Dynamics of Prolyl Hydroxylases Levels During Disease Progression in Experimental Colitis

Expression of HIF1α in intestinal epithelium restricts arthritis inflammation by inhibiting RIPK3-induced cell death machinery

OBJECTIVES

To investigate the mechanism by which intestinal epithelial cell (IEC) death induces arthritis.

METHODS

IEC death was assessed by staining for necroptosis and apoptosis markers and fluorescence in situ hybridisation at different time points during collagen-induced arthritis (CIA). During the development of CIA, messenger RNA (mRNA) sequencing was performed, followed by Gene Ontology enrichment analysis of differentially expressed genes. Mice deficient for hypoxia-inducible factor 1α (Hif1a) in IECs (Hif1a ∆IEC) were generated and induced for arthritis. mRNA sequencing, chromatin immunoprecipitated (ChIP) DNA sequencing and ChIP-qualitative PCR were performed on IECs from Hif1a ∆IEC mice and littermate controls. Effects of HIF1α stabilisation by inhibition of prolyl hydroxylase domain-containing enzymes and treatment with the inhibitor of receptor-interacting protein kinase-3 (RIPK3) were tested in intestinal organoids and in CIA.

RESULTS

IEC underwent apoptotic and necroptotic cell death at the onset of arthritis, leading to impaired gut barrier function. HIF1α was identified as one of the most upregulated genes in IECs during the onset of arthritis. Deletion of Hif1a in IEC enhanced IEC necroptosis, triggered intestinal inflammation and exacerbated arthritis. HIF1α was found to be a key transcriptional repressor for the necroptosis-inducing factor RIPK3. Enhanced RIPK3 expression, indicating necroptosis, was also found in the intestinal epithelium of patients with new-onset rheumatoid arthritis. Therapeutic stabilisation of HIF1α as well as small-molecule-based RIPK3 inhibition rescued intestinal necroptosis in vitro and in vivo and suppressed the development of arthritis.

CONCLUSION

Our results identify IEC necroptosis as a critical link between the gut and the development of arthritis.

Prevalence and Association between Primary Stability and Bone Quality in Implants Placed in Edentulous Dental Arches: A Retrospective Analysis

Immediate function has become an accepted treatment modality for fixed restorations in completely edentulous jaws. The dental implants have gained immense popularity. A secure implant primary stability is positively associated with a successful implant integration and long term successful clinical outcome. The main aim of this study was to find the association between primary stability and bone density in implants placed in maxilla and mandible. A total of 1263 patients who had undergone implant placement from March 2020-March 2021 in Saveetha Dental College and Hospitals, Chennai, India were chosen for the study. The primary stability and bone density of these patients were collected from the hospital records. The collected data was compiled, reviewed, tabulated in Microsoft Excel sheet and entered in SPSS software for statistical analysis. In the present study, the patient aged between 28 and 37 years had undergone more implant placement (31%) with male predilection (53%). The most commonly associated primary stability was found to be 30-40 Ncm (51.37%) predominantly with D2 type of bone density (52.69%). A Chi-squared statistical test was done for primary stability and bone density and the P was found to be 0.00 (Chi-squared P < 0.05, statistically significant). The most predominant bone density was D2 associated with primary stability of 30-40 Ncm. The association between bone density and primary stability was found to be statistically significant. The present study shows a strong relationship between bone density and primary implant stability.

T-scans in implant procedures

T scans are a breakthrough in technology which allows the user to accurately analyze the occlusion of a patient with minimal to zero errors. They are used during prosthodontic rehabilitation to map out the patient's occlusion to plan for replacements. Such a high advancement in technology has a backdraw. The cost of the equipment is a concern for simple dental practitioners. There are no large scale studies using T scans in determining the occlusion. Therefore, it is of interest to analyze the use of T scans in determining the percentage of contact in patients with dental implants. This retrospective analysis was done at the Saveetha University hospital set up where patients undergoing prosthesis fabrication for implants were included. Details like their age, gender and the percentage of contact of the implant and percentage of contact on the adjacent tooth were recorded. These details were tabulated and imported to IBM SPSS version 23 for statistical analysis. Chi square test was used to analyze comparable variables. 22 patients were analyzed, the mean percentage of contact of implants was found to be 7.45±;9.01 and the mean percentage of contact of adjacent teeth was found to be 10.14±6.7. Thus, T scan is an efficient method in recording the dynamic occlusal contacts of a patient. The use of T scan reveals data pertaining to individual tooth but in the present study there is no statistical significance in terms of exact values comparing implant contact to adjacent tooth contact. Further studies are needed with relation to timing and contact surface of implant prosthesis.

Gold nanoparticles-embedded ceria with enhanced antioxidant activities for treating inflammatory bowel disease

The excessive reactive oxygen species (ROS) is a hallmark associated with the initiation and progression of inflammatory bowel disease (IBD), which execrably form a vicious cycle of ROS and inflammation to continually promote disease progression. Here, the gold nanoparticles-embedded ceria nanoparticles (Au/CeO₂) with enhanced antioxidant activities are designed to block this cycle reaction for treating IBD by scavenging overproduced ROS. The Au/CeO₂ with core-shell and porous structure exhibits significantly higher enzymatic catalytic activities compared with commercial ceria nanoparticles, likely due to the effective exposure of catalytic sites, higher content of Ce (III) and oxygen vacancy, and accelerated reduction from Ce (IV) to Ce (III). Being coated with negatively-charged hyaluronic acid, the Au/CeO₂@HA facilitates accumulation in inflamed colon tissues via oral administration, reduces pro-inflammatory cytokines, and effectively alleviates colon injury in colitis mice. Overall, the Au/CeO₂@HA with good biocompatibility is a promising nano-therapeutic for treating IBD.

Personalized redox medicine in inflammatory bowel diseases: an emerging role for HIF-1α and NRF2 as therapeutic targets

Inflammatory bowel diseases (IBD), encompassing Crohn's disease (CD) and ulcerative colitis (UC), are intimately associated with inflammation and overproduction of reactive oxygen species (ROS). Temporal and inter-individual variabilities in disease activity and response to therapy pose significant challenges to diagnosis and patient care. Discovery and validation of truly integrative biomarkers would benefit from embracing redox metabolomics approaches with prioritization of central regulatory hubs. We here make a case for applying a personalized redox medicine approach that aims to selectively inhibit pathological overproduction and/or altered expression of specific enzymatic sources of ROS without compromising physiological function. To this end, improved 'clinical-omics integration' may help to better understand which particular redox signaling pathways are disrupted in what patient. Pharmacological interventions capable of activating endogenous antioxidant defense systems may represent viable therapeutic options to restore local/systemic redox status, with HIF-1α and NRF2 holding particular promise in this context. Achieving the implementation of clinically meaningful mechanism-based biomarkers requires development of easy-to-use, robust and cost-effective tools for secure diagnosis and monitoring of treatment efficacy. Ultimately, matching redox-directed pharmacological interventions to individual patient phenotypes using predictive biomarkers may offer new opportunities to break the therapeutic ceiling in IBD.

BRD4 Protein as a Target for Lung Cancer and Hematological Cancer Therapy: A Review

The BET protein family plays a crucial role in regulating the epigenetic landscape of the genome. Their role in regulating tumor-related gene expression and its impact on the survival of tumor cells is widely acknowledged. Among the BET family constituents, BRD4 is a significant protein. It is a bromodomain-containing protein located at the outer terminal that recognizes histones that have undergone acetylation. It is present in the promoter or enhancer region of the target gene and is responsible for initiating and sustaining the expression of genes associated with tumorigenesis. BRD4 expression is significantly elevated in various tumor types. Research has indicated that BRD4 plays a significant role in regulating various transcription factors and chromatin modification, as well as in repairing DNA damage and preserving telomere function, ultimately contributing to the survival of cancerous cells. The protein BRD4 has a significant impact on antitumor therapy, particularly in the management of lung cancer and hematological malignancies, and the promising potential of BRD4 inhibitors in the realm of cancer prevention and treatment is a topic of great interest. Therefore, BRD4 is considered a promising candidate for prophylaxis and therapy of neoplastic diseases. However, further research is required to fully comprehend the significance and indispensability of BRD4 in cancer and its potential as a therapeutic target.

Hypoxia inducible factor prolyl hydroxylases in inflammatory bowel disease

Inflammatory bowel disease (IBD) is a chronic disease that is characterized by intestinal inflammation. Epithelial damage and loss of intestinal barrier function are believed to be the hallmark pathologies of the disease. In IBD, the resident and infiltrating immune cells consume much oxygen, rendering the inflamed intestinal mucosa hypoxic. In hypoxia, the hypoxia-inducible factor (HIF) is induced to cope with the lack of oxygen and protect intestinal barrier. Protein stability of HIF is tightly controlled by prolyl hydroxylases (PHDs). Stabilization of HIF through inhibition of PHDs is appearing as a new strategy of IBD treatment. Studies have shown that PHD-targeting is beneficial to the treatment of IBD. In this Review, we summarize the current understanding of the role of HIF and PHDs in IBD and discuss the therapeutic potential of targeting PHD-HIF pathway for IBD treatment.

Effect of brushing simulation on the surface roughness of soft-tissue liners: An in vitro study

Soft denture liners evenly distribute functional loads over denture-bearing tissues. The liners aid in more evenly distributing the pressures of mastication to the underlying tissues by absorbing some of the masticatory forces. The study aimed to evaluate the brushing simulation influence on the surface roughness property of soft-tissue liners. A total of eight samples of Avue brand soft-tissue liners with the composition of varnish base and varnish catalyst were suspended into a standard template extracted and numbered sequentially and surface roughness was calculated using a stylus profilometer. A total of 30,000 cycles brushing were done, where the first group samples were brushed with Colgate toothpaste and the second group brushed with Dabur Red toothpaste using a toothbrush simulator (ZM3.8 SD Mechatronik). The data of both pre- and postbrushing values were recorded manually and statistically uploaded on SPSS software version 22 and values were represented in clustered bar graph forms. The significance value of Ra was 0.321. The significance value of Rq was 0.211. The significance value of Rz was 0.354, hence statistically, insignificant. In the present study, the surface roughness of soft-tissue liners is reduced to a minimal extent after brushing simulation.

Neutrophil-Epithelial Crosstalk During Intestinal Inflammation

Neutrophils are the most abundant leukocyte population in the human circulatory system and are rapidly recruited to sites of inflammation. Neutrophils play a multifaceted role in intestinal inflammation, as they contribute to the elimination of invading pathogens. Recently, their role in epithelial restitution has been widely recognized; however, they are also associated with bystander tissue damage. The intestinal epithelium provides a physical barrier to prevent direct contact of luminal contents with subepithelial tissues, which is extremely important for the maintenance of intestinal homeostasis. Numerous studies have demonstrated that transepithelial migration of neutrophils is closely related to disease symptoms and disruption of crypt architecture in inflammatory bowel disease and experimental colitis. There has been growing interest in how neutrophils interact with the epithelium under inflammatory conditions. Most studies focus on the effects of neutrophils on intestinal epithelial cells; however, the effects of intestinal epithelial cells on neutrophils during intestinal inflammation need to be well-established. Based on these data, we have summarized recent articles on the role of neutrophil-epithelial interactions in intestinal inflammation, particularly highlighting the epithelium-derived molecular regulators that mediate neutrophil recruitment, transepithelial migration, and detachment from the epithelium, as well as the functional consequences of their crosstalk. A better understanding of these molecular events may help develop novel therapeutic targets for mitigating the deleterious effects of neutrophils in inflammatory bowel disease.

Post-Translational Modifications of BRD4: Therapeutic Targets for Tumor

Bromodomain-containing protein 4 (BRD4), a member of the bromodomain and extraterminal (BET) family, is considered to be a major driver of cancer cell growth and a new target for cancer therapy. Over 30 targeted inhibitors currently in preclinical and clinical trials have significant inhibitory effects on various tumors, including acute myelogenous leukemia (AML), diffuse large B cell lymphoma, prostate cancer, breast cancer and so on. However, resistance frequently occurs, revealing the limitations of BET inhibitor (BETi) therapy and the complexity of the BRD4 expression mechanism and action pathway. Current studies believe that when the internal and external environmental conditions of cells change, tumor cells can directly modify proteins by posttranslational modifications (PTMs) without changing the original DNA sequence to change their functions, and epigenetic modifications can also be activated to form new heritable phenotypes in response to various environmental stresses. In fact, research is constantly being supplemented with regards to that the regulatory role of BRD4 in tumors is closely related to PTMs. At present, the PTMs of BRD4 mainly include ubiquitination and phosphorylation; the former mainly regulates the stability of the BRD4 protein and mediates BETi resistance, while the latter is related to the biological functions of BRD4, such as transcriptional regulation, cofactor recruitment, chromatin binding and so on. At the same time, other PTMs, such as hydroxylation, acetylation and methylation, also play various roles in BRD4 regulation. The diversity, complexity and reversibility of posttranslational modifications affect the structure, stability and biological function of the BRD4 protein and participate in the occurrence and development of tumors by regulating the expression of tumor-related genes and even become the core and undeniable mechanism. Therefore, targeting BRD4-related modification sites or enzymes may be an effective strategy for cancer prevention and treatment. This review summarizes the role of different BRD4 modification types, elucidates the pathogenesis in the corresponding cancers, provides a theoretical reference for identifying new targets and effective combination therapy strategies, and discusses the opportunities, barriers, and limitations of PTM-based therapies for future cancer treatment.

Hypoxia-Inducible Factor (HIF): Fuel for Cancer Progression

Hypoxia is an integral part of the tumor microenvironment, caused primarily due to rapidly multiplying tumor cells and a lack of proper blood supply. Among the major hypoxic pathways, HIF-1 transcription factor activation is one of the widely investigated pathways in the hypoxic tumor microenvironment (TME). HIF-1 is known to activate several adaptive reactions in response to oxygen deficiency in tumor cells. HIF-1 has two subunits, HIF-1β (constitutive) and HIF-1α (inducible). The HIF-1α expression is largely regulated via various cytokines (through PI3K-ACT-mTOR signals), which involves the cascading of several growth factors and oncogenic cascades. These events lead to the loss of cellular tumor suppressant activity through changes in the level of oxygen via oxygen-dependent and oxygen-independent pathways. The significant and crucial role of HIF in cancer progression and its underlying mechanisms have gained much attention lately among the translational researchers in the fields of cancer and biological sciences, which have enabled them to correlate these mechanisms with various other disease modalities. In the present review, we have summarized the key findings related to the role of HIF in the progression of tumors.

Tambuwala M. Dietary Crocin is Protective in Pancreatic Cancer while Reducing Radiation-Induced Hepatic Oxidative Damage

Pancreatic cancer is one of the fatal causes of global cancer-related deaths. Although surgery and chemotherapy are standard treatment options, post-treatment outcomes often end in a poor prognosis. In the present study, we investigated anti-pancreatic cancer and amelioration of radiation-induced oxidative damage by crocin. Crocin is a carotenoid isolated from the dietary herb saffron, a prospect for novel leads as an anti-cancer agent. Crocin significantly reduced cell viability of BXPC3 and Capan-2 by triggering caspase signaling via the downregulation of Bcl-2. It modulated the expression of cell cycle signaling proteins P53, P21, P27, CDK2, c-MYC, Cyt-c and P38. Concomitantly, crocin treatment-induced apoptosis by inducing the release of cytochrome c from mitochondria to cytosol. Microarray analysis of the expression signature of genes induced by crocin showed a substantial number of genes involved in cell signaling pathways and checkpoints (723) are significantly affected by crocin. In mice bearing pancreatic tumors, crocin significantly reduced tumor burden without a change in body weight. Additionally, it showed significant protection against radiation-induced hepatic oxidative damage, reduced the levels of hepatic toxicity and preserved liver morphology. These findings indicate that crocin has a potential role in the treatment, prevention and management of pancreatic cancer.

The potential of dendrimer in delivery of therapeutics for dentistry

Dendrimers are hyperbranched nanoparticle structures along with its surface modifications can to be used in dental biomaterials for biomimetic remineralisation of enamel and dentin. The review highlights the therapeutic applications of dendrimers in the field of dentistry. It addresses the possible mechanisms of enhancement of mechanical properties of adhesives and resins structure. Dendrimers due to its unique construction of possessing inner hydrophobic and outer hydrophilic structure can act as drug carrier for delivery of antimicrobial drugs for treatment of periodontal diseases and at peripheral dental implant areas. Dendrimers due to its hyperbranched structures can provides a unique drug delivery vehicle for delivery of a drug at specific site for sustained release for therapeutic effects. Thus, dendrimers can be one of the most important constituents which can be incorporated in dental biomaterials for better outcomes in dentistry.