TRAF2 exerts opposing effects on basal and TNFα-induced activation of the classic IKK complex in hematopoietic cells in mice

Molecular signatures in prion disease: altered death receptor pathways in a mouse model

BACKGROUND

Prion diseases are transmissible and fatal neurodegenerative diseases characterized by accumulation of misfolded prion protein isoform (PrPSc), astrocytosis, microgliosis, spongiosis, and neurodegeneration. Elevated levels of cell membrane associated PrPSc protein and inflammatory cytokines hint towards the activation of death receptor (DR) pathway/s in prion diseases. Activation of DRs regulate, either cell survival or apoptosis, autophagy and necroptosis based on the adaptors they interact. Very little is known about the DR pathways activation in prion disease. DR3 and DR5 that are expressed in normal mouse brain were never studied in prion disease, so also their ligands and any DR adaptors. This research gap is notable and investigated in the present study.

METHODS

C57BL/6J mice were infected with Rocky Mountain Laboratory scrapie mouse prion strain. The progression of prion disease was examined by observing morphological and behavioural abnormalities. The levels of PrP isoforms and GFAP were measured as the marker of PrPSc accumulation and astrocytosis respectively using antibody-based techniques that detect proteins on blot and brain section. The levels of DRs, their glycosylation and ectodomain shedding, and associated factors warrant their examination at protein level, hence western blot analysis was employed in this study.

RESULTS

Prion-infected mice developed motor deficits and neuropathology like PrPSc accumulation and astrocytosis similar to other prion diseases. Results from this research show higher expression of all DR ligands, TNFR1, Fas and p75NTR but decreased levels DR3 and DR5. The levels of DR adaptor proteins like TRADD and TRAF2 (primarily regulate pro-survival pathways) are reduced. FADD, which primarily regulate cell death, its level remains unchanged. RIPK1, which regulate pro-survival, apoptosis and necroptosis, its expression and proteolysis (inhibits necroptosis but activates apoptosis) are increased.

CONCLUSIONS

The findings from the present study provide evidence towards the involvement of DR3, DR5, DR6, TL1A, TRAIL, TRADD, TRAF2, FADD and RIPK1 for the first time in prion diseases. The knowledge obtained from this research discuss the possible impacts of these 16 differentially expressed DR factors on our understanding towards the multifaceted neuropathology of prion diseases and towards future explorations into potential targeted therapeutic interventions for prion disease specific neuropathology.

Screening for Femoral Head Osteonecrosis Following COVID-19: Is It Worth It?

Objectives

Based on WHO data, as of June 2022, there were 532.2 million confirmed COVID-19 cases globally. In the initial phase of the COVID -19 pandemic, patients experiencing critical illness marked by severe respiratory distress were commonly subjected to corticosteroid treatment. Regrettably, the administration of exogenous corticosteroids stands as the prevailing cause of ONFH. In the current narrative review, we aim to evaluate if active screening should be utilized to diagnose post-COVID-19 ONFH in its early stages.

Methods

The databases for PubMed, CINAHL, and Science Direct were systematically queried in March 2022. The search terms were as follows: "COVID-19", "severe acute respiratory syndrome", "coronavirus", "systemic steroid", "corticosteroid", "femoral head osteonecrosis", "avascular necrosis", or "steroid therapy." The included studies for review were all required to be peer-reviewed studies in the English language with Reported complications linked to steroid therapy in COVID-19 patients or potential connections to the development of ONFH in individuals recovering from the novel coronavirus have been documented.

Results

Systemic corticosteroids were frequently employed in managing critically ill COVID-19 patients. The CDC reports up to June 2022 showed more than 4.8 million COVID-19 hospitalizations in the US, with approximately over one million patients receiving steroids. In a study of ONFH after infection with COVID-19, all patients had bilateral involvement. The average duration from the initiation of corticosteroid treatment to the onset of symptoms was 132.8 days.

Conclusion

In summary, a distinct correlation exists between the administration of steroids to individuals with COVID-19 and the subsequent risk of ONFH. Moreover, an elevated dosage and prolonged duration of steroid therapy in COVID-19 patients are associated with an increased likelihood of developing ONFH. Therefore, active screening for high-risk patients, that may have received systemic corticosteroid treatment during a COVID-19 illness, may be reasonable.

Role of inflammatory microenvironment: potential implications for improved breast cancer nano-targeted therapy

Tumor cells, inflammatory cells and chemical factors work together to mediate complex signaling networks, which forms inflammatory tumor microenvironment (TME). The development of breast cancer is closely related to the functional activities of TME. This review introduces the origins of cancer-related chronic inflammation and the main constituents of inflammatory microenvironment. Inflammatory microenvironment plays an important role in breast cancer growth, metastasis, drug resistance and angiogenesis through multifactorial mechanisms. It is suggested that inflammatory microenvironment contributes to providing possible mechanisms of drug action and modes of drug transport for anti-cancer treatment. Nano-drug delivery system (NDDS) becomes a popular topic for optimizing the design of tumor targeting drugs. It is seen that with the development of therapeutic approaches, NDDS can be used to achieve drug-targeted delivery well across the biological barriers and into cells, resulting in superior bioavailability, drug dose reduction as well as off-target side effect elimination. This paper focuses on the review of modulation mechanisms of inflammatory microenvironment and combination with nano-targeted therapeutic strategies, providing a comprehensive basis for further research on breast cancer prevention and control.

A data-driven computational model enables integrative and mechanistic characterization of dynamic macrophage polarization

Macrophages are highly plastic immune cells that dynamically integrate microenvironmental signals to shape their own functional phenotypes, a process known as polarization. Here we develop a large-scale mechanistic computational model that for the first time enables a systems-level characterization, from quantitative, temporal, dose-dependent, and single-cell perspectives, of macrophage polarization driven by a complex multi-pathway signaling network. The model was extensively calibrated and validated against literature and focused on in-house experimental data. Using the model, we generated dynamic phenotype maps in response to numerous combinations of polarizing signals; we also probed into an in silico population of model-based macrophages to examine the impact of polarization continuum at the single-cell level. Additionally, we analyzed the model under an in vitro condition of peripheral arterial disease to evaluate strategies that can potentially induce therapeutic macrophage repolarization. Our model is a key step toward the future development of a network-centric, comprehensive "virtual macrophage" simulation platform.

Discovery and validation an eight-biomarker serum gene signature for the diagnosis of steroid-induced osteonecrosis of the femoral head

Steroid-induced osteonecrosis of the femoral head (SONFH) is difficult to be diagnosed at the early stages when it can be administrated effectively. Yet, to date no study has been performed to identify diagnostic biomarkers and to develop diagnostic models for SONFH. In the current study, a total of 60 SONFH patients with Association Research Circulation Osseous (ARCO) stages I-IV, and 20 controls were enrolled and divided into the discovery and validation cohorts. The serum samples were collected and the gene expression profiles were detected by microarray analysis based on the discovery cohort. Then, eight genes (BIRC3, CBL, CCR5, LYN, PAK1, PTEN, RAF1 and TLR4) were identified as the candidate serum biomarkers of SONFH due to the significant differential expression patterns and the topological importance in the interaction network of SONFH-related differentially expressed genes. Functionally, these candidate serum biomarkers were significantly involved into several pathological processes during SONFH progression, such as the immune regulation and inflammation, bone metabolism and angiogenesis. After that, a prediction model for the diagnosis of SONFH was constructed using Partial least squares regression based on the serum levels of the candidate biomarkers. Notably, both the 10-fold cross-validation and the independent dataset test demonstrated the good performance of this model. In conclusion, our study discovered eight promising serum biomarkers and developed the multi-biomarker-based prediction model as a new, potential and non-invasive diagnostic tool for the detection of SONFH, as well as benefit the administration of SONFH in a daily clinical setting.

Complete Acid Ceramidase ablation prevents cancer-initiating cell formation in melanoma cells

Acid ceramidase (AC) is a lysosomal cysteine hydrolase that catalyzes the conversion of ceramide into fatty acid and sphingosine. This reaction lowers intracellular ceramide levels and concomitantly generates sphingosine used for sphingosine-1-phosphate (S1P) production. Since increases in ceramide and consequent decreases of S1P reduce proliferation of various cancers, AC might offer a new target for anti-tumor therapy. Here we used CrispR-Cas9-mediated gene editing to delete the gene encoding for AC, ASAH1, in human A375 melanoma cells. ASAH1-null clones show significantly greater accumulation of long-chain saturated ceramides that are substrate for AC. As seen with administration of exogenous ceramide, AC ablation blocks cell cycle progression and accelerates senescence. Importantly, ASAH1-null cells also lose the ability to form cancer-initiating cells and to undergo self-renewal, which is suggestive of a key role for AC in maintaining malignancy and self-renewal of invasive melanoma cells. The results suggest that AC inhibitors might find therapeutic use as adjuvant therapy for advanced melanoma.