Evaluation of Adverse Effects of Resorbable Hyaluronic Acid Fillers: Determination of Macrophage Responses.

Resorbable tissue fillers for aesthetic purposes can induce severe complications including product migration, late swelling, and inflammatory reactions. The relation between product characteristics and adverse effects is not well understood. We hypothesized that the degree of cross-linking hyaluronic acid (HA) fillers was associated with the occurrence of adverse effects. Five experimental HA preparations similar to HA fillers were synthesized with an increasing degree of cross-linking. Furthermore, a series of commercial fillers (Perfectha®) was obtained that differ in degradation time based on the size of their particulate HA components. Cytotoxic responses and cytokine production by human THP-1-derived macrophages exposed to extracts of the evaluated resorbable HA fillers were absent to minimal. Gene expression analysis of the HA-exposed macrophages revealed the responses related to cell cycle control and immune reactivity. Our results could not confirm the hypothesis that the level of cross-linking in our experimental HA fillers or the particulate size of commercial HA fillers is related to the induced biological responses. However, the evaluation of cytokine induction and gene expression in macrophages after biomaterial exposure presents promising opportunities for the development of methods to identify cellular processes that may be predictive for biomaterial-induced responses in patients.

Gut microbiota controls the development of chronic pancreatitis: A critical role of short-chain fatty acids-producing Gram-positive bacteria.

Chronic pancreatitis (CP) is a progressive and irreversible fibroinflammatory disorder, accompanied by pancreatic exocrine insufficiency and dysregulated gut microbiota. Recently, accumulating evidence has supported a correlation between gut dysbiosis and CP development. However, whether gut microbiota dysbiosis contributes to CP pathogenesis remains unclear. Herein, an experimental CP was induced by repeated high-dose caerulein injections. The broad-spectrum antibiotics (ABX) and ABX targeting Gram-positive (G+) or Gram-negative bacteria (G-) were applied to explore the specific roles of these bacteria. Gut dysbiosis was observed in both mice and in CP patients, which was accompanied by a sharply reduced abundance for short-chain fatty acids (SCFAs)-producers, especially G+ bacteria. Broad-spectrum ABX exacerbated the severity of CP, as evidenced by aggravated pancreatic fibrosis and gut dysbiosis, especially the depletion of SCFAs-producing G+ bacteria. Additionally, depletion of SCFAs-producing G+ bacteria rather than G- bacteria intensified CP progression independent of TLR4, which was attenuated by supplementation with exogenous SCFAs. Finally, SCFAs modulated pancreatic fibrosis through inhibition of macrophage infiltration and M2 phenotype switching. The study supports a critical role for SCFAs-producing G+ bacteria in CP. Therefore, modulation of dietary-derived SCFAs or G+ SCFAs-producing bacteria may be considered a novel interventive approach for the management of CP.

Ohmyungsamycin promotes M1-like inflammatory responses to enhance host defence against Mycobacteroides abscessus infections.

Ohmyungsamycin A (OMS) is a newly identified cyclic peptide that exerts antimicrobial effects against Mycobacterium tuberculosis. However, its role in nontuberculous mycobacteria (NTMs) infections has not been clarified. Mycobacteroides abscessus (Mabc) is a rapidly growing NTM that has emerged as a human pathogen in both immunocompetent and immunosuppressed individuals. In this study, we demonstrated that OMS had significant antimicrobial effects against Mabc infection in both immunocompetent and immunodeficient mice, and in macrophages. OMS treatment amplified Mabc-induced expression of M1-related proinflammatory cytokines and inducible nitric oxide synthase, and significantly downregulated arginase-1 expression in murine macrophages. In addition, OMS augmented Mabc-mediated production of mitochondrial reactive oxygen species (mtROS), which promoted M1-like proinflammatory responses in Mabc-infected macrophages. OMS-induced production of mtROS and nitric oxide was critical for OMS-mediated antimicrobial responses during Mabc infections. Notably, the combination of OMS and rifabutin had a synergistic effect on the antimicrobial responses against Mabc infections in vitro, in murine macrophages, and in zebrafish models in vivo. Collectively, these data strongly suggest that OMS may be an effective M1-like adjunctive therapeutic against Mabc infections, either alone or in combination with antibiotics.

Humanized mice reveal a macrophage-enriched gene signature defining human lung tissue protection during SARS-CoV-2 infection.

The human immunological mechanisms defining the clinical outcome of SARS-CoV-2 infection remain elusive. This knowledge gap is mostly driven by the lack of appropriate experimental platforms recapitulating human immune responses in a controlled human lung environment. Here, we report a mouse model (i.e., HNFL mice) co-engrafted with human fetal lung xenografts (fLX) and a myeloid-enhanced human immune system to identify cellular and molecular correlates of lung protection during SARS-CoV-2 infection. Unlike mice solely engrafted with human fLX, HNFL mice are protected against infection, severe inflammation, and histopathological phenotypes. Lung tissue protection from infection and severe histopathology associates with macrophage infiltration and differentiation and the upregulation of a macrophage-enriched signature composed of 11 specific genes mainly associated with the type I interferon signaling pathway. Our work highlights the HNFL model as a transformative platform to investigate, in controlled experimental settings, human myeloid immune mechanisms governing lung tissue protection during SARS-CoV-2 infection.

7-Hydroxy Frullanolide, a sesquiterpene lactone, increases intracellular calcium amounts, lowers CD4+ T cell and macrophage responses, and ameliorates DSS-induced colitis.

Sesquiterpene lactones are a class of anti-inflammatory molecules obtained from plants belonging to the Asteraceae family. In this study, the effects of 7-hydroxy frullanolide (7HF), a sesquiterpene lactone, in inhibiting CD4+ T cell and peritoneal macrophage responses were investigated. 7HF, in a dose dependent manner, lowers CD69 upregulation, IL2 production and CD4+ T cell cycling upon activation with the combination of anti-CD3 and anti-CD28. Further mechanistic studies demonstrated that 7HF, at early time points, increases intracellular Ca2+ amounts, over and above the levels induced upon activation. The functional relevance of 7HF-induced Ca2+ increase was confirmed using sub-optimal amounts of BAPTA, an intracellular Ca2+ chelator, which lowers lactate and rescues CD4+ T cell cycling. In addition, 7HF lowers T cell cycling with the combination of PMA and Ionomycin. However, 7HF increases CD4+ T cell cycling with sub-optimal activating signals: only PMA or anti-CD3. Furthermore, LPS-induced nitrite and IL6 production by peritoneal macrophages is inhibited by 7HF in a Ca2+-dependent manner. Studies with Ca2+ channel inhibitors, Ruthenium Red and 2-Aminoethoxydiphenyl borate, lowers the inhibitory effects of 7HF on CD4+ T cell and macrophage responses. In silico studies demonstrated that 7HF binds to Ca2+ channels, TRPV1, IP3R and SERCA, which is mechanistically important. Finally, intraperitoneal administration of 7HF lowers serum inflammatory cytokines, IFNγ and IL6, and reduces the effects of DSS-induced colitis with respect to colon length and colon damage. Overall, this study sheds mechanistic light on the anti-inflammatory potential of 7HF, a natural plant compound, in lowering immune responses.

Anti-inflammatory effects of lenabasum, a cannabinoid receptor type 2 agonist, on macrophages from cystic fibrosis.

BACKGROUND: Lenabasum is an oral synthetic cannabinoid receptor type 2 agonist previously shown to reduce the production of key airway pro-inflammatory cytokines known to play a role in cystic fibrosis (CF). In a double-blinded, randomized, placebo-control phase 2 study, lenabasum lowered the rate of pulmonary exacerbation among patients with CF. The present study was undertaken to investigate anti-inflammatory mechanisms of lenabasum exhibits in CF macrophages. METHODS: We used monocyte-derived macrophages (MDMs) from healthy donors (n = 15), MDMs with CFTR inhibited with C-172 (n = 5) and MDMs from patients with CF (n = 4). Monocytes were differentiated to macrophages and polarized into classically activated (M1) macrophages by LPS or alternatively activated (M2) macrophages by IL-13 in presence or absence of lenabasum. RESULTS: Lenabasum had no effect on differentiation, polarization and function of macrophages from healthy individuals. However, in CF macrophages lenabasum downregulated macrophage polarization into the pro-inflammatory M1 phenotype and secretion of the pro-inflammatory cytokines IL-8 and TNF-α in a dose-dependent manner. An improvement in phagocytic activity was also observed following lenabasum treatment. Although lenabasum did not restore the impaired polarization of anti-inflammatory M2 macrophage, it reduced the levels of IL-13 and enhanced the endocytic function of CF MDMs. The effects of lenabasum on MDMs with CFTR inhibited by C-172 were not as obvious. CONCLUSION: In CF macrophages lenabasum modulates macrophage polarization and function in vitro in a way that would reduce inflammation in vivo. Further studies are warranted to determine the link between activating the CBR2 receptor and CFTR.

A Bioprocessed Polysaccharide from Lentinus edodes Mycelia Cultures with Turmeric Protects Chicks from a Lethal Challenge of Salmonella Gallinarum.

Our previous studies demonstrated that a bioprocessed polysaccharide (BPP) isolated from Lentinus edodes mushroom mycelia cultures supplemented with black rice bran can protect mice against Salmonella lipopolysaccharide-induced endotoxemia and reduce the mortality from Salmonella Typhimurium infection through upregulated T-helper 1 immunity. Here, we report that a BPP from L. edodes mushroom mycelia liquid cultures supplemented with turmeric (referred to as BPP-turmeric) alters chicken macrophage responses against avian-adapted Salmonella Gallinarum and protects chicks against a lethal challenge from Salmonella Gallinarum. In vitro analyses revealed that the water extract of BPP-turmeric (i) changed the protein expression or secretion profile of Salmonella Gallinarum, although it was not bactericidal, (ii) reduced the phagocytic activity of the chicken-derived macrophage cell line HD-11 when infected with Salmonella Gallinarum, and (iii) significantly activated the transcription expression of interleukin (IL)-1ß, IL-10, tumor necrosis factor α, and inducible nitric oxide synthase in response to various Salmonella infections, whereas it repressed that of IL-4, IL-6, interferon-ß, and interferon-γ. We also found that BPP-turmeric (0.1 g/kg of feed) as a feed additive provided significant protection to 1-day-old chicks infected with a lethal dose of Salmonella Gallinarum. Collectively, these results imply that BPP-turmeric contains biologically active component(s) that protect chicks against Salmonella Gallinarum infection, possibly by regulating macrophage immune responses. Further studies are needed to evaluate the potential efficacy of BPP-turmeric as a livestock feed additive for the preharvest control of fowl typhoid or foodborne salmonellosis.

Biocompatibility and potential of decellularized porcine small intestine to support cellular attachment and growth.

The aim of this study was to decellularize a 30 cm long segment of porcine small intestine, determine its in vivo behaviour and assess the type of immunological reaction it induces in a quantitative manner. A segment of porcine ileum up to 30 cm long, together with its attached vasculature, was decellularized via its mesenteric arcade as a single entity. The quality of the acellular scaffold was assessed histologically and using molecular tools. The host response to the scaffold was evaluated in a rodent model. Stereological techniques were incorporated into quantitative analysis of the phenotype of the macrophages infiltrating the scaffold in vivo. Lengths of ileal scaffold, together with its attached vasculature, were successfully decellularized, with no evidence of intact cells and DNA or collagen and GAGs overdegradation. Analysis of explants harvested over 2 months postimplantation revealed full-thickness recellularization and no signs of foreign body or immune reactions. Macrophage profiling proved that between weeks 4 and 8 in vivo there was a switch from an M1 (pro-inflammatory) to an M2 (pro-remodelling) type of response. We show here that the decellularization process results in a biocompatible and non-toxic matrix that upon implantation triggers cellular infiltration and angiogenesis, primarily characterized by a pro-remodelling type of mononuclear response, without inducing foreign body reaction or fibrosis.