Molecular cloning and expression of the Fas ligand, a novel member of the tumor necrosis factor family

Chemoproteomics Identifies State-Dependent and Proteoform-Selective Caspase-2 Inhibitors

Caspases are a highly conserved family of cysteine-aspartyl proteases known for their essential roles in regulating apoptosis, inflammation, cell differentiation, and proliferation. Complementary to genetic approaches, small-molecule probes have emerged as useful tools for modulating caspase activity. However, due to the high sequence and structure homology of all 12 human caspases, achieving selectivity remains a central challenge for caspase-directed small-molecule inhibitor development efforts. Here, using mass spectrometry-based chemoproteomics, we first identify a highly reactive noncatalytic cysteine that is unique to caspase-2. By combining both gel-based activity-based protein profiling (ABPP) and a tobacco etch virus (TEV) protease activation assay, we then identify covalent lead compounds that react preferentially with this cysteine and afford a complete blockade of caspase-2 activity. Inhibitory activity is restricted to the zymogen or precursor form of monomeric caspase-2. Focused analogue synthesis combined with chemoproteomic target engagement analysis in cellular lysates and in cells yielded both pan-caspase-reactive molecules and caspase-2 selective lead compounds together with a structurally matched inactive control. Application of this focused set of tool compounds to stratify the functions of the zymogen and partially processed (p32) forms of caspase-2 provide evidence to support that caspase-2-mediated response to DNA damage is largely driven by the partially processed p32 form of the enzyme. More broadly, our study highlights future opportunities for the development of proteoform-selective caspase inhibitors that target nonconserved and noncatalytic cysteine residues.

Synthesis of N-Glycosylated Soluble Fas Ligand

Controlled cell death is essential for the regulation of the immune system and plays a role in pathogen defense. It is often altered in pathogenic conditions such as cancer, viral infections and autoimmune diseases. The Fas receptor and its corresponding membrane-bound ligand (FasL) are part of the extrinsic apoptosis pathway activated in these cases. A soluble form of FasL (sFasL), produced by ectodomain shedding, displays a diverse but still elusive set of non-apoptotic functions and sometimes even serves as a pro-survival factor. To gather more knowledge about the characteristics of this protein and the impact N-glycosylations may have, access to homogeneous posttranslationally modified variants of sFasL is needed. Therefore, we developed a flexible strategy to obtain such homogeneously N-glycosylated variants of sFasL by applying chemical protein synthesis. This strategy can be flexibly combined with enzymatic methods to introduce more complex, site selective glycosylations.

TNF-Related Apoptosis-Inducing Ligand: Non-Apoptotic Signalling

TNF-related apoptosis-inducing ligand (TRAIL or Apo2 or TNFSF10) belongs to the TNF superfamily. When bound to its agonistic receptors, TRAIL can induce apoptosis in tumour cells, while sparing healthy cells. Over the last three decades, this tumour selectivity has prompted many studies aiming at evaluating the anti-tumoral potential of TRAIL or its derivatives. Although most of these attempts have failed, so far, novel formulations are still being evaluated. However, emerging evidence indicates that TRAIL can also trigger a non-canonical signal transduction pathway that is likely to be detrimental for its use in oncology. Likewise, an increasing number of studies suggest that in some circumstances TRAIL can induce, via Death receptor 5 (DR5), tumour cell motility, potentially leading to and contributing to tumour metastasis. While the pro-apoptotic signal transduction machinery of TRAIL is well known from a mechanistic point of view, that of the non-canonical pathway is less understood. In this study, we the current state of knowledge of TRAIL non-canonical signalling.

Redox mechanisms of environmental toxicants on male reproductive function

Humans and wildlife, including domesticated animals, are exposed to a myriad of environmental contaminants that are derived from various human activities, including agricultural, household, cosmetic, pharmaceutical, and industrial products. Excessive exposure to pesticides, heavy metals, and phthalates consequently causes the overproduction of reactive oxygen species. The equilibrium between reactive oxygen species and the antioxidant system is preserved to maintain cellular redox homeostasis. Mitochondria play a key role in cellular function and cell survival. Mitochondria are vulnerable to damage that can be provoked by environmental exposures. Once the mitochondrial metabolism is damaged, it interferes with energy metabolism and eventually causes the overproduction of free radicals. Furthermore, it also perceives inflammation signals to generate an inflammatory response, which is involved in pathophysiological mechanisms. A depleted antioxidant system provokes oxidative stress that triggers inflammation and regulates epigenetic function and apoptotic events. Apart from that, these chemicals influence steroidogenesis, deteriorate sperm quality, and damage male reproductive organs. It is strongly believed that redox signaling molecules are the key regulators that mediate reproductive toxicity. This review article aims to spotlight the redox toxicology of environmental chemicals on male reproduction function and its fertility prognosis. Furthermore, we shed light on the influence of redox signaling and metabolism in modulating the response of environmental toxins to reproductive function. Additionally, we emphasize the supporting evidence from diverse cellular and animal studies.

Notochordal cells: A potential therapeutic option for intervertebral disc degeneration

Intervertebral disc degeneration (IDD) is a prevalent musculoskeletal degenerative disorder worldwide, and ~40% of chronic low back pain cases are associated with IDD. Although the pathogenesis of IDD remains unclear, the reduction in nucleus pulposus cells (NPCs) and degradation of the extracellular matrix (ECM) are critical factors contributing to IDD. Notochordal cells (NCs), derived from the notochord, which rapidly degrades after birth and is eventually replaced by NPCs, play a crucial role in maintaining ECM homeostasis and preventing NPCs apoptosis. Current treatments for IDD only provide symptomatic relief, while lacking the ability to inhibit or reverse its progression. However, NCs and their secretions possess anti-inflammatory properties and promote NPCs proliferation, leading to ECM formation. Therefore, in recent years, NCs therapy targeting the underlying cause of IDD has emerged as a novel treatment strategy. This article provides a comprehensive review of the latest research progress on NCs for IDD, covering their biological characteristics, specific markers, possible mechanisms involved in IDD and therapeutic effects. It also highlights significant future directions in this field to facilitate further exploration of the pathogenesis of IDD and the development of new therapies based on NCs strategies.

Cell death

Cell death supports morphogenesis during development and homeostasis after birth by removing damaged or obsolete cells. It also curtails the spread of pathogens by eliminating infected cells. Cell death can be induced by the genetically programmed suicide mechanisms of apoptosis, necroptosis, and pyroptosis, or it can be a consequence of dysregulated metabolism, as in ferroptosis. Here, we review the signaling mechanisms underlying each cell-death pathway, discuss how impaired or excessive activation of the distinct cell-death processes can promote disease, and highlight existing and potential therapies for redressing imbalances in cell death in cancer and other diseases.

Immunoregulatory functions and therapeutic potential of natural killer cell-derived extracellular vesicles in chronic diseases

Extracellular vesicles (EVs) have been proven to play a significant immunoregulatory role in many chronic diseases, such as cancer and immune disorders. Among them, EVs derived from NK cells are an essential component of the immune cell functions. These EVs have been demonstrated to carry a variety of toxic proteins and nucleic acids derived from NK cells and play a therapeutic role in diseases like malignancies, liver fibrosis, and lung injury. However, natural NK-derived EVs (NKEVs) have certain limitations in disease treatment, such as low yield and poor targeting. Concurrently, NK cells exhibit characteristics of memory-like NK cells, which have stronger proliferative capacity, increased IFN-γ production, and enhanced cytotoxicity, making them more advantageous for disease treatment. Recent research has shifted its focus towards engineered extracellular vesicles and their potential to improve the efficiency, specificity, and safety of disease treatments. In this review, we will discuss the characteristics of NK-derived EVs and the latest advancements in disease therapy. Specifically, we will compare different cellular sources of NKEVs and explore the current status and prospects of memory-like NK cell-derived EVs and engineered NKEVs.

Novel PI(3)K-p85α/p110δ-ITK-LAT-PLC-γ2 and Fyn-ADAP-Carma1-TAK1 Pathways Define Reverse Signaling via FasL

The role of FasL in initiating death signals through Fas is well characterized. However, the reverse signaling pathway downstream of FasL in effector lymphocytes is poorly understood. Here, we identify that FasL functions as an independent activation receptor in NK cells. Activation via FasL results in the production of LFN-γ, GM-CSF, RANTES, MIP-1α, and MIP1-β. Proximal signaling of FasL requires Lck and Fyn. Upon activation, FasL facilitates the phosphorylation of PI(3)K-p85α/p55α subunits. A catalytically inactive PI(3)K-p110δD910A mutation significantly impairs the cytokine and chemokine production by FasL. Activation of ITK and LAT downstream of FasL plays a central role in recruiting and phosphorylating PLC-γ2. Importantly, Fyn-mediated recruitment of ADAP links FasL to the Carmal/ Bcl10/Tak1 signalosome. Lack of Carma1, CARD domain of Carma1, or Tak1 significantly reduces FasL-mediated cytokine and chemokine production. These findings, for the first time, provide a detailed molecular blueprint that defines FasL-mediated reverse signaling.

Faslpr gene dosage tunes the extent of lymphoproliferation and T cell differentiation in lupus

Sle1 and Faslpr are two lupus susceptibility loci that lead to manifestations of systemic lupus erythematosus. To evaluate the dosage effects of Faslpr in determining cellular and serological phenotypes associated with lupus, we developed a new C57BL/6 (B6) congenic lupus strain, B6.Sle1/Sle1.Faslpr/+ (Sle1homo.lprhet) and compared it with B6.Faslpr/lpr (lprhomo), B6.Sle1/Sle1 (Sle1homo), and B6.Sle1/Sle1.Faslpr/lpr (Sle1homo.lprhomo) strains. Whereas Sle1homo.lprhomo mice exhibited profound lymphoproliferation and early mortality, Sle1homo.lprhet mice had a lifespan comparable to B6 mice, with no evidence of splenomegaly or lymphadenopathy. Compared to B6 monogenic lupus strains, Sle1homo.lprhet mice exhibited significantly elevated serum ANA antibodies and increased proteinuria. Additionally, Sle1homo.lprhet T cells had an increased propensity to differentiate into Th1 cells. Gene dose effects of Faslpr were noted in upregulating serum IL-1⍺, IL-2, and IL-27. Taken together, Sle1homo.lprhet strain is a new C57BL/6-based model of lupus, ideal for genetic studies, autoantibody repertoire investigation, and for exploring Th1 effector cell skewing without early-age lymphoproliferative autoimmunity.

CD138 promotes the accumulation and activation of autoreactive T cells in autoimmune MRL/lpr mice

Autoreactive T cells, specifically CD138+ (syndecan-1) T cells produced in Fas-deficient systemic lupus erythematosus (SLE) mouse models, were shown to significantly promote the generation of autoantibodies. In the present study, Murphy Roths Large lymphoproliferative (MRL/lpr) lupus mice were used to investigate the role of CD138 protein expression in T cells in the progression of SLE. Measurement of flow cytometry, immunofluorescence and Luminex were performed to determine the effect of CD138 on T cells in MRL/lpr mice. The results demonstrate that CD138+ T cells induce apoptosis via a Fas-dependent pathway. CD138 protein expression in T cells of MRL/lpr mice significantly reduced T cell apoptosis and contributed to the accumulation of T cells and double negative (DN) T cells, whilst simultaneously promoting T cell activation in Fas-deficient lupus mice. CD138 protein expression in DN T cells also significantly increased the protein expression of Fas ligand to enhance the cytotoxicity of DN T cells. Furthermore, phorbol 12-myristate 13-acetate and ionomycin (PI) stimulation reduced CD138 protein expression in CD3+ T cells and prevented CD138+ T cell accumulation by inducing specific apoptosis. PI stimulation also activated T cells in MRL/lpr mice to increase CD69 protein expression. CD69 protein expression in CD138+ T cells significantly increased the frequency of apoptotic CD138+ T cells. In addition, results from the present study demonstrated that CD138- T cells of MRL/lpr lupus mice had an activation defect. CD138 protein expression in T cells significantly reversed the defective activation and activating T cells could significantly reduce CD138 protein expression in CD3+ T cells of MRL/lpr mice. This suggests that CD138 protein expression in CD3+CD138- T cells of MRL/lpr mice may be a consequence of the impaired activation in autoreactive T cells prior to exposure to self-antigens by the immune system. CD138 expression in autoreactive T cells has a central role in promoting the progression and development of autoimmune response in MRL/lpr mice.

CD95 (Fas) and CD95L (FasL)-mediated non-canonical signaling pathways

Although the interaction of CD95L (also known as FasL) with its so-called death receptor CD95 (Fas) induces an apoptotic signal responsible for the elimination of infected and cancer cells and maintenance of tissue homeostasis, this receptor can also implement non apoptotic signaling pathways. This latter signaling is involved in metastatic dissemination in certain cancers and the severity of auto-immune disorders. The signaling complexity of this pair is increased by the fact that CD95 expression itself seems to contribute to oncogenesis via a CD95L-independent manner and, that both ligand and receptor might interact with other partners modulating their pathophysiological functions. Finally, CD95L itself can trigger cell signaling in immune cells rendering complex the interpretation of mouse models in which CD95 or CD95L are knocked out. Herein, we discuss these non-canonical responses and their biological functions.

Chemoproteomics identifies proteoform-selective caspase-2 inhibitors

Caspases are a highly conserved family of cysteine-aspartyl proteases known for their essential roles in regulating apoptosis, inflammation, cell differentiation, and proliferation. Complementary to genetic approaches, small-molecule probes have emerged as useful tools for modulating caspase activity. However, due to the high sequence and structure homology of all twelve human caspases, achieving selectivity remains a central challenge for caspase-directed small-molecule inhibitor development efforts. Here, using mass spectrometry-based chemoproteomics, we first identify a highly reactive non-catalytic cysteine that is unique to caspase-2. By combining both gel-based activity-based protein profiling (ABPP) and a tobacco etch virus (TEV) protease activation assay, we then identify covalent lead compounds that react preferentially with this cysteine and afford a complete blockade of caspase-2 activity. Inhibitory activity is restricted to the zymogen or precursor form of monomeric caspase-2. Focused analogue synthesis combined with chemoproteomic target engagement analysis in cellular lysates and in cells yielded both pan-caspase reactive molecules and caspase-2 selective lead compounds together with a structurally matched inactive control. Application of this focused set of tool compounds to stratify caspase contributions to initiation of intrinsic apoptosis, supports compensatory caspase-9 activity in the context of caspase-2 inactivation. More broadly, our study highlights future opportunities for the development of proteoform-selective caspase inhibitors that target non-conserved and non-catalytic cysteine residues.

Formulated chitosan-sodium tripolyphosphate nanoparticles for co-encapsulation of ellagic acid and anti-inflammatory peptide: characterization, stability and anti-inflammatory activity

BACKGROUND

Chitosan (CS) and tripolyphosphate (TPP) can be combined in the development of a material with synergistic properties and promising potential for the conservation of food products. In this study, ellagic acid (EA) and anti-inflammatory peptide (FPL)-loaded CS nanoparticles (FPL/EA NPs) were prepared using the ionic gelation method and optimal preparation conditions were obtained through a single factor design.

RESULTS

The synthesized nanoparticles (NPs) were characterized using a scanning electron microscope (SEM), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and differential scanning calorimetry (DSC). Nanoparticles were spherical, with an average size of 308.33 ± 4.61 nm, a polydispersity index (PDI) of 0.254, a zeta potential of +31.7 ± 0.08 mV, and a high encapsulation capacity (22.16 ± 0.79%). An in vitro release study showed that EA/FPL had a sustainable release from FPL/EA NPs. The stability of the FPL/EA NPs was evaluated for 90 days at 0, 25, and 37 °C. Significant anti-inflammatory activity of FPL/EA NPs was verified by nitric oxide (NO) and tumor necrosis factor-α (TNF-α) reduction.

CONCLUSION

These characteristics support the use of CS nanoparticles to encapsulate EA and FPL and improve their bioactivity in food products. © 2023 Society of Chemical Industry.

Elevated Foxo3a and Fas-ligand expression in human periapical granulomas as a potential treatment target

OBJECTIVE

Periapical granuloma is a common periodontitis type involving chronic inflammation; however, the efficacy of current therapies is limited. Its molecular pathogenesis also remains obscure. Forkhead box transcription factor class o3a (Foxo3a) and Fas-ligand (FasL) are associated with chronic inflammation. Therefore, in this study, we aimed to clarify the roles of Foxo3a and FasL in periapical granuloma pathophysiology.

SUBJECTS AND METHODS

Periapical lesions were obtained from patients during endodontic surgery and tooth extraction; those diagnosed with periapical granulomas using haematoxylin and eosin staining were further analysed. Immunohistochemical analysis was performed for Foxo3a and FasL, and real-time polymerase chain reaction was performed for FOXO3A, FASL and interleukin (IL)-1β. Healthy gingival tissues were also examined as controls.

RESULTS

Neutrophils, lymphocytes and plasma cells in the periapical granulomas, but not healthy tissues, expressed Foxo3a. Dual-colour immunofluorescence imaging revealed Foxo3a and FasL co-expression in leukocytes. FOXO3A, FASL and IL-1β mRNA levels in healthy gingival tissues were significantly lower than those in the periapical granulomas. Additionally, FOXO3A and IL-1β expressions were negatively correlated.

CONCLUSIONS

Phosphorylated Foxo3a may reduce IL-1β release by inhibiting apoptosis through FasL in periapical periodontitis and prevent exacerbation. Thus, Foxo3a is a potential therapeutic agent for periapical periodontitis.

Ocular immune privilege and retinal pigment epithelial cells

The ocular tissue microenvironment is immune-privileged and uses multiple immunosuppressive mechanisms to prevent the induction of inflammation. The retinal pigment epithelium plays an essential role in ocular immune privilege. In addition to serving as a blood barrier separating the fenestrated choriocapillaris from the retina, the retinal pigment epithelium is a source of immunosuppressive cytokines and membrane-bound negative regulators that modulate the activity of immune cells within the retina. This article reviews the current understanding of how retinal pigment epithelium cells mediate immune regulation, focusing on the changes under pathologic conditions.

FasL is a catabolic factor in alveolar bone homeostasis

AIM

Fas ligand (FasL) belongs to the tumour necrosis factor superfamily regulating bone turnover, inflammation, and apoptosis. The appendicular and axial skeleton phenotype of mature Faslgld mice has been reported. The impact of FasL on the alveolar bone providing support for the teeth at mature stages under healthy and induced inflammatory conditions remains unknown.

MATERIALS AND METHODS

We performed a phenotypical analysis of mice carrying the homozygous Faslgld mutation and wild-type (WT) mice (C57BL/6) under healthy conditions and upon ligature-induced periodontitis. After 12 days, micro-computed tomography analysis revealed the distance between the cement enamel junction and the alveolar bone crest. Additional structural parameters, such as the bone volume fraction (BV/TV) and the periodontal ligament space volume, were measured. Histological analyses were performed to visualize the catabolic changes at the defect site.

RESULTS

Healthy Faslgld mice were found to have more periodontal bone than their WT littermates. Faslgld had no significant effect on inflammatory osteolysis compared to WT controls with ligatures. Histology revealed eroded surfaces at the root and in the inter-proximal bone in both strains.

CONCLUSIONS

Our findings suggest that FasL is a catabolic factor in alveolar bone homeostasis but it does not affect the inflammatory osteolysis.

CD95/Fas ligand induced toxicity

The role of CD95/Fas ligand (CD95L/FasL) in the induction of CD95-mediated extrinsic apoptosis is well characterized. Trimerized, membrane-bound CD95L ligates the CD95 receptor activating downstream signaling resulting in the execution of cells by caspase proteins. However, the expression of CD95L has been reported to induce cell death in contexts in which this pathway is unlikely to be activated, such as in cell autonomous activation induced cell death (AICD) and in CD95-resistant cancer cell lines. Recent data suggests that the CD95L mRNA exerts toxicity through death induced by survival gene elimination (DISE). DISE results from the targeting of networks of survival genes by toxic short RNA (sRNA)s in the RNA-induced silencing complex (RISC). CD95L mRNA contributes to this death directly, through the processing of its mRNA into toxic sRNAs that are loaded into the RISC, and indirectly, by promoting the loading of other toxic sRNAs. Interestingly, CD95L is not the only mRNA that is processed and loaded into the RISC. Protein-coding mRNAs involved in protein translation are also selectively loaded. We propose a model in which networks of mRNA-derived sRNAs modulate DISE, with networks of genes providing non-toxic RISC substrate sRNAs that protect against DISE, and opposing networks of stress-activated genes that produce toxic RISC substrate sRNAs that promote DISE.

Autophagy of naïve CD4+ T cells in aging - the role of body adiposity and physical fitness

Life expectancy has increased exponentially in the last century accompanied by disability, poor quality of life, and all-cause mortality in older age due to the high prevalence of obesity and physical inactivity in older people. Biologically, the aging process reduces the cell's metabolic and functional efficiency, and disrupts the cell's anabolic and catabolic homeostasis, predisposing older people to many dysfunctional conditions such as cardiovascular disease, neurodegenerative disorders, cancer, and diabetes. In the immune system, aging also alters cells' metabolic and functional efficiency, a process known as 'immunosenescence', where cells become more broadly inflammatory and their functionality is altered. Notably, autophagy, the conserved and important cellular process that maintains the cell's efficiency and functional homeostasis may protect the immune system from age-associated dysfunctional changes by regulating cell death in activated CD4+ T cells. This regulatory process increases the delivery of the dysfunctional cytoplasmic material to lysosomal degradation while increasing cytokine production, proliferation, and differentiation of CD4+ T cell-mediated immune responses. Poor proliferation and diminished responsiveness to cytokines appear to be ubiquitous features of aged T cells and may explain the delayed peak in T cell expansion and cytotoxic activity commonly observed in the 'immunosenescence' phenotype in the elderly. On the other hand, physical exercise stimulates the expression of crucial nutrient sensors and inhibits the mechanistic target of the rapamycin (mTOR) signaling cascade which increases autophagic activity in cells. Therefore, in this perspective review, we will first contextualize the overall view of the autophagy process and then, we will discuss how body adiposity and physical fitness may counteract autophagy in naïve CD4+ T cells in aging.

Revisiting autoimmune lymphoproliferative syndrome caused by Fas ligand mutations

BACKGROUND

Fas ligand (FasL) is expressed by activated T cells and induces death in target cells upon binding to Fas. Loss-of-function FAS or FASLG mutations cause autoimmune-lymphoproliferative syndrome (ALPS) characterized by expanded double-negative T cells (DNT) and elevated serum biomarkers. While most ALPS patients carry heterozygous FAS mutations, FASLG mutations are rare and usually biallelic. Only 2 heterozygous variants were reported, associated with an atypical clinical phenotype.

OBJECTIVE

We revisited the significance of heterozygous FASLG mutations as a cause of ALPS.

METHODS

Clinical features and biomarkers were analyzed in 24 individuals with homozygous or heterozygous FASLG variants predicted to be deleterious. Cytotoxicity assays were performed with patient T cells and biochemical assays with recombinant FasL.

RESULTS

Homozygous FASLG variants abrogated cytotoxicity and resulted in early-onset severe ALPS with elevated DNT, raised vitamin B₁₂, and usually no soluble FasL. In contrast, heterozygous variants affected FasL function by reducing expression, impairing trimerization, or preventing Fas binding. However, they were not associated with elevated DNT and vitamin B₁₂, and they did not affect FasL-mediated cytotoxicity. The dominant-negative effects of previously published variants could not be confirmed. Even Y166C, causing loss of Fas binding with a dominant-negative effect in biochemical assays, did not impair cellular cytotoxicity or cause vitamin B₁₂ and DNT elevation.

CONCLUSION

Heterozygous loss-of-function mutations are better tolerated for FASLG than for FAS, which may explain the low frequency of ALPS-FASLG.

Plasma Levels of sFas-sFasL and FASL Gene Expression Are Associated with Tuberculosis

Apoptosis of macrophages infected by Mycobacterium tuberculosis via Fas-FasL is an important immune mechanism against infection. This study investigated the association of tuberculosis (TB) with the presence of the polymorphisms FAS -670A/G and FASL -124A/G, the levels of sFas and sFasL, and the gene expression of FASL and cytokines. Samples of 200 individuals diagnosed with TB and 200 healthy controls were evaluated. Real-time PCR (genotyping and gene expression) and ELISA (dosages of sFas, sFasL, IFN-γ, and IL-10) tests were performed. There was no association of FAS -670A/G and FASL -124A/G polymorphisms with TB. The TB group exhibited high plasma levels of sFas and reduced plasma levels of sFasL (p < 0.05). The correlation analysis between these markers revealed a positive correlation between the levels of sFas and sFasL, sFasL and FASL expression, and between sFas and FASL expression (p < 0.05). In the TB group, there was a positive correlation between FASL expression and IFN-γ levels and higher levels of IL-10 compared to IFN-γ (p < 0.05). High levels of sFas and reduced levels of sFasL and FASL expression may contribute to the inhibition of apoptosis in infected cells and represent a possible bacterial resistance resource to maintain the infection.

Progestin Resistance and Corresponding Management of Abnormal Endometrial Hyperplasia and Endometrial Carcinoma

With a younger tendency in morbidity age, endometrial cancer (EC) incidence has grown year after year. Worse, even more commonly occurring is endometrial hyperplasia (EH), which is a precancerous endometrial proliferation. For young women with early EC and EH who want to preserve fertility, progestin therapy has been utilized as a routine fertility-preserving treatment approach. Nevertheless, progestin medication failure in some patients is mostly due to progestin resistance and side effects. In order to further analyze the potential mechanisms of progestin resistance in EH and EC, to provide theoretical support for effective therapeutic strategies, and to lay the groundwork for searching novel treatment approaches, this article reviews the current therapeutic effects of progestin in EH and EC, as well as the mechanisms and molecular biomarkers of progestin resistance, and systematically expounds on the potential therapeutic methods to overcome progestin resistance.

Role of metalloproteases in the CD95 signaling pathways

CD95L (also known as FasL or CD178) is a member of the tumor necrosis family (TNF) superfamily. Although this transmembrane ligand has been mainly considered as a potent apoptotic inducer in CD95 (Fas)-expressing cells, more recent studies pointed out its role in the implementation of non-apoptotic signals. Accordingly, this ligand has been associated with the aggravation of inflammation in different auto-immune disorders and in the metastatic occurrence in different cancers. Although it remains to decipher all key factors involved in the ambivalent role of this ligand, accumulating clues suggest that while the membrane bound CD95L triggers apoptosis, its soluble counterpart generated by metalloprotease-driven cleavage is responsible for its non-apoptotic functions. Nonetheless, the metalloproteases (MMPs and ADAMs) involved in the CD95L shedding, the cleavage sites and the different stoichiometries and functions of the soluble CD95L remain to be elucidated. To better understand how soluble CD95L triggers signaling pathways from apoptosis to inflammation or cell migration, we propose herein to summarize the different metalloproteases that have been described to be able to shed CD95L, their cleavage sites and the biological functions associated with the released ligands. Based on these new findings, the development of CD95/CD95L-targeting therapeutics is also discussed.

Immune Checkpoint and Other Receptor-Ligand Pairs Modulating Macrophages in Cancer: Present and Prospects

Immunotherapy, especially immune checkpoint blocking, has become the primary anti-tumor treatment in recent years. However, the current immune checkpoint inhibitor (ICI) therapy is far from satisfactory. Macrophages are a key component of anti-tumor immunity as they are a common immune cell subset in tumor tissues and act as a link between innate and adaptive immunity. Hence, understanding the regulation of macrophage activation in tumor tissues by receptor-ligand interaction will provide promising macrophage-targeting strategies to complement current adaptive immunity-based immunotherapy and traditional anti-tumor treatment. This review aims to offer a systematic summary of the current advances in number, structure, expression, biological function, and interplay of immune checkpoint and other receptor-ligand between macrophages and tumor cells.

Genetic polymorphisms and their effects on the severity of silicosis in workers exposed to silica in Brazil

Objective: Silicosis is a pneumoconiosis characterized by fibrosis of the lung parenchyma caused by inhalation of silica particles. Genetic factors might play a role in the severity silicosis. We sought to evaluate the influence of polymorphisms in the ACE, FAS, FASLG, NOS2, IL1RN, FAM13A, TGFB1, and TNF genes on the severity of silicosis. Methods: Nine polymorphisms were genotyped by PCR in a sample of 143 patients with silicosis in the state of Rio de Janeiro, Brazil. Results: Fifty-seven patients (40%) were classified as having simple silicosis and 86 (60%) were classified as having complicated silicosis. The TT genotype of rs1800469 in the TGFB1 gene showed a protective effect for complicated silicosis (OR = 0.35; 95% CI, 0.14-0.92; p = 0.028) when compared with the other two genotypes (CC+CT). The polymorphic T allele of rs763110 in the FASLG gene (OR = 0.56; 95% CI, 0.31-0.99; p = 0.047), as well as a dominant model for the T allele (TT+CT: OR = 0.37; 95% CI, 0.15-0.96; p = 0.037), also showed a protective effect. When patients with simple silicosis despite having been exposed to silica for a longer time (> 44,229 hours) were compared with patients with complicated silicosis despite having been exposed to silica for a shorter time, the T allele of rs763110 in the FASLG gene (OR = 0.20; 95% CI, 0.08-0.48; p < 0.0001), as well as dominant and recessive models (OR = 0.06; 95% CI, 0.00-0.49; p = 0.01 and OR = 0.22; 95% CI, 0.06-0.77; p = 0.014, respectively), showed a protective effect against the severity of silicosis. Conclusions: It appears that rs1800469 polymorphisms in the TGFB1 gene and rs763110 polymorphisms in the FASLG gene are involved in the severity of silicosis. Given the lack of studies relating genetic polymorphisms to the severity of silicosis, these results should be replicated in other populations.

Non-cytotoxic functions of CD8 T cells: “repentance of a serial killer”

Cytotoxic CD8 T cells (CTLs) are classically described as the “serial killers” of the immune system, where they play a pivotal role in protective immunity against a wide spectrum of pathogens and tumors. Ironically, they are critical drivers of transplant rejection and autoimmune diseases, a scenario very similar to the famous novel “The strange case of Dr. Jekyll and Mr. Hyde”. Until recently, it has not been well-appreciated whether CTLs can also acquire non-cytotoxic functions in health and disease. Several investigations into this question revealed their non-cytotoxic functions through interactions with various immune and non-immune cells. In this review, we will establish a new classification for CD8 T cell functions including cytotoxic and non-cytotoxic. Further, we will discuss this novel concept and speculate on how these functions could contribute to homeostasis of the immune system as well as immunological responses in transplantation, cancer, and autoimmune diseases.

Low quantity and quality of anti-spike humoral response is linked to CD4 T-cell apoptosis in COVID-19 patients

In addition to an inflammatory reaction, Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2)-infected patients present lymphopenia, which we recently reported as being related to abnormal programmed cell death. As an efficient humoral response requires CD4 T-cell help, we hypothesized that the propensity of CD4 T cells to die may impact the quantity and quality of the humoral response in acutely infected individuals. In addition to specific immunoglobulins (Ig)A, IgM, and IgG against SARS-CoV-2 nucleocapsid (N), membrane (M), and spike (S1) proteins, we assessed the quality of IgG response by measuring the avidity index. Because the S protein represents the main target for neutralization and antibody-dependent cellular cytotoxicity responses, we also analyzed anti-S-specific IgG using S-transfected cells (S-Flow). Our results demonstrated that most COVID-19 patients have a predominant IgA anti-N humoral response during the early phase of infection. This specific humoral response preceded the anti-S1 in time and magnitude. The avidity index of anti-S1 IgG was low in acutely infected individuals compared to convalescent patients. We showed that the percentage of apoptotic CD4 T cells is inversely correlated with the levels of specific IgG antibodies. These lower levels were also correlated positively with plasma levels of CXCL10, a marker of disease severity, and soluble Fas ligand that contributes to T-cell death. Finally, we found lower S-Flow responses in patients with higher CD4 T-cell apoptosis. Altogether, these results demonstrate that individuals with high levels of CD4 T-cell apoptosis and CXCL10 have a poor ability to build an efficient anti-S response. Consequently, preventing CD4 T-cell death might be a strategy for improving humoral response during the acute phase, thereby reducing COVID-19 pathogenicity.

Self-Assembling Imageable Silk Hydrogels for the Focal Treatment of Osteosarcoma

Background: The standard treatment for osteosarcoma comprises complete surgical resection and neoadjuvant chemotherapy, which may cause serious side effects and partial or total limb loss. Therefore, to avoid the disadvantages of traditional treatment, we developed self-assembling imageable silk hydrogels for osteosarcoma.

Methods: We analysed whether iodine induced apoptosis in MG-63 and Saos-2 cells by using CCK-8 and flow cytometry assays and transmission electron microscopy. Western blotting was used to analyse the pathway of iodine-induced apoptosis in osteosarcoma cells. PEG400, silk fibroin solution, polyvinylpyrrolidone iodine (PVP-I), and meglumine diatrizoate (MD) were mixed to produce an imageable hydrogel. A nude mouse model of osteosarcoma was established, and the hydrogel was injected locally into the interior of the osteosarcoma with X-ray guidance. The therapeutic effect and biosafety of the hydrogel were evaluated.

Results: Iodine treatment at 18 and 20 µM for 12 h resulted in cell survival rate reduced to 50 ± 2.1% and 50.5 ± 2.7% for MG-63 and Sao-2 cells, respectively (p < 0.01). The proportion of apoptotic cells was significantly higher in the iodine-treatment group than in the control group (p < 0.05), and apoptotic bodies were observed by transmission electron microscopy. Iodine could regulate the death receptor pathway and induce MG-63 and Saos-2 cell apoptosis. The hydrogels were simple to assemble, and gels could be formed within 38 min. A force of less than 50 N was required to inject the gels with a syringe. The hydrogels were readily loaded and led to sustained iodine release over 1 week. The osteosarcoma volume in the PEG-iodine-silk/MD hydrogel group was significantly smaller than that in the other three groups (p < 0.001). Caspase-3 and poly (ADP-ribose) polymerase (PARP) expression levels were significantly higher in the PEG-iodine-silk/MD hydrogel group than in the other three groups (p < 0.001). Haematoxylin and eosin (H&E) staining showed no abnormalities in the heart, liver, spleen, lung, kidney, pancreas or thyroid in any group.

Conclusions: Self-assembling imageable silk hydrogels could be injected locally into osteosarcoma tissues with X-ray assistance. With the advantages of good biosafety, low systemic toxicity and minimal invasiveness, self-assembling imageable silk hydrogels provide a promising approach for improving the locoregional control of osteosarcoma.

Apigenin Increases Natural Killer Cytotoxicity to Human Hepatocellular Carcinoma Expressing HIF-1α through High Interaction of CD95/CD95L

Natural killer (NK) cell activity is more attenuated in hepatocellular carcinoma (HCC) patients than normal. Hypoxic-inducible factor (HIF)-1α is highly expressed in tumors to maintain their metabolism in a hypoxic environment. The expression of HIF-1α in cancers can lead to cell growth, proliferation, invasion/metastasis and immune escape. Although apigenin, a flavonoid, is known to have various biological activities, it has not been demonstrated in NK cell immune activity in HCC cells. In this study, NK-92 cells were directly cocultured with HCC SK-Hep1 cells for 24 h to evaluate NK cell activity in HCC cells or HCC cells expressing HIF-1α by apigenin. NK cell cytotoxicity to HCC cells expressing HIF-1α was significantly increased, and NK cell-activating receptors, NKG2D, NKp30 and NKp44 were highly expressed. The activating effect of apigenin on NK cells substantially induced apoptosis in HCC cells expressing HIF-1α through high expression of CD95L on the surface of NK-92 cells. Moreover, apigenin excellently inhibited the level of TGF-β1 in a coculture of NK cells and HCC cells. In conclusion, apigenin seems to be a good compound that increases NK cell cytotoxicity to HCC cells by controlling HIF-1α expression.

Role of Apoptosis in HIV Pathogenesis

The apoptotic pathway is an important cell death pathway that contributes to the maintenance of homeostasis in living systems. However, variations in apoptosis have been linked to many diseases such as cancers and chronic infections. The HIV infection has contributed to increase mortality and morbidity worldwide, predominantly through the induction of gradual depletion of CD4+ T cells. The induction and mediation of both the intrinsic and extrinsic apoptotic pathways are crucial in HIV pathogenesis and intracellular survival. Consequently, a deep molecular understanding of how apoptosis is induced and modulated in HIV-mediated CD4+ T cell depletion is paramount, as this can lead to new portals of therapeutic intervention and control.

Emerging Issues Questioning the Current Treatment Strategies for Lumbar Disc Herniation

Lumbar disc herniation is among the common phenotypes of degenerative lumbar spine diseases, significantly affecting patients' quality of life. The practice pattern is diverse. Choosing conservative measures or surgical treatments is still controversial in some areas. For those who have failed conservative treatment, surgery with or without instrumentation is recommended, causing significant expenditures and frustrating complications, that should not be ignored. In the article, we performed a literature review and summarized the evidence by subheadings to unravel the cons of surgical intervention for lumbar disc herniation. There are tetrad critical issues about surgical treatment of lumbar disc herniation, i.e., favorable natural history, insufficient evidence in a recommendation of fusion surgery for patients, metallosis, and implant removal. Firstly, accumulating evidence reveals immune privilege and auto-immunity hallmarks of human lumbar discs within the closed niche. Progenitor cells within human discs further expand the capacity with the endogenous repair. Clinical watchful follow-up studies with repeated diagnostic imaging reveal spontaneous resolution for lumbar disc herniation, even calcified tissues. Secondly, emerging evidence indicates long-term complications of lumbar fusion, such as adjacent segment disease, pseudarthrosis, implant failure, and sagittal spinal imbalance, which get increasing attention. Thirdly, systemic and local reactions (metallosis) for metal instrumentation have been noted with long-term health concerns and toxicity. Fourthly, the indications and timing for spinal implant removal have not reached a consensus. Other challenging issues include postoperative lumbar stiffness. The review provided evidence from a negative perspective for surgeons and patients who attempt to choose surgical treatment. Collectively, the emerging underlying evidence questions the benefits of traditional surgery for patients with lumbar disc herniation. Therefore, the long-term effects of surgery should be closely observed. Surgical decisions should be made prudently for each patient.

Immune regulation of the ocular surface

Despite constant exposure to various environmental stimuli, the ocular surface remains intact and uninflamed while maintaining the transparency of the cornea and its visual function. This 'immune privilege' of the ocular surface is not simply a result of the physical barrier function of the mucosal lining but, more importantly, is actively maintained through a variety of immunoregulatory mechanisms that prevent the disruption of immune homeostasis. In this review, we focus on essential molecular and cellular players that promote immune quiescence in steady-state conditions and suppress inflammation in disease-states. Specifically, we examine the interactions between the ocular surface and its local draining lymphoid compartment, by encompassing the corneal epithelium, corneal nerves and cornea-resident myeloid cells, conjunctival goblet cells, and regulatory T cells (Treg) in the context of ocular surface autoimmune inflammation (dry eye disease) and alloimmunity (corneal transplantation). A better understanding of the immunoregulatory mechanisms will facilitate the development of novel, targeted immunomodulatory strategies for a broad range of ocular surface inflammatory disorders.

T cell apoptosis characterizes severe Covid-19 disease

Severe SARS-CoV-2 infections are characterized by lymphopenia, but the mechanisms involved are still elusive. Based on our knowledge of HIV pathophysiology, we hypothesized that SARS-CoV-2 infection-mediated lymphopenia could also be related to T cell apoptosis. By comparing intensive care unit (ICU) and non-ICU COVID-19 patients with age-matched healthy donors, we found a strong positive correlation between plasma levels of soluble FasL (sFasL) and T cell surface expression of Fas/CD95 with the propensity of T cells to die and CD4 T cell counts. Plasma levels of sFasL and T cell death are correlated with CXCL10 which is part of the signature of 4 biomarkers of disease severity (ROC, 0.98). We also found that members of the Bcl-2 family had modulated in the T cells of COVID-19 patients. More importantly, we demonstrated that the pan-caspase inhibitor, Q-VD, prevents T cell death by apoptosis and enhances Th1 transcripts. Altogether, our results are compatible with a model in which T-cell apoptosis accounts for T lymphopenia in individuals with severe COVID-19. Therefore, a strategy aimed at blocking caspase activation could be beneficial for preventing immunodeficiency in COVID-19 patients.

CD95/Fas suppresses NF-κB activation through recruitment of KPC2 in a CD95L/FasL-independent mechanism

CD95 expression is preserved in triple-negative breast cancers (TNBCs), and CD95 loss in these cells triggers the induction of a pro-inflammatory program, promoting the recruitment of cytotoxic NK cells impairing tumor growth. Herein, we identify a novel interaction partner of CD95, Kip1 ubiquitination-promoting complex protein 2 (KPC2), using an unbiased proteomic approach. Independently of CD95L, CD95/KPC2 interaction contributes to the partial degradation of p105 (NF-κB1) and the subsequent generation of p50 homodimers, which transcriptionally represses NF-κB-driven gene expression. Mechanistically, KPC2 interacts with the C-terminal region of CD95 and serves as an adaptor to recruit RelA (p65) and KPC1, which acts as E3 ubiquitin-protein ligase promoting the degradation of p105 into p50. Loss of CD95 in TNBC cells releases KPC2, limiting the formation of the NF-κB inhibitory homodimer complex (p50/p50), promoting NF-κB activation and the production of pro-inflammatory cytokines, which might contribute to remodeling the immune landscape in TNBC cells.

Single neonatal irradiation induces long-term gene expression changes in the thyroid gland, which may be involved in the tumorigenesis

Exposure to ionizing radiation in childhood has been recognized as a risk factor for thyroid cancer. We previously demonstrated that neonatal X-irradiation induced specific deformation of the thyroid follicles. Here, we further analyzed this model to understand the possible relationship with thyroid carcinogenesis. Wistar rats were subjected to cervical X-irradiation at different ages of 1–8 weeks old and at different doses of 1.5–12 Gy. For tumor promotion, rats were fed with an iodine-deficient diet (IDD). In cervically X-irradiated neonatal rats, the size of thyroid follicles decreased, accompanied by an increase in the number of TUNEL-positive cells. Fas and Lgals3 mRNA levels increased, while Mct8 and Lat4 expressions decreased. The co-administration of IDD induced the proliferation and the upregulation in Lgals3 expression, resulting in thyroid adenoma development at 28 weeks post-exposure. Our data demonstrated that single neonatal X-irradiation induced continuous apoptotic activity in the thyroid with the long-term alternation in Fas, Mct8, Lat4, and Lgals3 mRNA expressions. Some of these changes were similar to those induced by IDD, suggesting that neonatal X-irradiation may partially act as a thyroid tumor promoter. These radiation-induced thyroidal changes may be enhanced by the combined treatment with IDD, resulting in the early development of thyroid adenoma.

Fas and microRNAs Variations as a Possible Risk for Behçet Disease

BACKGROUND

Behçet disease (BD) belongs to a disease family that has a transparent borderline between autoinflammatory and autoimmune disorders. Fas and some miRNAs have revealed to display remarkable roles in both autoimmune and autoinflammatory processes, and they can play important roles in defective apoptosis in BD. We investigated the association of the susceptibility of BD with Fas, miRNA variations, and their both single and combined presence in a Turkish population as a case-control study.

METHODS

The distributions of FAS-670 A>G rs1800682, mir146a rs2910164, and mir196a rs11614913 polymorphisms are analyzed with the polymerase chain reaction-restriction fragment length polymorphism method in 115 BD patients and 220 controls in 6-month period.

RESULTS

Statistical analysis indicates that in the case of Fas-670 A/G rs1800682, AA genotype and A allele have a protective role in BD (p = 0.0004 and p = 0.0009, respectively). The dominant model (AA + AG/GG) also displays a protective effect on BD unlike the recessive model (p = 0.03). In addition, both homozygous genotype (CC) of rs2910164 of mir-146a (p = 0.04) and the dominant model (CC + CG vs. GG) have protective effects on BD unlike the recessive model (p < 0.0001). Both mir-196a2 rs1800682 polymorphism and combined genotype analysis of rs1800682-rs2910164 and rs1800682-rs11614913 gave no statistically significant differences within the groups for genotypes and either of the alleles (p > 0.05).

CONCLUSIONS

These findings indicate that both Fas rs1800682 and mir-146a rs2910164 variants might be important factors participating in the protection against BD in the Turkish population.

Over Fifty Years of Life, Death, and Cannibalism: A Historical Recollection of Apoptosis and Autophagy

Research in biomedical sciences has changed dramatically over the past fifty years. There is no doubt that the discovery of apoptosis and autophagy as two highly synchronized and regulated mechanisms in cellular homeostasis are among the most important discoveries in these decades. Along with the advancement in molecular biology, identifying the genetic players in apoptosis and autophagy has shed light on our understanding of their function in physiological and pathological conditions. In this review, we first describe the history of key discoveries in apoptosis with a molecular insight and continue with apoptosis pathways and their regulation. We touch upon the role of apoptosis in human health and its malfunction in several diseases. We discuss the path to the morphological and molecular discovery of autophagy. Moreover, we dive deep into the precise regulation of autophagy and recent findings from basic research to clinical applications of autophagy modulation in human health and illnesses and the available therapies for many diseases caused by impaired autophagy. We conclude with the exciting crosstalk between apoptosis and autophagy, from the early discoveries to recent findings.

Review of cancer cell resistance mechanisms to apoptosis and actual targeted therapies

The apoptosis pathway is a programmed cell death mechanism that is crucial for cellular and tissue homeostasis and organ development. There are three major caspase-dependent pathways of apoptosis that ultimately lead to DNA fragmentation. Cancerous cells are known to highly regulate the apoptotic pathway and its role in cancer hallmark acquisition has been discussed over the past decades. Numerous mutations in cancer cell types have been reported to be implicated in chemoresistance and treatment outcome. In this review, we summarize the mutations of the caspase-dependant apoptotic pathways that are the source of cancer development and the targeted therapies currently available or in trial.

Varicocele-Mediated Male Infertility: From the Perspective of Testicular Immunity and Inflammation

Background

Varicocele (VC) is present in 35 - 40% of men with infertility. However, current surgical and antioxidant treatments are not completely effective. In addition to oxidative stress, it is likely that other factors such as testicular immune microenvironment disorder contribute to irreversible testicular. Evidence suggests that VC is associated with anti-sperm antibodies (ASAs), spermatogenesis and testosterone secretion abnormalities, and testicular cytokine production. Moreover, inhibition of inflammation can alleviate VC-mediated pathogenesis. The normal function of the testis depends on its immune tolerance mechanism. Testicular immune regulation is complex, and many infectious or non-infectious diseases may damage this precision system.

Results

The testicular immune microenvironment is composed of common immune cells and other cells involved in testicular immunity. The former includes testicular macrophages, T cells, dendritic cells (DCs), and mast cells, whereas the latter include Leydig cells and Sertoli cells (SCs). In animal models and in patients with VC, most studies have revealed an abnormal increase in the levels of ASAs and pro-inflammatory cytokines such as interleukin (IL)-1 and tumor necrosis factor (TNF)-alpha in the seminal plasma, testicular tissue, and even peripheral blood. It is also involved in the activation of potential inflammatory pathways, such as the nucleotide-binding oligomerization domain-like receptor family pyrin domain containing (NLRP)-3 pathway. Finally, the development of VC-mediated infertility (VMI) may be facilitated by abnormal permeability of proteins, such as claudin-11, that constitute the blood-testis barrier (BTB).

Conclusions

The testicular immune response, including the production of ASAs and inflammatory factors, activation of inflammatory pathways, and destruction of the BTB may be involved in the pathogenesis of VMI it is necessary to further explore how patient outcomes can be improved through immunotherapy.

Autoimmunity in dry eye disease - An updated review of evidence on effector and memory Th17 cells in disease pathogenicity

The classic Th1/Th2 dogma has been significantly reshaped since the subsequent introduction of several new T helper cell subsets, among which the most intensively investigated during the last decade is the Th17 lineage that demonstrates critical pathogenic roles in autoimmunity and chronic inflammation - including the highly prevalent dry eye disease. In this review, we summarize current concepts of Th17-mediated disruption of ocular surface immune homeostasis that leads to autoimmune inflammatory dry eye disease, by discussing the induction, activation, differentiation, migration, and function of effector Th17 cells in disease development, highlighting the phenotypic and functional plasticity of Th17 lineage throughout the disease initiation, perpetuation and sustention. Furthermore, we emphasize the most recent advance in Th17 memory formation and function in the chronic course of dry eye disease, a major area to be better understood for facilitating the development of effective treatments in a broader field of autoimmune diseases that usually present a chronic course with recurrent episodes of flare in the target tissues or organs.

New Advances in the Research of Resistance to Neoadjuvant Chemotherapy in Breast Cancer

Breast cancer has an extremely high incidence in women, and its morbidity and mortality rank first among female tumors. With the increasing development of medicine today, the clinical application of neoadjuvant chemotherapy has brought new hope to the treatment of breast cancer. Although the efficacy of neoadjuvant chemotherapy has been confirmed, drug resistance is one of the main reasons for its treatment failure, contributing to the difficulty in the treatment of breast cancer. This article focuses on multiple mechanisms of action and expounds a series of recent research advances that mediate drug resistance in breast cancer cells. Drug metabolizing enzymes can mediate a catalytic reaction to inactivate chemotherapeutic drugs and develop drug resistance. The drug efflux system can reduce the drug concentration in breast cancer cells. The combination of glutathione detoxification system and platinum drugs can cause breast cancer cells to be insensitive to drugs. Changes in drug targets have led to poorer efficacy of HER2 receptor inhibitors. Moreover, autophagy, epithelial–mesenchymal transition, and tumor microenvironment can all contribute to the development of resistance in breast cancer cells. Based on the relevant research on the existing drug resistance mechanism, the current treatment plan for reversing the resistance of breast cancer to neoadjuvant chemotherapy is explored, and the potential drug targets are analyzed, aiming to provide a new idea and strategy to reverse the resistance of neoadjuvant chemotherapy drugs in breast cancer.

Ginsenoside Rb1 protects from Staphylococcus aureus-induced oxidative damage and apoptosis through endoplasmic reticulum-stress and death receptor-mediated pathways

Acute lung injury (ALI) is acute uncontrolled inflammation of lung tissue that leads to high fatality both in human and animals. Staphylococcus aureus (S. aureus) could be an opportunistic, versatile bacterial etiology of ALI. Ginsenoside Rb1 (Rb1) is extracted from the Panax ginseng, which displays a wide range of biological and pharmacological effects. However, protective effects of Rb1 in S. aureus-induced ALI though endoplasmic reticulum (ER) stress and death receptor-mediated pathways have not yet been reported. Therefore, present study was planned with the aims to investigate the antioxidant and anti-apoptotic properties of Rb1 through regulation of ER stress as well as death receptor-mediated pathways in ALI induced by S. aureus in mice. In this study, four groups of healthy Kunming mice (n = 48) were used. The S. aureus (80 µl; 1 ×10⁷ CFU/10 µl) was administered intranasally to establish mice model of ALI. After 24 h of onset of S. aureus-induced ALI, the mice were injected thrice with Rb1 (40 mg/kg) intraperitoneally six hours apart. Histopathology, enzyme linked immunosorbent assay (ELISA), real time quantitative polymerase chain reaction (RT-qPCR), Immunohistochemistry and western blotting assay were employed in the current study. Our results suggested that Rb1 administration save lungs from pulmonary injury by reducing wet to dry (W/D) ratio, protein levels, total cells, neutrophilic count, reactive oxygen species (ROS), myeloperoxidase (MPO), malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (Gpx)1 depletion. Meanwhile, Rb1 therapy ameliorated histopathology alteration of lung tissue and pro-inflammatory cytokines secretion. The gene expression of ER stress marker (PERK, AFT-6, IRE1 and CHOP) were upregulated markedly (P < .05) in S. aureus-instilled groups, which was reduced by Rb1 administration that is reveled from the result findings of the RT-qPCR and immunoblot assay. The results of immunohistochemistry for CHOP indicated the increased expression in S. aureus groups which in turn ameliorated by Rb1 treatment. The mRNA expression demonstrated that death receptor-associated genes (FasL, Fas, FADD and caspase-8) showed up-regulation in S. aureus group. The similar findings were observed for the protein expression of caspase-8, FADD and Fas. Rb1 treatment markedly (P < .05) reversed protein and mRNA expression levels of these death receptor-associated genes when compared to the S. aureus group. Taken together, Rb1 attenuated S. aureus-induced oxidative damage via the ER stress-mediated pathway and apoptosis through death receptor-mediated pathway. Conclusively, our findings provide an insight into preventive mechanism of Rb1 in ALI caused by S. aureus and hence proven a scientific baseline for the therapeutic application of Rb1.

Molecular Perspective of Nanoparticle Mediated Therapeutic Targeting in Breast Cancer: An Odyssey of Endoplasmic Reticulum Unfolded Protein Response (UPRER) and Beyond

Breast cancer (BC) is the second most frequent cause of death among women. Representing a complex and heterogeneous type of cancer, its occurrence is attributed by both genetic (gene mutations, e.g., BRCA1, BRCA2) and non-genetic (race, ethnicity, etc.) risk factors. The effectiveness of available treatment regimens (small molecules, cytotoxic agents, and inhibitors) decreased due to their poor penetration across biological barriers, limited targeting, and rapid body clearance along with their effect on normal resident cells of bone marrow, gastrointestinal tract, and hair follicles. This significantly reduced their clinical outcomes, which led to an unprecedented increase in the number of cases worldwide. Nanomedicine, a nano-formulation of therapeutics, emerged as a versatile delivering module for employment in achieving the effective and target specific delivery of pharmaceutical payloads. Adoption of nanotechnological approaches in delivering therapeutic molecules to target cells ensures not only reduced immune response and toxicity, but increases the stability of therapeutic entities in the systemic circulation that averts their degradation and as such increased extravasations and accumulation via enhanced permeation and the retention (EPR) effect in target tissues. Additionally, nanoparticle (NP)-induced ER stress, which enhances apoptosis and autophagy, has been utilized as a combative strategy in the treatment of cancerous cells. As nanoparticles-based avenues have been capitalized to achieve better efficacy of the new genera of therapeutics with enhanced specificity and safety, the present study is aimed at providing the fundamentals of BC, nanotechnological modules (organic, inorganic, and hybrid) employed in delivering different therapeutic molecules, and mechanistic insights of nano-ER stress induced apoptosis and autophagy with a perspective of exploring this avenue for use in the nano-toxicological studies. Furthermore, the current scenario of USA FDA approved nano-formulations and the future perspective of nanotechnological based interventions to overcome the existing challenges are also discussed.

FasL Is Required for Osseous Healing in Extraction Sockets in Mice

Fas ligand (FasL) is a member of the tumor necrosis factor (TNF) superfamily involved in the activation of apoptosis. Assuming that apoptosis is initiated after tooth extraction it is reasonable to suggest that FasL may play a pivotal role in the healing of extraction sockets. Herein, we tested the hypothesis of whether the lack of FasL impairs the healing of extraction sockets. To this end, we extracted upper right incisors of FasL knockout (KO) mice and their wildtype (WT) littermates. After a healing period of two weeks, bone volume over total volume (BV/TV) via µCT and descriptive histological analyses were performed. µCT revealed that BV/TV in the coronal region of the socket amounted to 39.4% in WT and 21.8% in KO, with a significant difference between the groups (p=0.002). Likewise, in the middle region of the socket, BV/TV amounted to 50.3% in WT and 40.8% in KO (p<0.001). In the apical part, however, no difference was noticed. Consistently, WT mice displayed a significantly higher median trabecular thickness and a lower trabecular separation when compared to the KO group at the coronal and central region of the socket. There was the overall tendency that in both, female and male mice, FasL affects bone regeneration. Taken together, these findings suggest that FasL deficiency may reduce bone regeneration during the healing process of extraction sockets.

Natural Killer Cell-Derived Extracellular Vesicles: Novel Players in Cancer Immunotherapy

Natural killer (NK) cells are critical components of host innate immunity and function as the first line of defense against tumors and viral infection. There is increasing evidence that extracellular vesicles (EVs) are involved in the antitumor activity of NK cells. NK cell-derived EVs (NKEVs) carrying cargo such as cytotoxic proteins, microRNAs, and cytokines employ multiple mechanisms to kill tumor cells, but also exhibit immunomodulatory activity by stimulating other immune cells. Several studies have reported that NKEVs can reverse immune suppression under tolerogenic conditions and contribute to NK-mediated immune surveillance against tumors. Thus, NKEVs are a promising tool for cancer immunotherapy. In this review, we describe the biological effects and potential applications of NKEVs in antitumor immunity.

Current Pharmacogenetic Perspective on Stevens-Johnson Syndrome and Toxic Epidermal Necrolysis

Adverse drug reactions are a public health issue that draws widespread attention, especially for Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) which have high mortality and lack of efficacious treatment. Though T-cell-mediated HLA-interacted immune response has been extensively studied, our understanding of the mechanism is far from satisfactory. This review summarizes infection (virus, bacterial, and mycoplasma infection), an environmental risk factor, as a trigger for SJS/TEN. The mutations or polymorphisms of drug metabolic enzymes, transporters, receptors, the immune system genes, and T-cell-mediated apoptosis signaling pathways that contribute to SJS/TEN are discussed and summarized. Epigenetics, metabolites, and mobilization of regulatory T cells and tolerogenic myeloid precursors are emerged directions to study SJS/TEN. Ex vivo lymphocyte transformation test has been exploited to aid in identifying the causative drugs. Critical questions on the pathogenesis of SJS/TEN underlying gene polymorphisms and T cell cytotoxicity remain: why some of the patients carrying the risky genes tolerate the drug and do not develop SJS/TEN? What makes the skin and mucous membrane so special to be targeted? Do they relate to skin/mucous expression of transporters? What is the common machinery underlying different HLA-B alleles associated with SJS/TEN and common metabolites?

Circulating sFasL Levels Predict the Severity and Outcome of Burn Injury: A Prospective Observational Study

BACKGROUND

Severe burn injury activates shock, inflammation, and blood cell system, but inappropriate reactions may lead to adverse outcomes. Soluble Fas ligand (sFasL) participates in apoptosis and inflammatory response. The circulating sFasL levels we investigated in association with the burn severity, shock, inflammation, blood cells, and mortality in patients with severe burns.

METHODS

A total of 56 patients with severe burns were recruited. The levels of sFasL and the biomarkers reflecting shock, organ damage, inflammation, and blood cells at 48 h postburn were analyzed. We compared the practical situation of patients that stratified by median sFasL levels and investigated the predictive value of sFasL for mortality.

RESULTS

High circulating sFasL levels were associated with the higher degrees of burn index, shock index, lactate, N-terminal probrain natriuretic peptide, total bilirubin, blood urea nitrogen, creatinine, tumor necrosis factor-α, interleukin-1β, interleukin-8, intercellular adhesion molecule 1, and complement 3, and the lower degrees of oxygenation index, lymphocytes, and platelets. Multiple linear regression analysis showed that the higher tumor necrosis factor-α (P < 0.001) and the lower oxygenation index (P = 0.031) and lymphocytes (P = 0.043) were associated with the higher sFasL. High sFasL (a unit is 50 ng/L) (odds ratio [OR] 5.50 [95% CI 1.04-29.20], P = 0.045) was an independent predictor of increased mortality by multivariate logistic regression analysis.

CONCLUSIONS

High circulating sFasL at 48 h postburn in patients with severe burns reflect shock, proinflammatory response, organ damage, and lymphocyte reductions and predict 30-day mortality.

Embryo Buoyancy and Cell Death Gene Expression During Embryogenesis of Yellow-Tail Kingfish Seriola lalandi

In pelagic fish, embryo buoyancy is a noteworthy aspect of the reproductive strategy, and is associated with overall quality, survival, and further developmental success. In captivity, the loss of buoyancy of early embryos correlates with high mortality that might be related to massive cell death. Therefore, the aim of this study was to evaluate under captivity conditions the expression of genes related to the apoptosis process during the early embryonic development of the pelagic fish Seriola lalandi, and its relationship to the buoyancy of embryos. The relative expression of bcl2, bax-like, casp9, casp8, and casp3 was evaluated by RT-qPCR and FasL/Fas protein levels by western blot in five development stages of embryos sorted as floating or low-floating. All genes examined were expressed in both floating and low-floating embryos up to 24 h of development. Expression of the pro-apoptotic factors bax, casp9, casp8, and casp3 was higher in low-floating as compared with floating embryos in a developmental stage-specific manner. In contrast, there was no difference in expression of bcl2 between floating and low-floating embryos. Fas protein was detected as a single band in floating embryos without changes in expression throughout development; however, in low-floating embryos, three higher intensity reactive bands were detected in the 24-h embryos. Interestingly, FasL was only detected at 24-h in floating embryos, whereas in low-floating samples this ligand was present at all stages, with a sharp increase as development progressed. Cell death, as evaluated by the terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling assay, was highly increased in low-floating embryos as compared to floating embryos throughout all developmental stages, with the highest levels observed during the gastrula stage and at 24 h. The results of this study suggest that an increase in cell death, probably associated with the intrinsic and extrinsic apoptosis pathways, is present in low-floating embryos that might explain their lower developmental potential under captivity conditions.

Transforming growth factor-β1-regulated Fas/FasL pathway activation suppresses nucleus pulposus cell apoptosis in an inflammatory environment

Background: During disc degeneration, inflammatory cytokine tumor necrosis factor (TNF)-α is correlated with nucleus pulposus (NP) cell apoptosis. Transforming growth factor (TGF)-β1 has the potential to regenerate degenerative disc.

Objective: To investigate the protective role of TGF-β1 against TNF-α-mediated NP cell apoptosis and the underlying mechanism.

Methods: Rat NP cells were treated with TNF-α (100 ng/ml) for 48 h. TGF-β1 was added into the culture medium to investigate its protective effects against TNF-α-induced NP cell apoptosis. Exogenous FasL was used to investigate the potential role of the Fas/FasL pathway in this process. Flow cytometry assay was used to analyze NP cell apoptosis. Real-time PCR and Western blotting were used to analyze gene and protein expression of apoptosis-related molecules.

Results: In TNF-α-treated NP cells, TGF-β1 significantly decreased NP cell apoptosis, declined caspase-3 and -8 activity, and decreased expression of Bax and caspase-3 (cleaved-caspase-3) but increased expression of Bcl-2. However, exogenous FasL partly reversed these effects of TGF-β1 in NP cells treated with TNF-α. Additionally, expression of Fas and FasL in TNF-α-treated NP cells partly decreased by TGF-β1, whereas exogenous FasL increased expression of Fas and FasL in NP cells treated with TGF-β1 and TNF-α.

Conclusion: TGF-β1 helps to inhibit TNF-α-induced NP cell apoptosis and the Fas/FasL pathway may be involved in this process. The present study suggests that TGF-β1 may be effective to retard inflammation-mediated disc degeneration.

Double-negative T cells in autoimmune diseases

PURPOSE OF REVIEW

TCRαβ+CD4-CD8- double-negative T (DNT) cells, a principal subset of mature T lymphocytes, have been closely linked with autoimmune/inflammatory conditions. However, controversy persists regarding their ontogeny and function. Here, we present an overview on DNT cells in different autoimmune diseases to advance a deeper understanding of the contribution of this population to disease pathogenesis.

RECENT FINDINGS

DNT cells have been characterized in various chronic inflammatory diseases and they have been proposed to display pathogenic or regulatory function. The tissue location of DNT cells and the effector cytokines they produce bespeak to their active involvement in chronic inflammatory diseases.

SUMMARY

By producing various cytokines, expanded DNT cells in inflamed tissues contribute to the pathogenesis of a variety of autoimmune inflammatory diseases. However, it is unclear whether this population represents a stable lineage consisting of different subsets similar to CD4+ T helper cell subset. Better understanding of the possible heterogeneity and plasticity of DNT cells is needed to reveal interventional therapeutic opportunities.