The ongoing COVID-19 pandemic has revealed the shortfalls in our understanding of how to treat coronavirus infections. With almost 7 million case fatalities of COVID-19 globally, the catalog of FDA-approved antiviral therapeutics is limited compared to other medications, such as antibiotics. All-trans retinoic acid (RA), or activated vitamin A, has been studied as a potential therapeutic against coronavirus infection because of its antiviral properties.
View Article and Find Full Text PDFSepsis is among the most dangerous known diseases, resulting from the dysregulation of the innate immune system in a process that is characterized largely by proinflammatory cytokines. It manifests as an excessive immune response to a pathogen and often leads to life-threatening complications such as shock and multiple-organ failure. Within the past several decades, much progress has been made to better understand the pathophysiology of sepsis and improve treatment.
View Article and Find Full Text PDFThe type-I interferon (IFN) system represents the first line of defense against viral pathogens. Recognition of the virus initiates complex signaling pathways that result in the transcriptional induction of IFNs, which are then secreted. Secreted IFNs stimulate nearby cells and result in the production of numerous proinflammatory cytokines and antiviral factors.
View Article and Find Full Text PDFPreviously characterized as a purely immune mediated disease, sepsis is now recognized as a dysregulated multisystem response against a pathogen. Recognition of the infectious agent by pathogen recognition receptors (PRRs) can initiate activation of the NF-κB signaling pathway and promote the secretion of proinflammatory cytokines. During sepsis, the activation of NF-κB is dysregulated and results in cytokine storm, or the pathologic release of cytokines.
View Article and Find Full Text PDFDominant infiltration of neutrophils is a hallmark of many inflammatory diseases, especially in septic shock. IL-1β as one of the most early released proinflammatory cytokine in neutrophil, plays a pivotal role in the progress of sepsis. In this study, we built a high-throughput-compatible drug screen assay platform based on our newly constructed reporter C57BL/6 mice, pIL1-DsRed, expressing the DsRed gene under the control of the IL-1β promoter.
View Article and Find Full Text PDFHyperinflammatory response caused by infections such as Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) increases organ failure, intensive care unit admission, and mortality. Cytokine storm in patients with Coronavirus Disease 2019 (COVID-19) drives this pattern of poor clinical outcomes and is dependent upon the activity of the transcription factor complex nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kappaB) and its downstream target gene interleukin 6 (IL6) which interacts with IL6 receptor (IL6R) and the IL6 signal transduction protein (IL6ST or gp130) to regulate intracellular inflammatory pathways. In this study, we compare transcriptomic signatures from a variety of drug-treated or genetically suppressed (i.
View Article and Find Full Text PDFSepsis is typically triggered by an overwhelming systemic inflammatory response to pathogens, and may lead to severe organ dysfunction and/or death. Sepsis consequently has a high mortality rate and a high rate of complications for survivors, despite modern medical advances. Therefore, drug identification and validation for the treatment of sepsis is of the utmost importance.
View Article and Find Full Text PDFPathogenic sepsis is not a monolithic condition. Three major types of sepsis exist within this category: bacterial, viral, and fungal, each with its own mechanism of action. While similar in symptoms, the etiologies and immune mechanisms of these types differ enough that a discrete patient base can be recognized for each one.
View Article and Find Full Text PDFSepsis, which kills over 200,000 patients and costs over $20 billion in the United States alone, presents a constant but preventable challenge in the healthcare system. Among the more challenging problems that it presents is misdiagnosis due to conflation with other inflammatory processes, as its mechanisms are identical to those of other inflammatory states. Unfortunately, current biomarker tests can only assess the severity and mortality risk of each case, whereas no single test exists that can predict sepsis prior to the onset of symptoms for the purpose of pre-emptive care and monitoring.
View Article and Find Full Text PDFMAP phosphatases (MKP)-1 acts as an important regulator of innate immune response through a mechanism of control and attention both MAPK and NF-κB molecules during bacterial infection. However, the regulatory role of MKP-1 in the interplay between MAPK and NFκB pathway molecules is still not fully understood. In present study, we showed a direct interactions of p38, ERK or IκBα with MKP-1, and demonstrated that MKP-1 was a pivotal feedback control for both MAP kinases and NF-κB pathway in response to S.
View Article and Find Full Text PDFThe importance of microRNAs (miRNAs) in biological and disease processes necessitates a better understanding of the mechanisms that regulate miRNA abundance. We showed that the activities of the mitogen-activated protein kinase (MAPK) p38 and its downstream effector kinase MAPK-activated protein kinase 2 (MK2) were necessary for the efficient processing of a subset of primary miRNAs (pri-miRNAs). Through yeast two-hybrid screening, we identified p68 (also known as DDX5), a key component of the Drosha complex that processes pri-miRNAs, as an MK2-interacting protein, and we found that MK2 phosphorylated p68 at Ser(197) in cells.
View Article and Find Full Text PDFHOXC8 expression is upregulated in diverse cancer types, and a high level of HOXC8 is often associated with the aggressive/metastatic phenotypes. We previously reported that the presence of HOXC8 is essential for breast cancer cell migration and metastasis. However, the underlying molecular mechanism of HOXC8 regulation of cell migration is unclear.
View Article and Find Full Text PDFBackground: Inflammation is a hallmark of many serious human diseases. Nontypeable Haemophilus influenzae (NTHi) is an important human pathogen causing respiratory tract infections in both adults and children. NTHi infections are characterized by inflammation, which is mainly mediated by nuclear transcription factor-kappa B (NF-κB)-dependent production of proinflammatory mediators.
View Article and Find Full Text PDFGlobal mature microRNA (miRNA) expression is downregulated in cancers, and impaired miRNA processing enhances cancer cell proliferation. These findings indicate that the miRNA system generally serves as a negative regulator during cancer progression. In this study, we investigated the role of the miRNA system in cancer cell invasion by determining the effect of damaging miRNA processing on invasion-essential urokinase-type plasminogen activator (uPA) expression in breast cancer cells.
View Article and Find Full Text PDFIn the host immune system, the leukocytes are often exposed to multiple pathogens including bacteria and viruses. The principal challenge for the host is to efficiently detect the invading pathogen and mount a rapid defensive response. Leukocytes recognize invading pathogens by directly interacting with pathogen-associated molecular patterns via Toll-like receptors (TLRs) expressed on the leukocyte surfaces.
View Article and Find Full Text PDFStimulation of phagocytic leukocytes with bacterial chemoattractant resulted in the release of matrix metal-loproteinases (MMPs). Little is known about the mechanisms of bacterial chemoattractant regulation of MMP in phagocytic leukocytes. We report here that the mechanisms of the bacterial chemotactic peptidefMLP-induced MMP -9 release in monocytes appeared to be different from fMLP-stimulated MMP-9 release in neutrophils.
View Article and Find Full Text PDFOvarian cancer is mainly confined in peritoneal cavity and its metastasis is often associated with the formation of malignant ascites. As lysophosphatidic acid (LPA) is present at high levels in ascites of ovarian cancer patients and potently stimulates cell migration, we reason that LPA-stimulated cell migration may play an important role in ovarian cancer metastasis. Here, we show that only ovarian cancer cell lines with LPA migratory response undergo peritoneal metastatic colonization.
View Article and Find Full Text PDFIn the host immune system, leukocytes are often exposed to multiple inflammation inducers. NF-κB is of considerable importance in leukocyte function because of its ability to activate the transcription of many proinflammatory immediate-early genes. Tremendous efforts have been made toward understanding how NF-κB is activated by various inducers.
View Article and Find Full Text PDFCell migration is a critical step in cancer cell invasion. Recent studies have implicated the importance of the extracellular signal-regulated kinase (ERK) signaling pathway in cancer cell migration. However, the mechanism associated with ERK-regulated cell migration is poorly understood.
View Article and Find Full Text PDFPerniosis (chilblains) is a vasospastic, inflammatory disease that occurs when the skin is subjected to cold above the freezing point, under damp conditions. Erythematous (violaceous) blisters, ulcerations or pustules that sit on an edematous base, accompanied by pain, burning or itching, are usually evident. To the inexperienced clinician it may resemble community-associated methicillin-resistant Staphylococcus aureus and could lead to inappropriate treatment.
View Article and Find Full Text PDFGram-negative bacterial lipopolysaccharide (LPS) activates macrophages by interacting with Toll-like receptor 4 (TLR4) and triggers the production of various pro-inflammatory Th1 type (type 1) cytokines such as IFNgamma, TNFalpha, and IL8. Though some recent studies cited macrophages as potential sources for Th2 type (type 2) cytokines, little however is known about the intracellular events that lead to LPS-induced type 2 cytokines in macrophages. To understand the mechanisms by which LPS induces type 2 cytokine gene expression, macrophages were stimulated with LPS, and the expression of IL-4 and IL-5 genes were examined.
View Article and Find Full Text PDFEndocr Metab Immune Disord Drug Targets
December 2009
Accumulating evidence demonstrates that bacterial chemoattractants not only attract leukocytes (chemotaxis) but also contribute directly to inflammation by activation of leukocytes to produce a variety of pro-inflammatory cytokines. Recent studies have shown that mixtures of the bacterial chemoattractant fMLP (N-formyl-Met-Leu-Phe) and other bacterial products/components such as LPS (lipopolysaccharide) behave synergistically in activating leukocytes. These results suggest that inflammatory responses are induced by multiple inducers that operate synergistically through multiple signaling pathways.
View Article and Find Full Text PDFA wide variety of stimuli have been shown to induce inflammation, but bacteria products/components are considered the major inducers during bacterial infections. We previously demonstrated that bacterial products/components such as LPS, a glycolipid component of the bacterial outer membrane, and formylated peptides (fMLP), a bacterial-derived peptide, induced proinflammatory cytokine gene expression in human peripheral blood monocytes. We now present evidence that mixtures of bacterial products/components LPS and fMLP behave synergistically in the induction of inflammation in vitro and in vivo.
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