Proinflammatory Stimuli Research Articles

Sensory innervation in the prostate and a role for calcitonin gene-related peptide in prostatic epithelial proliferation

IntroductionThe prostate is densely innervated like many visceral organs and glands. However, studies to date have focused on sympathetic and parasympathetic nerves and little attention has been given to the presence or function of sensory nerves in the prostate. Recent studies have highlighted a role for sensory nerves beyond perception of noxious stimuli, as anterograde release of neuropeptides from sensory nerves can affect vascular tone and local immune responses.MethodsTo identify the degree of sensory innervation in the prostate, we utilized state-of-the-art tissue clearing and microscopy to visualize sensory innervation in the different lobes of the mouse prostate. To determine whether sensory nerves have a role in regulating proliferation within the prostate, we used an intersectional genetic and toxin approach to ablate peptidergic sensory nerves systemically.ResultsWe found that sensory neurons are abundant in the prostate both in nerve bundles along the vasculature and as independent nerve fibers wrapped around prostatic acini in a net-like fashion. In addition to the dense innervation of the prostate, we found that Calca haploinsufficiency, the genotype control for our intersectional ablation model, results in a diminished level of Ki67 staining in the stromal compartment of the dorsal lobe and a diminishing Ki67 trend in other lobes.DiscussionThese findings suggest that sensory neurons might have developmental or homeostatic effects within the prostate. Further studies are warranted to assess the role of sensory neurons and the sensory neuropeptides on prostatic development and on proliferation in the presence of pro-inflammatory stimuli such as bacterial infection or tumor cells.

The microbiota metabolite, phloroglucinol, confers long-term protection against inflammation.

Phloroglucinol is a key byproduct of gut microbial metabolism that has been widely used as a treatment for irritable bowel syndrome. Here, we demonstrate that phloroglucinol tempers macrophage responses to pro-inflammatory pathogens and stimuli. In vivo, phloroglucinol administration decreases gut and extraintestinal inflammation in murine models of inflammatory bowel disease and systemic infection. The metabolite induces modest modifications in the microbiota. However, the presence of an active microbiota is required to preserve its anti-inflammatory activity. Remarkably, the protective effect of phloroglucinol lasts partially at least 6 months. Single-cell transcriptomic analysis of bone marrow progenitors demonstrates the capacity of the metabolite to induce long-lasting innate immune training in hematopoietic lineages, at least partially through the participation of the receptor and transcription factor, aryl hydrocarbon receptor (AhR). Phloroglucinol induces alterations in metabolic and epigenetic pathways that are most prevalent in upstream progenitors as hallmarks of central trained immunity. These data identify phloroglucinol as a dietary-derived compound capable of inducing central trained immunity and modulating the response of the host to inflammatory insults.

Central responses to peripheral inflammation may include decreased expression of key apoptotic protease caspase-3 in brainstem

Microglia activation by proinflammatory stimuli, including lipopolysaccharide (LPS), is considered among the risk factors for neurodegeneration, but the LPS treatment may also have a neuroprotective effect, which leads to further analysis of the relationship between microglial activation and regulators of cell death. In the present work, a comparative study was carried out on proteins expression of marker for activated microglia Iba-1 and the apoptotic executor protease caspase-3 in the brainstem and prefrontal cortex of rats injected intraperitoneally with endotoxin at different doses and schedules. One day after LPS at a dose of 0.5 mg/kg, single, the Iba-1 and caspase-3 expression in both structures did not differ from control values. Endotoxin administration fourfold at the same dose over 7 days (once every 2 days) led one day after the last injection to a significant increase in the Iba-1 level in the brainstem, which was accompanied by a significant decrease in the expression of caspase-3. The same effects in this structure were observed 7 days after a single injection of LPS at a higher dose of 5 mg/kg. In a 7-day experiment, in contrast to the brainstem, no changes in caspase-3 expression were found in the frontal cortex, and an increase in Iba-1 expression was observed only after a single injection of LPS at a high dose. The detected decrease of caspase-3 level in the brain stem under neuroinflammatory conditions may reflect the development of neuroprotective processes, especially important for the structure responsible for such key body functions as respiration, blood pressure and heartbeat.

Mitochondrial complex I inhibition enhances astrocyte responsiveness to pro-inflammatory stimuli

Inhibition of the mitochondrial oxidative phosphorylation (OXPHOS) system can lead to metabolic disorders and neurodegenerative diseases. In primary mitochondrial disorders, reactive astrocytes often accompany neuronal degeneration and may contribute to neurotoxic inflammatory cascades that elicit brain lesions. The influence of mitochondria to astrocyte reactivity as well as the underlying molecular mechanisms remain elusive. Here we report that mitochondrial Complex I dysfunction promotes neural progenitor cell differentiation into astrocytes that are more responsive to neuroinflammatory stimuli. We show that the SWItch/Sucrose Non-Fermentable (SWI/SNF/BAF) chromatin remodeling complex takes part in the epigenetic regulation of astrocyte responsiveness, since its pharmacological inhibition abrogates the expression of inflammatory genes. Furthermore, we demonstrate that Complex I deficient human iPSC-derived astrocytes negatively influence neuronal physiology upon cytokine stimulation. Together, our data describe the SWI/SNF/BAF complex as a sensor of altered mitochondrial OXPHOS and a downstream epigenetic regulator of astrocyte-mediated neuroinflammation.

USP30-AS1 Suppresses Colon Cancer Cell Inflammatory Response Through NF-κB/MYBBP1A Signaling.

Colorectal cancer (CRC) is one of the most prevalent malignancies worldwide and poses a significant threat to human health. Recent studies have underscored the crucial role of aberrant expression of long non-coding RNAs (lncRNAs) in the initiation and progression of CRC. In this study we identified that lncRNA USP30-AS1 is significantly downregulated in colorectal cancer tissues, particularly in the advanced stages of the disease. This downregulation correlates with reduced survival rates among patients. Enrichment analysis of genes associated with USP30-AS1 indicates a strong association with inflammatory responses. Notably, pro-inflammatory stimuli, including lipopolysaccharide (LPS) and tumor necrosis factor-α (TNF-α), were found to upregulate the expression of USP30-AS1. Functional assays demonstrated that the knockdown of USP30-AS1 resulted in increased degradation of IκBα protein and enhanced NF-κB transcriptional activity, as well as elevated expression levels of NF-κB downstream inflammatory molecules, including NLRP3, IL-1β, and IL-18. Conversely, ectopic expression of USP30-AS1 inhibited NF-κB transactivation. Mechanistically, USP30-AS1 interacts with MYBBP1A, a known regulator of NF-κB signaling. Notably, overexpression of MYBBP1A alleviated the stimulatory effect of USP30-AS1 knockdown on NF-κB activation. Collectively, these findings suggest that USP30-AS1 acts as a suppressor of colorectal cancer cell growth by modulating the MYBBP1A/NF-κB signaling pathway, thereby highlighting USP30-AS1 as a potential novel therapeutic target for colorectal cancer treatment.

Microprotein-encoding RNA regulation in cells treated with pro-inflammatory and pro-fibrotic stimuli

BackgroundRecent analysis of the human proteome via proteogenomics and ribosome profiling of the transcriptome revealed the existence of thousands of previously unannotated microprotein-coding small open reading frames (smORFs). Most functional microproteins were chosen for characterization because of their evolutionary conservation. However, one example of a non-conserved immunomodulatory microprotein in mice suggests that strict sequence conservation misses some intriguing microproteins.ResultsWe examine the ability of gene regulation to identify human microproteins with potential roles in inflammation or fibrosis of the intestine. To do this, we collected ribosome profiling data of intestinal cell lines and peripheral blood mononuclear cells and used gene expression of microprotein-encoding transcripts to identify strongly regulated microproteins, including several examples of microproteins that are only conserved with primates.ConclusionThis approach reveals a number of new microproteins worthy of additional functional characterization and provides a dataset that can be queried in different ways to find additional gut microproteins of interest.

Pericardial adipose tissue (PAT) as a cell model to assess patient responsiveness to docosahexaenoic acid (DHA) and eicopentaenoic acid (EPA)

Abstract Background The abundance of epicardial (EAT) and pericardial adipose tissue (PAT) is associated with several cardiac risk factors and a higher carotid intima-media thickness, with a potential contributory role to the development of atherosclerosis and coronary artery disease (CAD). Under conditions promoting obesity, both epicardial and pericardial adipose tissue undergo a metabolic shift, acquiring an inflammatory and pro-atherogenic phenotype. Addressing dysmetabolism and inflammation associated with EAT and PAT are a promising and innovative therapeutic approach for preventing coronary atherosclerosis. Recent data have highlighted a noteworthy association between the abundance of adipose tissue n-3 polyunsaturated fatty acids (PUFA) eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), as well as their ratio to the omega-6 FA arachidonic acid (AA), with a lower risk of myocardial infarction. Purpose To develop an efficient method for isolation of adipocytes from human PAT and evaluation of adipocyte response to DHA and EPA. Methods PAT samples were collected from 9 CAD patients, undergoing coronary artery bypass graft surgery and immediately processed before to assess more than 50 experimental conditions. Isolated adipocytes were morphologically and molecularly characterized. Cell responsiveness was evaluated by cell exposure to inflammatory stimuli, with or without variable amounts of DHA, EPA, or AA assessing a spectrum of gene expressions and pro-inflammatory functional activities. Results Pure cultures of pericardial adipocytes exhibited prolonged viability (beyond 72 hours). and retained responsiveness to pro-inflammatory and lipolytic stimuli, while also showing the capacity to activate the insulin signalling pathway. Cell exposure to DHA or EPA resulted in a downregulation of messenger (m)RNA expression for monocyte chemoattractant protein (MCP)-1, interleukin (IL)-6 and metalloproteinase (MMP)-9 (p<0.05) and in upregulation of uncoupling protein-(UCP)-1, UCP-2 and peroxisome proliferator-activated receptor (PPAR)γ (p< 0.05) (Figure 1). In line with mRNA expression, a significant reduction in both cytokines and MMP-9 protein release was observed (p<0.05) (Figure 2). These effects paralleled a significant incorporation of DHA and EPA into total cell lipids (p<0.05). Functionally, the cell supernatant from DHA- or EPA-conditioned cells displayed diminished ability to attract monocytes in chemotaxis assays. AA exhibited no such activities. Conclusion(s) In a novel cellular model of isolated and cultured adipocytes from PAT, DHA and EPA attenuated the inflammatory and dysmetabolic characteristics of this cardiac adipose tissue.

Analysis of correlations between behavioral parameters in the elevated plus maze and the levels of interleukin-1beta in blood plasma in rats

Peripheral cytokines may influence psychoemotional behavior, but the role of interleukin-1beta (IL-1beta) in altering anxiety and motor activity in response to inflammatory activation remains unclear. To clarify this issue, correlations between behavioral parameters in the elevated plus maze (EPM) test and plasma levels of IL-1beta after administration of the proinflammatory stimulus lipopolysaccharide (LPS) in different modes were analyzed in adult male rats. LPS in doses of 0.5 or 5 mg/kg, as well as physiological solution (control), were administered to rats intraperitoneally. The most pronounced behavioral effect 24 hours after a single injection was an endotoxin dose-dependent inhibition of the animals’ motor activity. After a dose of 5 mg/kg, increased anxious behavior was also noted every other day. The behavioral changes caused by the high dose of endotoxin were completely normalized after a week. The behavior of the animals one day after the end of repeated injections of LPS at a lower dose for a week (0.5 mg/kg; once every two days) also did not differ from the control. The inhibition of motor activity after LPS could be due to an increase in the level of IL-1beta in the blood plasma, as indicated by the identified significant negative correlations between IL-1beta and the corresponding behavioral parameters. No significant correlation was found between the peripheral level of IL-1beta and such a classic indicator of anxiety as the percentage of entries into the open arms of the maze. In general, the obtained results allow us to conclude that IL-1beta is an undoubted participant in the mechanism of the transient inhibitory effect of LPS on motor activity.

Crosstalk between macrophages and mesenchymal stem cells shape patterns of osteogenesis and immunomodulation in mineralized collagen scaffolds

Mesenchymal stem cells (MSCs) are highly plastic, with the capacity to differentiate into a spectrum of tissue-specific stromal cells. In the field of bone regeneration, MSCs have largely been considered for their osteogenic differentiation capacity. MSCs are increasingly being appreciated for their immunomodulatory potential following exposure to pro-inflammatory stimuli (licensing). Pro-inflammatory environments arise following bone injury via activation of resident immune cells like macrophages. We describe the use of a mineralized collagen scaffold as a bone-mimetic in vitro model to study the influence of paracrine versus direct cell-to-cell contact of THP-1 macrophages on MSC osteogenic and immunomodulatory potential. Paracrine stimuli from macrophages enhance MSC osteogenic and immunomodulatory potential via upregulation of key transcriptomic markers as well as via soluble biomolecule production. Direct co-culture of MSCs and macrophages decreased immunomodulatory potential in MSCs, especially for licensed MSCs, but enhanced matrix remodeling and expression of genes related to macrophage chemotaxis. These data demonstrate the significant effect macrophage-derived paracrine factors and direct contact have on MSC activity in a biomaterial model of bone regeneration. This work illuminates a critical need to further understand these processes in more clinically relevant cell models to inform biomaterial design.

Immunoregulatory Macrophages Modify Local Pulmonary Immunity and Ameliorate Hypoxic Pulmonary Hypertension.

Macrophages play a significant role in the onset and progression of vascular disease in pulmonary hypertension, and cell-based immunotherapies aimed at treating vascular remodeling are lacking. To evaluate the effect of pulmonary administration of macrophages modified to have an anti-inflammatory/proresolving phenotype in attenuating early pulmonary inflammation and progression of experimentally induced pulmonary hypertension. Mouse bone marrow-derived macrophages were polarized in vitro to a regulatory (M2reg) phenotype. M2reg profile and anti-inflammatory capacity were assessed in vitro upon lipopolysaccharide/IFNγ (interferon-γ) restimulation, before their administration to 8- to 12-week-old mice. M2reg protective effect was evaluated at early (2-4 days) and late (4 weeks) time points during hypoxia (8.5% O2) exposure. Levels of inflammatory markers were quantified in alveolar macrophages and whole lung, while pulmonary hypertension development was ascertained by right ventricular systolic pressure (RVSP) and right ventricular hypertrophy measurements. Bronchoalveolar lavage from M2reg-transplanted hypoxic mice was collected and its inflammatory potential evaluated on naive bone marrow-derived macrophages. M2reg macrophages expressing Tgfβ, Il10, and Cd206 demonstrated a stable anti-inflammatory phenotype in vitro, by downregulating the induction of proinflammatory cytokines and surface molecules (Cd86, Il6, and Tnfα) upon a subsequent proinflammatory stimulus. A single dose of M2reg attenuated hypoxic monocytic recruitment and perivascular inflammation. Early hypoxic lung and alveolar macrophage inflammation leading to pulmonary hypertension development was significantly reduced, and, importantly, M2reg attenuated right ventricular hypertrophy, right ventricular systolic pressure, and vascular remodeling at 4 weeks post-treatment. Adoptive transfer of M2reg halts the recruitment of monocytes and modifies the hypoxic lung microenvironment, potentially changing the immunoreactivity of recruited macrophages and restoring normal immune functionality of the lung. These findings provide new mechanistic insights into the diverse role of macrophage phenotype on lung vascular homeostasis that can be explored as novel therapeutic targets.

Mucosa-like differentiation of head and neck cancer cells is inducible and drives the epigenetic loss of cell malignancy

Head and neck squamous cell carcinoma (HNSCC) is a highly malignant disease with high death rates that have remained substantially unaltered for decades. Therefore, new treatment approaches are urgently needed. Human papillomavirus-negative tumors harbor areas of terminally differentiated tissue that are characterized by cornification. Dissecting this intrinsic ability of HNSCC cells to irreversibly differentiate into non-malignant cells may have tumor-targeting potential. We modeled the cornification of HNSCC cells in a primary spheroid model and analyzed the mechanisms underlying differentiation by ATAC-seq and RNA-seq. Results were verified by immunofluorescence using human HNSCC tissue of distinct anatomical locations. HNSCC cell differentiation was accompanied by cell adhesion, proliferation stop, diminished tumor-initiating potential in immunodeficient mice, and activation of a wound-healing-associated signaling program. Small promoter accessibility increased despite overall chromatin closure. Differentiating cells upregulated KRT17 and cornification markers. Although KRT17 represents a basal stem cell marker in normal mucosa, we confirm KRT17 to represent an early differentiation marker in HNSCC tissue. Cornification was frequently found surrounding necrotic areas in human tumors, indicating an involvement of pro-inflammatory stimuli. Indeed, inflammatory mediators activated the differentiation program in primary HNSCC cells. In HNSCC tissue, distinct cell differentiation states were found to create a common tissue architecture in normal mucosa and HNSCCs. Our data demonstrate a loss of cell malignancy upon faithful HNSCC cell differentiation, indicating that targeted differentiation approaches may be therapeutically valuable. Moreover, we describe KRT17 to be a candidate biomarker for HNSCC cell differentiation and early tumor detection.

Mesenchymal stromal cells can block palmitate training of macrophages via cyclooxygenase-2 and interleukin-1 receptor antagonist

Innate training of macrophages can be beneficial for the clearance of pathogens. However, for certain chronic conditions, innate training can have detrimental effects due to an excessive production of pro-inflammatory cytokines. Obesity is a condition that is associated with a range of increased pro-inflammatory training stimuli including the free fatty acid palmitate. Mesenchymal stromal cells (MSCs) are powerful immunomodulators and known to suppress inflammatory macrophages via a range of soluble factors. We show that palmitate training of murine bone-marrow-derived macrophages and human monocyte-derived macrophages (MDMs) results in an increased production of TNFα and IL-6 upon stimulation with lipopolysaccharide and is associated with epigenetic remodeling. Palmitate training led to metabolic changes, however, MSCs did not alter the metabolic profile of human MDMs. Using a transwell system, we demonstrated that human bone marrow MSCs block palmitate training in both murine and human macrophages suggesting the involvement of secreted factors. MSC disruption of the training process occurs through more than one pathway. Suppression of palmitate-enhanced TNFα production is associated with cyclooxygenase-2 activity in MSCs, while secretion of interleukin-1 receptor antagonist by MSCs is required to suppress palmitate-enhanced IL-6 production in MDMs.

The transcription regulators ZNF750 and LSD1/KDM1A dampen inflammation on the skin’s surface by silencing pattern recognition receptors

The surface of the skin is continually exposed to pro-inflammatory stimuli; however, it is unclear why it is not constantly inflamed due to this exposure. Here, we showed undifferentiated keratinocytes residing in the deep epidermis could trigger a strong inflammatory response due to their high expression of pattern recognition receptors (PRRs) that detect damage or pathogens. As keratinocytes differentiated, they migrated outward toward the surface of the skin and decreased their PRR expression, which led to dampened immune responses. ZNF750, a transcription factor expressed only in differentiated keratinocytes, recruited the histone demethylase KDM1A/LSD1 to silence genes coding for PRRs (TLR3, IFIH1/MDA5, and DDX58/RIG1). Loss of ZNF750 or KDM1A in human keratinocytes or mice resulted in sustained and excessive inflammation resembling psoriatic skin, which could be restored to homeostatic conditions upon silencing of TLR3. Our findings explain how the skin's surface prevents excessive inflammation through ZNF750- and KDM1A-mediated suppression of PRRs.

Inflammatory Mediators Suppress FGFR2 Expression in Human Keratinocytes to Promote Inflammation.

Fibroblast growth factors (FGFs) are key orchestrators of development, tissue homeostasis and repair. FGF receptor (FGFR) deficiency in mouse keratinocytes causes an inflammatory skin phenotype with similarities to atopic dermatitis, but the human relevance is unclear. Therefore, we generated human keratinocytes with a CRISPR/Cas9-induced knockout of FGFR2. Loss of this receptor promoted the expression of interferon-stimulated genes and pro-inflammatory cytokines under homeostatic conditions and in particular in response to different inflammatory mediators. Expression of FGFR2 itself was strongly downregulated in cultured human keratinocytes exposed to various pro-inflammatory stimuli. This is relevant invivo, because bioinformatics analysis of bulk and single-cell RNA-seq data showed strongly reduced expression of FGFR2 in lesional skin of atopic dermatitis patients, which likely aggravates the inflammatory phenotype. These results reveal a key function of FGFR2 in human keratinocytes in the suppression of inflammation and suggest a role of FGFR2 downregulation in the pathogenesis of atopic dermatitis and possibly other inflammatory diseases.

CSF1 is expressed by the intestinal epithelial cells to regulate Mφ macrophages and maintain epithelial homeostasis and is downregulated in neonates with necrotizing enterocolitis

BackgroundColony stimulating factor 1 (CSF1) is generally expressed by immune cells in response to pro-inflammatory stimuli. The CSF1 receptor (CSFR) is activated by CSF1, and plays a key role in macrophage homeostasis. Furthermore, the CSF1R+ macrophages maintain homeostasis in the intestinal epithelium. The aim of this study was to explore the functions of CSF1-expressing and CSF1R+ macrophages in necrotizing enterocolitis (NEC), which commonly affects the ileum of neonates.MethodsIn-situ CSF1 expression in the intestines of neonates with NEC or intestinal atresia (n = 4 each) was detected by immunofluorescence staining. The CSF1 levels in the intestinal crypt-derived organoid cultures were measured by ELISA. Peripheral blood monocyte-derived Mφ macrophages were co-cultured with the organoids and stimulated with lipopolysaccharide (LPS) to mimic the inflamed state of the ileum in NEC patients.ResultsCSF1 was expressed in the intestinal epithelial cells of the fetal and neonatal samples, but suppressed in the NEC samples. Furthermore, CSF1 expression was downregulated in the intestinal crypt-derived organoids by LPS. CSF1R+ macrophages were detected near the intestinal crypts in the non-inflamed intestines but were absent in tissues obtained from pediatric NEC patients. Peripheral blood monocyte-derived macrophages promoted intestinal organoid proliferation in vitro following CSF1 stimulation. Finally, low concentrations of LPS slightly enhanced the proliferation of organoids co-cultured with the macrophages, whereas higher doses had a significant inhibitory effect.ConclusionsIntestinal epithelial cells express CSF1 to regulate the resident macrophages, maintain epithelial homeostasis, and resist infection. The abundant CSF1R+ macrophages in the fetal intestine may overexpress TNF-α upon activation of the TLR4/NF-κB pathway, resulting in epithelial damage and NEC induction.

Systemic low-dose anti-fibrotic treatment attenuates ovarian aging in the mouse.

The female reproductive system is one of the first to age in humans, resulting in infertility and endocrine disruptions. The aging ovary assumes a fibro-inflammatory milieu which negatively impacts gamete quantity and quality as well as ovulation. Here, we tested whether the systemic delivery of anti-inflammatory (Etanercept) or anti-fibrotic (Pirfenidone) drugs attenuates ovarian aging in mice. We first evaluated the ability of these drugs to decrease the expression of fibro-inflammatory genes in primary ovarian stromal cellstreated with a pro-fibrotic or a pro-inflammatory stimulus. Whereas Etanercept did not block Tnf expression in ovarian stromal cells, Pirfenidone significantly reduced Col1a1 expression. We then tested Pirfenidone in vivo where the drug was delivered systemically via mini-osmotic pumps for 6weeks. Pirfenidone mitigated the age-dependent increase in ovarian fibrosis without impacting overall health parameters. Ovarian function was improved in Pirfenidone-treated mice as evidenced by increased follicle and corpora lutea number, AMH levels, and improved estrous cyclicity. Transcriptomic analysis revealed that Pirfenidone treatment resulted in an upregulation of reproductive function-related genes at 8.5months and a downregulation of inflammatory genes at 12months of age. These findings demonstrate that reducing the fibroinflammatory ovarian microenvironment improves ovarian function, thereby supporting modulating the ovarian environment as a therapeutic avenue to extend reproductive longevity.

A Pro-Inflammatory Stimulus versus Extensive Passaging of DITNC1 Astrocyte Cultures as Models to Study Astrogliosis.

Astrogliosis is a process by which astrocytes, when exposed to inflammation, exhibit hypertrophy, motility, and elevated expression of reactivity markers such as Glial Fibrillar Acidic Protein, Vimentin, and Connexin43. Since 1999, our laboratory in Chile has been studying molecular signaling pathways associated with "gliosis" and has reported that reactive astrocytes upregulate Syndecan 4 and αVβ3 Integrin, which are receptors for the neuronal glycoprotein Thy-1. Thy-1 engagement stimulates adhesion and migration of reactive astrocytes and induces neurons to retract neurites, thus hindering neuronal network repair. Reportedly, we have used DITNC1 astrocytes and neuron-like CAD cells to study signaling mechanisms activated by the Syndecan 4-αVβ3 Integrin/Thy-1 interaction. Importantly, the sole overexpression of β3 Integrin in non-reactive astrocytes turns them into reactive cells. In vitro, extensive passaging is a simile for "aging", and aged fibroblasts have shown β3 Integrin upregulation. However, it is not known if astrocytes upregulate β3 Integrin after successive cell passages. Here, we hypothesized that astrocytes undergoing long-term passaging increase β3 Integrin expression levels and behave as reactive astrocytes without needing pro-inflammatory stimuli. We used DITNC1 cells with different passage numbers to study reactivity markers using immunoblots, immunofluorescence, and astrocyte adhesion/migration assays. We also evaluated β3 Integrin levels by immunoblot and flow cytometry, as well as the neurotoxic effects of reactive astrocytes. Serial cell passaging mimicked the effects of inflammatory stimuli, inducing astrocyte reactivity. Indeed, in response to Thy-1, β3 Integrin levels, as well as cell adhesion and migration, gradually increased with multiple passages. Importantly, these long-lived astrocytes expressed and secreted factors that inhibited neurite outgrowth and caused neuronal death, just like reactive astrocytes in culture. Therefore, we describe two DITNC1 cell types: a non-reactive type that can be activated with Tumor Necrosis Factor (TNF) and another one that exhibits reactive astrocyte features even in the absence of TNF treatment. Our results emphasize the importance of passage numbers in cell behavior. Likewise, we compare the pro-inflammatory stimulus versus long-term in-plate passaging of cell cultures and introduce them as astrocyte models to study the reactivity process.

Cardiac fat adipocytes: An optimized protocol for isolation of ready-to-use mature adipocytes from human pericardial adipose tissue

A better understanding of the pathophysiology of cardiac fat depots is crucial to describe their role in the development of cardiovascular diseases. To this end, we have developed a method to isolate mature fat cells from the pericardial adipose tissue (PAT), the most accessible cardiac fat depot during cardiac surgery. Using enzymatic isolation, we were able to successfully obtain mature fat cells together with the corresponding cells of the stromal vascular fraction (SVF). We subjected the PAT adipocytes to thorough morphological and molecular characterization, including detailed fatty acid profiling, and simultaneously investigated their reactivity to external stimuli. Our approach resulted in highly purified fat cells with sustained viability for up to 72 h after explantation. Remarkably, these adipocytes responded to multiple challenges, including pro-inflammatory and metabolic stimuli, indicating their potential to trigger a pro-inflammatory response and modulate endothelial cell behavior. Furthermore, we have created conditions to maintain whole PAT in culture and preserve their viability and reactivity to external stimuli. The efficiency of cell recovery combined with minimal dedifferentiation underscores the promise for future applications as a personalized tool for screening and assessing individual patient responses to drugs and supplements or nutraceuticals.

HIF-α signaling regulates the macrophage inflammatory response during Leishmania major infection.

Cutaneous leishmaniasis (CL) contributes significantly to the global burden of neglected tropical diseases, with 12 million people currently infected with Leishmania parasites. CL encompasses a range of disease manifestations, from self-healing skin lesions to permanent disfigurations. Currently there is no vaccine available, and many patients are refractory to treatment, emphasizing the need for new therapeutic targets. Previous work demonstrated macrophage HIF-α-mediated lymphangiogenesis is necessary to achieve efficient wound resolution during murine L. major infection. Here, we investigate the role of macrophage HIF-α signaling independent of lymphangiogenesis. We sought to determine the relative contributions of the parasite and the host-mediated inflammation in the lesional microenvironment to myeloid HIF-α signaling. Because HIF-α activation can be detected in infected and bystander macrophages in leishmanial lesions, we hypothesize it is the host's inflammatory response and microenvironment, rather than the parasite, that triggers HIF-α activation. To address this, macrophages from mice with intact HIF-α signaling (LysM Cre ARNT f/+ ) or mice with deleted HIF-α signaling (LysM Cre ARNT f/f ) were subjected to RNASequencing after L. major infection and under pro-inflammatory stimulus. We report that L. major infection alone is enough to induce some minor HIF-α-dependent transcriptomic changes, while infection with L. major in combincation with pro-inflammatory stimuli induces numerous transcriptomic changes that are both dependent and independent of HIF-α signaling. Additionally, by coupling transcriptomic analysis with several pathway analyses, we found HIF-α suppresses pathways involved in protein translation during L. major infection in a pro-inflammatory environment. Together these findings show L. major induces a HIF-α-dependent transcriptomic program, but HIF-α only suppresses protein translation in a pro-inflammatory environment. Thus, this work indicates the host inflammatory response, rather than the parasite, largely contributes to myeloid HIF-α signaling during Leishmania infection.

Downregulation of Fidgetin-Like 2 Increases Microglial Function: The Relationship Between Microtubules, Morphology, and Activity.

The microtubule cytoskeleton regulates microglial morphology, motility, and effector functions. The microtubule-severing enzyme, fidgetin-like 2 (FL2), negatively regulates cell motility and nerve regeneration, making it a promising therapeutic target for central nervous system injury. Microglia perform important functions in response to inflammation and injury, but how FL2 affects microglia is unclear. In this study, we investigated the role of FL2 in microglial morphology and injury responses in vitro. We first determined that the pro-inflammatory stimulus, lipopolysaccharide (LPS), induced a dose- and time-dependent reduction in FL2 expression associated with reduced microglial ramification. We then administered nanoparticle-encapuslated FL2 siRNA to knockdown FL2 and assess microglial functions compared to negative control siRNA and vehicle controls. Time-lapse live-cell microscopy showed that FL2 knockdown increased the velocity of microglial motility. After incubation with fluorescently labeled IgG-opsonized beads, FL2 knockdown increased phagocytosis. Microglia were exposed to low-dose LPS after nanoparticle treatment to model injury-induced cytokine secretion. FL2 knockdown enhanced LPS-induced cytokine secretion of IL-1α, IL-1β, and TNFα. These results identify FL2 as a regulator of microglial morphology and suggest that FL2 can be targeted to increase or accelerate microglial injury responses.