ...compelling correlations between perinatal microbiome insults and neurobehavioral outcomes, the mechanistic details of which are just beginning to take shape thanks to germ-free and antibiotics-based animal models. This review summarizes parallel developments from clinical and preclinical research that suggest neuroactive roles for gut bacteria and their metabolites. We also examine the nascent field of microbiome-microglia crosstalk research, which includes pharmacological and genetic strategies to inform functional capabilities of microglia in response to microbial programming. Finally, we address an emerging hypothesis behind neurodevelopmental disorders, which implicates microbiome dysbiosis in the atypical programming of neuroimmune cells, namely microglia.
The NLRP1 inflammasome attenuates inflammatory bowel disease (IBD) progression and colitis-associated tumorigenesis. A possible mechanism postulates that the lack of the NLRP1 inflammasome creates ...permissive niches in the gut for pathogenic bacteria to flourish, causing dysbiosis and increased IBD susceptibility. To evaluate this hypothesis, we characterized the gut microbiome of wild-type, Nlrp1b–/–, and Asc–/– mice under naïve conditions by sequencing the V3 region of the 16s rRNA gene. For both genetically modified mouse lines, the microbiome composition reflected overrepresentation of bacteria associated with dysbiosis relative to wild-type animals. Measurement of short- and medium-chain fatty acids by mass spectrometry further revealed significant differences between genotypes. However, prior to concluding that the NLRP1 inflammasome plays a role in regulating the composition of the microbiome, we evaluated two additional strategies for cohousing wild-type and Nlrp1b–/– mice: breeding homozygous parents and cohousing at weaning, and breeding from heterozygous parents and cohousing littermates. We found that maternal influence was the greater predictor of microbiome composition rather than genotype. With the rise in microbiome research across disciplines, our study should be viewed as a cautionary example that illustrates the importance of careful breeding and housing strategies when evaluating host-microbiome interactions.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
New methods of tumor ablation have shown exciting efficacy in pre-clinical models but often demonstrate limited success in the clinic. Due to a lack of quality or quantity in primary malignant tissue ...specimens, therapeutic development and optimization studies are typically conducted on healthy tissue or cell-line derived rodent tumors that don't allow for high resolution modeling of mechanical, chemical, and biological properties. These surrogates do not accurately recapitulate many critical components of the tumor microenvironment that can impact
in situ
treatment success. Here, we propose utilizing patient-derived xenograft (PDX) models to propagate clinically relevant tumor specimens for the optimization and development of novel tumor ablation modalities. Specimens from three individual pancreatic ductal adenocarcinoma (PDAC) patients were utilized to generate PDX models. This process generated 15–18 tumors that were allowed to expand to 1.5 cm in diameter over the course of 50–70 days. The PDX tumors were morphologically and pathologically identical to primary tumor tissue. Likewise, the PDX tumors were also found to be physiologically superior to other
in vitro
and
ex vivo
models based on immortalized cell lines. We utilized the PDX tumors to refine and optimize irreversible electroporation (IRE) treatment parameters. IRE, a novel, non-thermal tumor ablation modality, is being evaluated in a diverse range of cancer clinical trials including pancreatic cancer. The PDX tumors were compared against either Pan02 mouse derived tumors or resected tissue from human PDAC patients. The PDX tumors demonstrated similar changes in electrical conductivity and Joule heating following IRE treatment. Computational modeling revealed a high similarity in the predicted ablation size of the PDX tumors that closely correlate with the data generated with the primary human pancreatic tumor tissue. Gene expression analysis revealed that IRE treatment resulted in an increase in biological pathway signaling associated with interferon gamma signaling, necrosis and mitochondria dysfunction, suggesting potential co-therapy targets. Together, these findings highlight the utility of the PDX system in tumor ablation modeling for IRE and increasing clinical application efficacy. It is also feasible that the use of PDX models will significantly benefit other ablation modality testing beyond IRE.
Recent advances have revealed significant insight into inflammatory bowel disease (IBD) pathobiology. Ulcerative colitis and Crohn's disease, the chronic relapsing clinical manifestations of IBD, are ...complex disorders with genetic and environmental influences. These diseases are associated with the dysregulation of immune tolerance, excessive inflammation, and damage to the epithelial cell barrier. Increasing evidence indicates that pattern recognition receptors, including Toll-like receptors (TLRs) and nucleotide-binding domain and leucine-rich repeat-containing proteins (NLRs), function to maintain immune system homeostasis, modulate the gastrointestinal microbiome, and promote proper intestinal epithelial cell regeneration and repair. New insights have revealed that NLR family members are essential components in maintaining this immune system homeostasis. To date, the vast majority of studies associated with NLRs have focused on family members that form a multiprotein signaling platform called the inflammasome. These signaling complexes are responsible for the cleavage and activation of the potent pleotropic cytokines IL-1β and IL-18, and they facilitate a unique form of cell death defined as pyroptosis. In this review, we summarize the current paradigms associated with NLR inflammasome maintenance of immune system homeostasis in the gastrointestinal system. New concepts related to canonical and noncanonical inflammasome signaling, as well as the implications of classical and alternative inflammasomes in IBD pathogenesis, are also reviewed.
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