IL-6, monocyte infiltration and parenchymal cells

NLRP3 Inflammasome Involvement in Heart, Liver, and Lung Diseases-A Lesson from Cytokine Storm Syndrome

Inflammation and inflammasomes have been proposed as important regulators of the host-microorganism interaction, playing a key role in morbidity and mortality due to the coronavirus disease 2019 (COVID-19) in subjects with chronic conditions and compromised immune system. The inflammasome consists of a multiprotein complex that finely regulates the activation of caspase-1 and the production and secretion of potent pro-inflammatory cytokines such as IL-1β and IL-18. The pyrin containing NOD (nucleotide-binding oligomerization domain) like receptor (NLRP) is a family of intracellular receptors, sensing patterns associated to pathogens or danger signals and NLRP3 inflammasome is the most deeply analyzed for its involvement in the innate and adaptive immune system as well as its contribution to several autoinflammatory and autoimmune diseases. It is highly expressed in leukocytes and up-regulated in sentinel cells upon inflammatory stimuli. NLRP3 expression has also been reported in B and T lymphocytes, in epithelial cells of oral and genital mucosa, in specific parenchymal cells as cardiomyocytes, and keratinocytes, and chondrocytes. It is well known that a dysregulated activation of the inflammasome is involved in the pathogenesis of different disorders that share the common red line of inflammation in their pathogenetic fingerprint. Here, we review the potential roles of the NLRP3 inflammasome in cardiovascular events, liver damage, pulmonary diseases, and in that wide range of systemic inflammatory syndromes named as a cytokine storm.

Cytokines and Hepatocellular Carcinoma: Biomarkers of a Deadly Embrace

Hepatocellular carcinoma (HCC) represents a worldwide health matter with a major care burden, high prevalence, and poor prognosis. Its pathogenesis mainly varies depending on the underlying etiological factors, although it develops from liver cirrhosis in the majority of cases. This review summarizes the role of the most interesting soluble factors as biomarkers for early diagnosis and as recommended targets for treatment in accordance with the new challenges in precision medicine. In the premalignant environment, inflammatory cells release a wide range of cytokines, chemokines, growth factors, prostaglandins, and proangiogenic factors, making the liver environment more suitable for hepatocyte tumor progression that starts from acquired genetic mutations. A complex interaction of pro-inflammatory (IL-6, TNF-α) and anti-inflammatory cytokines (TGF-α and -β), pro-angiogenic molecules (including the Angiopoietins, HGF, PECAM-1, HIF-1α, VEGF), different transcription factors (NF-kB, STAT-3), and their signaling pathways are involved in the development of HCC. Since cytokines are expressed and released during the different stages of HCC progression, their measurement, by different available methods, can provide in-depth information on the identification and management of HCC.

Mono/polyclonal free light chains as challenging biomarkers for immunological abnormalities

Free light chain (FLC) kappa (k) and lambda (λ) consist of low molecular weight proteins produced in excess during immunoglobulin synthesis and secreted into the circulation. In patients with normal renal function, over 99% of FLCs are filtered and reabsorbed. Thus, the presence of FLCs in the serum is directly related to plasma cell activity and the balance between production and renal clearance. FLCs are bioactive molecules that may exist as monoclonal (m) and polyclonal (p) FLCs. These have been detected in several body fluids and may be key indicators of ongoing damage and/or illness. International guidelines now recommend mFLC for screening, diagnosis and monitoring multiple myeloma and other plasma cell dyscrasias. In current clinical practice, FLCs in urine indicate cast nephropathy and other renal injury, whereas their presence in cerebrospinal fluid is important for identifying central nervous system inflammatory diseases such as multiple sclerosis. Increased pFLCs have also been detected in various conditions characterized by B cell activation, i.e., chronic inflammation, autoimmune disease and HCV infection. Monitoring the coronavirus (COVID-19) pandemic by analysis of salivary FLCs presents a significant opportunity in clinical immunology worthy of scientific pursuit.

The Extracellular Vesicles from the Commensal Staphylococcus Epidermidis ATCC12228 Strain Regulate Skin Inflammation in the Imiquimod-Induced Psoriasis Murine Model

Extracellular vesicles (EVs) are evaginations of the cytoplasmic membrane, containing nucleic acids, proteins, lipids, enzymes, and toxins. EVs participate in various bacterial physiological processes. Staphylococcus epidermidis interacts and communicates with the host skin. S. epidermidis’ EVs may have an essential role in this communication mechanism, modulating the immunological environment. This work aimed to evaluate if S. epidermidis’ EVs can modulate cytokine production by keratinocytes in vitro and in vivo using the imiquimod-induced psoriasis murine model. S. epidermidis’ EVs were obtained from a commensal strain (ATC12228EVs) and a clinical isolated strain (983EVs). EVs from both origins induced IL-6 expression in HaCaT keratinocyte cultures; nevertheless, 983EVs promoted a higher expression of the pro-inflammatory cytokines VEGF-A, LL37, IL-8, and IL-17F than ATCC12228EVs. Moreover, in vivo imiquimod-induced psoriatic skin treated with ATCC12228EVs reduced the characteristic psoriatic skin features, such as acanthosis and cellular infiltrate, as well as VEGF-A, IL-6, KC, IL-23, IL-17F, IL-36γ, and IL-36R expression in a more efficient manner than 983EVs; however, in contrast, Foxp3 expression did not significantly change, and IL-36 receptor antagonist (IL-36Ra) was found to be increased. Our findings showed a distinctive immunological profile induction that is dependent on the clinical or commensal EV origin in a mice model of skin-like psoriasis. Characteristically, proteomics analysis showed differences in the EVs protein content, dependent on origin of the isolated EVs. Specifically, in ATCC12228EVs, we found the proteins glutamate dehydrogenase, ornithine carbamoyltransferase, arginine deiminase, carbamate kinase, catalase, superoxide dismutase, phenol-soluble β1/β2 modulin, and polyglycerol phosphate α-glucosyltransferase, which could be involved in the reduction of lesions in the murine imiquimod-induced psoriasis skin. Our results show that the commensal ATCC12228EVs have a greater protective/attenuating effect on the murine imiquimod-induced psoriasis by inducing IL-36Ra expression in comparison with EVs from a clinical isolate of S. epidermidis.

Solving the mystery of HBV-related mixed cryoglobulinemia: potential biomarkers of disease progression

OBJECTIVES

The biomarkers of an immunological dysregulation due to a chronic HBV infection are indeed understudied. If untreated, this condition may evolve into liver impairment co-occurring with extrahepatic involvements. Here, we aim to identify a new panel of biomarkers [including immunoglobulin G (IgG) subclasses, RF, and Free Light Chains (FLCs)] that may be useful and reliable for clinical evaluation of HBV-related cryoglobulinemia.

METHODS

We retrospectively analysed clinical data from 44 HBV-positive patients. The patients were stratified (according to the presence/absence of mixed cryoglobulinemia) into two groups: 22 with cryoglobulins (CGs) and 22 without CGs. Samples from 20 healthy blood donors (HDs) were used as negative controls. Serum samples were tested for IgG subclasses, RF (-IgM, -IgG, and -IgA type), and FLCs.

RESULTS

We detected a strikingly different distribution of serum IgG subclasses between HDs and HBV-positive patients, together with different RF isotypes; in addition, FLCs were significantly increased in HBV-positive patients compared with HDs, while no significant difference was shown between HBV-positive patients with/without mixed cryoglobulinemia.

CONCLUSION

The immune-inflammatory response triggered by HBV may be monitored by a peculiar profile of biomarkers. Our results open a new perspective in the precision medicine era; in these challenging times, they could also be employed to monitor the clinical course of those COVID-19 patients who are at high risk of HBV reactivation due to liver impairment and/or immunosuppressive therapies.

Serum and urine free light chains measurements in patients with systemic sclerosis: novel biomarkers for disease activity

Circulating free light chains (FLCs), considered biomarkers of B cell activity, are frequently elevated in patients affected by systemic inflammatory autoimmune diseases. As the systemic sclerosis (SSc) clinical course can be variable, this study is aimed at evaluating FLCs levels in affected individuals as biomarkers of disease activity. We assessed FLC levels in serum and urine of 72 SSc patients and 30 healthy controls (HC). Results were analyzed in comparison with overall clinical and laboratory findings, disease activity index (DAI) and disease severity scale (DSS). SSc patients displayed increased levels of κ and λ FLC in serum significantly higher than HC (p = 0.0001) alongside the mean values of free κ/λ ratio and κ + λ sum (p = 0.0001). SSc patients showed increased free κ in urine with a κ/λ higher than HC (p = 0.0001). SSc patients with increased κ + λ in serum showed that erythro-sedimentation rate (p = 0.034), C-reactive protein (p = 0.003), DAI (p = 0.024) and DSS (p = 0.015) were higher if compared to SSc patients with normal levels of FLC. A positive linear correlation was found between serum levels of free κ and DAI (r = 0.29, p = 0.014). In addition, SSc patients with increased free κ in urine had higher DAI (p = 0.048) than SSc patients with normal κ levels. Our results strengthen the role of serum FLC as useful biomarker in clinical practice to early diagnosis and monitor disease activity, showing for the first time that also urine FLC levels correlated with disease activity in SSc patients.

COVID-19 and hepatic involvement: The liver as a main actor of the pandemic novel

In the natural history of SARS-CoV-2 infection, liver injury is frequent but quite mild and it is defined as any liver damage occurring during disease progression and treatment of infection in patients with or without pre-existing liver diseases. The underlying mechanisms for hepatic injury in patients with COVID-19 are still unclear but the liver damage in SARS-CoV-2 infection seems to be directly caused by virus-induced cytopathic effects. In this review, we will summarize all data of updated literature, regarding the relationship between SARS-CoV-2 infection, acute response and liver involvement. An overview will be given on liver injury, liver transplant and the possible consequences of COVID-19 in patients with pre-existing liver diseases.

Diagnosis, Screening and Treatment of Patients with Palmoplantar Pustulosis (PPP): A Review of Current Practices and Recommendations

Palmoplantar pustulosis (PPP) is a rare, chronic, recurrent inflammatory disease that affects the palms and/or the soles with sterile, erupting pustules, which are debilitating and usually resistant to treatment. It has genetic, histopathologic and clinical features that are not present in psoriasis; thus, it can be classified as a variant of psoriasis or as a separate entity. Smoking and upper respiratory infections have been suggested as main triggers of PPP. PPP is a challenging disease to manage, and the treatment approach involves both topical and systemic therapies, as well as phototherapy and targeted molecules. No gold standard therapy has yet been identified, and none of the treatments are curative. In patients with mild disease, control may be achieved with on-demand occlusion of topical agents. In patients with moderate-to-severe PPP, phototherapy or a classical systemic agent (acitretin being the best treatment option, especially in combination with PUVA) may be effective. Refractory patients or those with contraindications to use these therapies may be good candidates for apremilast or biologic therapy, particularly anti-IL-17A and anti-IL-23 agents. Recent PPP trials are focusing on blockage of IL-36 or IL-1 pathways, which play an important role in innate immunity. Indeed, IL-36 isoforms have been strongly implicated in the pathogenesis of psoriasis. Therefore, blockage of the IL-36 pathway has become a new treatment target in PPP, and three studies are currently evaluating the use of monoclonal antibodies that block the IL-36 receptor in PPP: ANB019 and spesolimab (BI 655130). In this review, we explore the diagnosis, screening and treatment of patients with PPP.

Inactivation of MTOR promotes autophagy-mediated epithelial injury in particulate matter-induced airway inflammation

Particulate matter (PM) is able to induce airway epithelial injury, while the detailed mechanisms remain unclear. Here we demonstrated that PM exposure inactivated MTOR (mechanistic target of rapamycin kinase), enhanced macroautophagy/autophagy, and impaired lysosomal activity in HBE (human bronchial epithelial) cells and in mouse airway epithelium. Genetic or pharmaceutical inhibition of MTOR significantly enhanced, while inhibition of autophagy attenuated, PM-induced IL6 expression in HBE cells. Consistently, club-cell-specific deletion of Mtor aggravated, whereas loss of Atg5 in bronchial epithelium reduced, PM-induced airway inflammation. Interestingly, the augmented inflammatory responses caused by MTOR deficiency were markedly attenuated by blockage of downstream autophagy both in vitro and in vivo. Mechanistically, the dysregulation of MTOR-autophagy signaling was partially dependent on activation of upstream TSC2, and interacted with the TLR4-MYD88 to orchestrate the downstream NFKB activity and to regulate the production of inflammatory cytokines in airway epithelium. Moreover, inhibition of autophagy reduced the expression of EPS15 and the subsequent endocytosis of PM. Taken together, the present study provides a mechanistic explanation for how airway epithelium localized MTOR-autophagy axis regulates PM-induced airway injury, suggesting that activation of MTOR and/or suppression of autophagy in local airway might be effective therapeutic strategies for PM-related airway disorders.Abbreviations: ACTB: actin beta; AKT: AKT serine/threonine kinase; ALI: air liquid interface; AP2: adaptor related protein complex 2; ATG: autophagy related; BALF: bronchoalveolar lavage fluid; COPD: chronic obstructive pulmonary disease; CXCL: C-X-C motif chemokine ligand; DOX: doxycycline; EGF: epidermal growth factor; EGFR: epidermal growth factor receptor; EPS15: epidermal growth factor receptor pathway substrate 15; HBE: human bronchial epithelial; H&E: hematoxylin & eosin; IKK: IKB kinase; IL: interleukin; LAMP2: lysosomal-associated membrane protein 2; LPS: lipopolysaccharide; MAP1LC3B/LC3B: microtubule-associated protein 1 light chain 3 beta; MTEC: mouse tracheal epithelial cells; MTOR: mechanistic target of rapamycin kinase; MYD88: MYD88 innate immune signal transduction adaptor; NFKB: nuclear factor of kappa B; NFKBIA: NFKB inhibitor alpha; PM: particulate matter; PtdIns3K: phosphatidylinositol 3-kinase; Rapa: rapamycin; RELA: RELA proto-oncogene, NFKB subunit; SCGB1A1: secretoglobin family 1A member 1; siRNA: small interfering RNAs; SQSTM1: sequestosome 1; TEM: transmission electronic microscopy; TLR4: toll like receptor 4; TSC2: TSC complex subunit 2.

Role of interleukin-6 in regulation of immune responses to remodeling after myocardial infarction

Myocardial remodeling following myocardial infarction (MI) is emerging as key causes of chronic infarct mortality. Interleukin-6 is a classic pro-inflammatory cytokine needed to mount an effective immune response. It seems that interleukin-6 acts as an important role in the dynamic and superbly orchestrated process of innate immunity after MI. Interleukin-6 timely suppresses of innate immune signals to prevent the catastrophic consequences of uncontrolled inflammation on cardiac geometry and function, and thus tunes myocardial remodeling. A comprehensive understanding of biological processes of interleukin-6 in innate immunity leading to inflammatory response and disease-related ventricular remodeling is helpful to find the solution of chronic heart failure. To accomplish this, we reviewed the articles of interleukin-6 regard to inflammation, innate immunity, and cardiac remodeling. This review focuses on the role of interleukin-6 that dominates cell-mediated immunity, especially on neutrophils, monocytes, macrophages, and fibroblasts. In addition, we will also briefly discuss other inflammatory cytokines involved in this process within the paper.

A Study of Inflammatory/Necrosis Biomarkers in the Fracture of the Femur Treated with Proximal Femoral Nail Antirotation

Pertrochanteric fractures are common injuries in adults and source of morbidity and mortality among the elderly. Different surgical techniques were recommended for their treatment but undoubtedly they add an additional inflammatory trauma along the fracture itself. Many attempts to quantify the degree of approach-related trauma are carried out through measurements of systemic inflammatory parameters. In this study we prospectively analyzed laboratory data of 20 patients over eighty with pertrochanteric fracture of the femur treated with proximal femoral nail antirotation (PFNA). This is an excellent device for osteosynthesis because it can be easily and quickly inserted by a mini-incision providing stable fixation and early full mobilization. Serum tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), C-reactive protein (CRP), and plasma creatin kinase (CK) were evaluated 1 hour preoperatively and 24 hours postoperatively. Our results show that PFNA did not induce significant increments in serum levels of inflammatory cytokines TNF-α and IL-6; CRP was elevated preoperatively in correlation with waiting time for surgery; CRP and CK showed a significant increment in the first postoperatory day; CK increment was correlated with surgical time length. We conclude that, for the markers we analyzed, PFNA shows a low biomechanical-inflammatory profile that represents an advantage over other techniques.

IL-6 as a druggable target in psoriasis: focus on pustular variants

Psoriasis vulgaris (PV) is a cutaneous inflammatory disorder stemming from abnormal, persistent activation of the interleukin- (IL-)23/Th17 axis. Pustular psoriasis (PP) is a clinicopathological variant of psoriasis, histopathologically defined by the predominance of intraepidermal collections of neutrophils. Although PP pathogenesis is thought to largely follow that of (PV), recent evidences point to a more central role for IL-1, IL-36, and IL-6 in the development of PP. We review the role of IL-6 in the pathogenesis of PV and PP, focusing on its cross-talk with cytokines of the IL-23/Th17 axis. Clinical inhibitors of IL-6 signaling, including tocilizumab, have shown significant effectiveness in the treatment of several inflammatory rheumatic diseases, including rheumatoid arthritis and juvenile idiopathic arthritis; accordingly, anti-IL-6 agents may potentially represent future promising therapies for the treatment of PP.

Haemophilus parasuis subunit vaccines based on native proteins with affinity to porcine transferrin prevent the expression of proinflammatory chemokines and cytokines in pigs

The expression of chemokines (CCL-2 and CXCL-8) and cytokines (IL-1α, IL-1β, IL-6, TNF-α, and IL-10) was evaluated by RT-qPCR in colostrum-deprived pigs vaccinated and challenged with Haemophilus parasuis serovar 5. Two vaccines containing native proteins with affinity to porcine transferrin (NPAPTim and NPAPTit) were tested, along with two control groups: one inoculated with PBS instead of antigen (challenge group (CHG)), and another one nonimmunized and noninfected (blank group). The use of NPAPTim and NPAPTit resulted in complete protection against H. parasuis (no clinical signs and/or lesions), and both vaccines were capable of avoiding the expression of the proinflammatory molecules to levels similar to physiological values in blank group. However, overexpression of all proinflammatory molecules was observed in CHG group, mainly in the target infection tissues (brain, lungs, and spleen). High expression of CCL-2, CXCL-8, IL-1α, IL-1β, and IL-6 can be considered one of the characteristics of H. parasuis infection by serovar 5.

IL-6-deficient mice show impaired inflammatory response in a model of myosin-induced experimental myositis

Inflammatory/immune reactions against muscle cells are responsible for the damage in idiopathic inflammatory myopathies. We investigated the role of IL-6, a cytokine known to contribute to local leukocyte accumulation, in a model of myosin-induced experimental myositis. After injection of rabbit myosin in CFA/pertussis toxin, normal mice develop clinically evident muscle deficit and damage, as demonstrated by myofiber necrosis and leukocyte infiltration, while IL-6-deficient mice have no clinical or histological signs of muscle damage. This study evidences that selective deficiency of IL-6 directly or indirectly hinders the local inflammatory response and its harmful effects in this model of muscle damage.

Necrosis is associated with IL-6 production but apoptosis is not

Due to loss of cell membrane integrity, necrotic cells passively release several cytosolic factors that can activate antigen presenting cells and other immune cells. In contrast, cells dying by apoptosis do not induce an inflammatory response. Here we show that necrotic cell death induced by several stimuli, such as TNF, anti-Fas or dsRNA, coincides with NF-kappaB-and p38MAPK-mediated upregulation and secretion of the pro-inflammatory cytokine IL-6. This event is greatly reduced or absent in conditions of apoptotic cell death induced by the same stimuli. This demonstrates that besides the capacity of necrotic cells to induce an inflammatory response due to leakage of cellular contents, necrotic dying cells themselves are involved in the expression and secretion of inflammatory cytokines. Moreover, inhibition of NF-kappaB and p38MAPK activation does not affect necrotic cell death in all conditions tested. This suggests that the activation of inflammatory pathways is distinct from the activation of necrotic cell death sensu strictu.