P21 facilitates macrophage chemotaxis by promoting CCL7 in the lung epithelial cell lines treated with radiation and bleomycin.

BACKGROUND: Interstitial lung diseases (ILDs) can be induced and even exacerbated by radiotherapy in thoracic cancer patients. The roles of immune responses underlying the development of these severe lung injuries are still obscure and need to be investigated. METHODS: A severe lung damage murine model was established by delivering 16 Gy X-rays to the chest of mice that had been pre-treated with bleomycin (BLM) and thus hold ILDs. Bioinformatic analyses were performed on the GEO datasets of radiation-induced lung injury (RILI) and BLM-induced pulmonary fibrosis (BIPF), and RNA-sequencing data of the severely damaged lung tissues. The screened differentially expressed genes (DEGs) were verified in lung epithelial cell lines by qRT-PCR assay. The injured lung tissue pathology was analyzed with H&E and Masson's staining, and immunohistochemistry staining. The macrophage chemotaxis and activity promoted by the stressed epithelial cells were determined by using a cell co-culture system. The expressions of p21 in MLE-12 and Beas-2B cells were detected by qRT-PCR, western blot, and immunofluorescence. The concentration of CCL7 in cell supernatant was measured by ELISA assay. In some experiments, Beas-2B cells were transfected with p21-siRNA or CCL7-siRNA before irradiation and/or BLM treatment. RESULTS: After the treatment of irradiation and/or BLM, the inflammatory and immune responses, chemokine-mediated signaling pathways were steadily activated in the severely injured lung, and p21 was screened out by the bioinformatic analysis and further verified to be upregulated in both mouse and human lung epithelial cell lines. The expression of P21 was positively correlated with macrophage infiltration in the injured lung tissues. Co-culturing with stressed Beas-2B cells or its conditioned medium containing CCL7 protein, U937 macrophages were actively polarized to M1-phase and their migration ability was obviously increased along with the damage degree of Beas-2B cells. Furthermore, knockdown p21 reduced CCL7 expression in Beas-2B cells and then decreased the chemotaxis of co-cultured macrophages. CONCLUSIONS: P21 promoted CCL7 release from the severely injured lung epithelial cell lines and contributed to the macrophage chemotaxis in vitro, which provides new insights for better understanding the inflammatory responses in lung injury.

CCL7 and TGF-ß secreted by MSCs play opposite roles in regulating CRC metastasis in a KLF5/CXCL5-dependent manner.

CXCL5 is overexpressed in colorectal cancer (CRC) and promotes distant metastasis and angiogenesis of tumors; however, the underlying mechanism that mediates CXCL5 overexpression in CRC remains unclear. Here, we successfully extracted and identified primary mesenchymal stromal cells (MSCs) and verified the promoting effects of tumor-associated MSCs on CRC proliferation and metastasis in vivo and in vitro. We found that MSCs not only promoted the expression of CXCL5 by secreting CCL7 but also secreted TGF-ß to inhibit this process. After secretion, CCL7/CCR1 activated downstream CBP/P300 to acetylate KLF5 to promote CXCL5 transcription, while TGF-ß reversed the effect of KLF5 on transcription activation by regulating SMAD4. Taken together, our results indicate that MSCs in the tumor microenvironment promoted the progression and metastasis of CRC and regulated the expression of CXCL5 in CRC cells by secreting CCL7 and TGF-ß. KLF5 is the key site of these processes and plays a dual role in CXCL5 regulation. MSCs and their secreted factors may serve as potential therapeutic targets in the tumor environment.

HDAC2 exacerbates rheumatoid arthritis progression via the IL-17-CCL7 signaling pathway.

Histone deacetylases (HDACs) have been reported to regulate the immune response in rheumatoid arthritis (RA). The current study aimed to explore key HDACs and their molecular mechanism in RA. First, the expression of HDAC1, HDAC2, HDAC3 and HDAC8 in RA synovial tissue was determined by qRT-PCR. The effects of HDAC2 on the proliferation, migration, invasion, and apoptosis of fibroblast-like synoviocytes (FLS) in vitro were studied. Furthermore, collagen-induced arthritis (CIA) rat models were established to evaluate the severity of arthritis in joints, and the levels of inflammatory factors were examined by immunohistochemistry staining, ELISA, and qRT-PCR. Transcriptome sequencing was used to screen differentially expressed genes (DEGs) with HDAC2 silencing in the synovial tissue of CIA rat, and downstream signaling pathways were predicted by enrichment analysis. The results showed that HDAC2 was highly expressed in the synovial tissue of RA patients and CIA rats. Overexpressed HDAC2 promoted FLS proliferation, migration, and invasion and inhibited FLS apoptosis in vitro, resulting in secretion of inflammatory factors and RA exacerbation in vivo. There were 176 DEGs, including 57 downregulated and 119 upregulated genes, after silencing HDAC2 in CIA rats. DEGs were primarily enriched in Platinum drug resistance, IL-17 as well as the PI3K-Akt signaling pathways. CCL7, which was implicated in the IL-17 signaling pathway, was downregulated after HDAC2 silencing. Furthermore, CCL7 overexpression aggravated the development of RA, which was demonstrated to be effectively attenuated by HDAC2 suppression. In conclusion, this study demonstrated that HDAC2 exacerbated the progression of RA by regulating the IL-17-CCL7 signaling pathway, suggesting that HDAC2 may be a promising therapeutic target for RA treatment.

HIF1α/CCL7/KIAA1199 axis mediates hypoxia-induced gastric cancer aggravation and glycolysis alteration.

Gastric cancer is a common digestion tumor with high malignant severity and prevalence. Emerging studies reported C-C motif chemokine ligand 7 (CCL7) as a regulator of various tumor diseases. Our research explored the function and underlying mechanism of CCL7 during gastric cancer development. RT-qPCR, Western blot and other datasets were employed to evaluate CCL7 expression in tissues and cells. Kaplan-Meier and Cox regression analyses were recruited to evaluate the correlations between CCL7 expression and patients' survival or clinical features. A loss-of-function assay was performed to evaluate the function of CCL7 in gastric cancer. 1% O2 was utilized to mimic hypoxic condition. KIAA1199 and HIF1α were included in the regulatory mechanism. The results showed that CCL7 was up-regulated and its high expression was correlated with poor survival of gastric cancer patients. Depressing CCL7 attenuated proliferation, migration, invasion, and induced apoptosis of gastric cancer cells. Meanwhile, CCL7 inhibition weakened hypoxia-induced gastric cancer aggravation. Besides, KIAA1199 and HIF1α were involved in the mechanism of CCL7-mediated gastric cancer aggravation under hypoxia. Our research identified CCL7 as a novel tumor-activator in gastric cancer pathogenesis and hypoxia-induced tumor aggravation was regulated by HIF1α/CCL7/KIAA1199 axis. The evidence may provide a novel target for gastric cancer treatment.

CCL7 playing a dominant role in recruiting early OCPs to facilitate osteolysis at metastatic site of colorectal cancer.

BACKGROUND: Chemoattractant is critical to recruitment of osteoclast precursors and stimulates tumor bone metastasis. However, the role of chemoattractant in bone metastasis of colorectal cancer (CRC) is still unclear. METHODS: Histochemistry analysis and TRAP staining were utilized to detect the bone resorption and activation of osteoclasts (OCs) after administration of CCL7 neutralizing antibody or CCR1 siRNA. qRT-PCR analysis and ELISA assay were performed to detect the mRNA level and protein level of chemoattractant. BrdU assay and Tunel assay were used to detect the proliferation and apoptosis of osteoclast precursors (OCPs). The migration of OCPs was detected by Transwell assay. Western blots assay was performed to examine the protein levels of pathways regulating the expression of CCL7 or CCR1. RESULTS: OCPs-derived CCL7 was significantly upregulated in bone marrow after bone metastasis of CRC. Blockage of CCL7 efficiently prevented bone resorption. Administration of CCL7 promoted the migration of OCPs. Lactate promoted the expression of CCL7 through JNK pathway. In addition, CCR1 was the most important receptor of CCL7. CONCLUSION: Our study indicates the essential role of CCL7-CCR1 signaling for recruitment of OCPs in early bone metastasis of CRC. Targeting CCL7 or CCR1 could restore the bone volume, which could be a potential therapeutical target. Video Abstract.

CCL7 Signaling in the Tumor Microenvironment.

The tumor microenvironment is the primary location in which tumor cells and the host immune system interact. There are many physiological, biochemical, cellular mechanisms in the neighbor of tumor which is composed of various cell types. Interactions of chemokines and chemokine receptors can recruit immune cell subsets into the tumor microenvironment. These interactions can modulate tumor progression and metastasis. In this chapter, we will focus on chemokine (C-C motif) ligand 7 (CCL7) that is highly expressed in the tumor microenvironment of various cancers, including colorectal cancer, breast cancer, oral cancer, renal cancer, and gastric cancer. We reviewed how CCL7 can affect cancer immunity and tumorigenesis by describing its regulation and roles in immune cell recruitment and stromal cell biology.

The potential of Atorvastatin for chronic lung diseases therapy.

Atorvastatin (ATO) is of the statin class and is used as an orally administered lipid-lowering drug. ATO is a reversible synthetic competitive inhibitor of 3-hydroxy-3-methyl-glutaryl-CoA (HMG-CoA) reductase thus leading to a reduction in cholesterol synthesis. It has recently been demonstrated that ATO has different pharmacological actions, which are unrelated to its lipid-lowering effects and has the ability to treat chronic airway diseases. This paper reviews the potential of ATO as an anti-inflammatory, antioxidant, and anti-proliferative agent after oral or inhaled administration. This paper discusses the advantages and disadvantages of using ATO under conditions associated with those found in the airways. This treatment could potentially be used to support the formulating of ATO as an inhaler for the treatment of chronic respiratory diseases.

miR-23b Suppresses Leukocyte Migration and Pathogenesis of Experimental Autoimmune Encephalomyelitis by Targeting CCL7.

MicroRNAs (miRNAs) are small, non-coding RNAs involved in immune response regulation. Specific miRNAs have been linked to the development of various autoimmune diseases; however, their contribution to the modulation of CNS-directed cellular infiltration remains unclear. In this study, we found that miR-23b, in addition to its reported functions in the suppression of IL-17-associated autoimmune inflammation, halted the progression of experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis (MS), by directly inhibiting the migration of pathogenic leukocytes to the CNS. We demonstrated that miR-23b was specifically decreased during the acute phase of EAE and that overexpression of miR-23b resulted in a defect in leukocyte migration and strong resistance to EAE. Furthermore, we found that miR-23b suppressed leukocyte migration of EAE by targeting CCL7, a chemokine that attracts monocytes during inflammation and metastasis. Finally, in the adoptive transfer model, miR-23b reduced the severity of EAE by inhibiting the migration of pathogenic T cells to the CNS rather than diminishing the encephalitogenesis of T cells. Taken together, our results characterize a novel aspect of miR-23b function in leukocyte migration, and they identify miR-23b as a potential therapeutic target in the amelioration of MS and likely other autoimmune diseases.

Effect of Chemokine (C-C Motif) Ligand 7 (CCL7) and Its Receptor (CCR2) Expression on Colorectal Cancer Behaviors.

Colorectal cancer is the source of one of the most common cancer-related deaths worldwide, where the main cause of patient mortality remains metastasis. The aim of this study was to determine the role of CCL7 (chemokine (C-C motif) ligand 7) in tumor progression and finding whether it could predict survival of colorectal cancer patients. Initially, our study focused on the crosstalk between mesenchymal stem cells (MSCs) and CT26 colon carcinoma cells and resulted in identifying CCL7 as a chemokine upregulated in CT26 colon cancer cells cocultured with MSCs, compared with CT26 in monoculture in vitro. Moreover, we showed that MSCs enhance CT26 tumor cell proliferation and migration. We analyzed the effect of CCL7 overexpression on tumor progression in a murine CT26 model, where cells overexpressing CCL7 accelerated the early phase of tumor growth and caused higher lung metastasis rates compared with control mice. Microarray analysis revealed that tumors overexpressing CCL7 had lower expression of immunoglobulins produced by B lymphocytes. Additionally, using Jh mutant mice, we confirmed that in the CT26 model, CCL7 has an immunoglobulin-, and thereby, B-cell-dependent effect on metastasis formation. Finally, higher expression of CCL7 receptor CCR2 (C-C chemokine receptor type 2) was associated with shorter overall survival of colorectal cancer patients. Altogether, we showed that CCL7 is essentially involved in the progression of colorectal cancer in a CT26 mouse model and that the expression of its receptor CCR2 could be related to a different outcome pattern of patients with colorectal carcinoma.

Multiple glycosaminoglycan-binding epitopes of monocyte chemoattractant protein-3/CCL7 enable it to function as a non-oligomerizing chemokine.

The interaction of chemokines with glycosaminoglycans (GAGs) facilitates the formation of localized chemokine gradients that provide directional signals for migrating cells. In this study, we set out to understand the structural basis and impact of the differing oligomerization propensities of the chemokines monocyte chemoattractant protein (MCP)-1/CCL2 and MCP-3/CCL7 on their ability to bind GAGs. These chemokines provide a unique comparison set because CCL2 oligomerizes and oligomerization is required for its full in vivo activity, whereas CCL7 functions as a monomer. To identify the GAG-binding determinants of CCL7, an unbiased hydroxyl radical footprinting approach was employed, followed by a focused mutagenesis study. Compared with the size of the previously defined GAG-binding epitope of CCL2, CCL7 has a larger binding site, consisting of multiple epitopes distributed along its surface. Furthermore, surface plasmon resonance (SPR) studies indicate that CCL7 is able to bind GAGs with an affinity similar to CCL2 but higher than the non-oligomerizing variant, CCL2(P8A), suggesting that, in contrast to CCL2, the large cluster of GAG-binding residues in CCL7 renders oligomerization unnecessary for high affinity binding. However, the affinity of CCL7 is more sensitive than CCL2 to the density of heparan sulfate on the SPR surfaces; this is likely due to the inability of CCL7 to oligomerize because CCL2(P8A) also binds significantly less tightly to low than high density heparan sulfate surfaces compared with CCL2. Together, the data suggest that CCL7 and CCL2 are non-redundant chemokines and that GAG chain density may provide a mechanism for regulating the accumulation of chemokines on cell surfaces.

CCL7 contributes to the TNF-alpha-dependent inflammation of lesional psoriatic skin.

Chemokines are small chemotactic proteins that have a crucial role in leukocyte recruitment into tissue. Targeting these mediators has been suggested as a potential therapeutic option in inflammatory skin diseases such as psoriasis. Using quantitative RT-PCR, we found CCL7, a chemokine ligand known to interact with multiple C-C chemokine receptors, to be markedly increased in lesional psoriasis as opposed to atopic dermatitis, lichen planus, non-lesional psoriatic and normal control skin. Surprisingly, this increase in CCL7 mRNA expression exceeded that of all other chemokines investigated, and keratinocytes and dermal blood endothelial cells were identified as its likely cellular sources. In an imiquimod-induced psoriasis-like mouse model, CCL7 had a profound impact on myeloid cell inflammation as well as on the upregulation of key pro-psoriatic cytokines such as CCL20, IL-12p40 and IL-17C, while its blockade led to an increase in the antipsoriatic cytokine IL-4. In humans receiving the TNF-α-blocker infliximab, CCL7 was downregulated in lesional psoriatic skin already within 16 hours after a single intravenous infusion. These data suggest that CCL7 acts as a driver of TNF-α-dependent Th1/Th17-mediated inflammation in lesional psoriatic skin.

T cell-derived microvesicles induce mast cell production of IL-24: relevance to inflammatory skin diseases.

BACKGROUND: It has recently been shown that microvesicles derived from activated T cells can stimulate human mast cells (MCs) to degranulate and release several cytokines. OBJECTIVE: The aim of this study was to characterize microvesicle-induced MC expression patterns. Through identification of unique cytokine and chemokine expression, we attempted to reveal pathogenetic roles for this pathway of MC activation. METHODS: T cell-derived microvesicles were labeled with PKH67 to allow visualization of their interaction with human MCs. Consequent gene expression profiling was studied by using a whole-genome microarray and analyzed for identification of cellular pathway clusters. Expression of 3 selected genes, chemokine (C-C motif) ligand 3 (CCL3), chemokine (C-C motif) ligand 7 (CCL7), and IL24, was validated by means of quantitative RT-PCR and specific ELISA. IL24, which has not been recognized heretofore in MCs, was also tested for its effect on keratinocyte signal transducer and activator of transcription 3 phosphorylation and for its presence in MCs in psoriatic skin lesions. RESULTS: Uptake and internalization of activated T cell-derived microvesicles into human MCs occurred within 24 hours. Microvesicles induced the upregulation of several clusters of genes, notably those that are cytokine related. Among these, IL24 appeared to be a hallmark of microvesicle-induced activation. MC-derived IL-24, in turn, activates keratinocytes in vitro, as manifested by signal transducer and activator of transcription 3 (STAT3) phosphorylation, and is produced in MCs within psoriatic lesions. CONCLUSION: Production of IL-24 is a unique feature of microvesicle-induced MC activation because its production by these cells has not been recognized thus far. We propose that this MC-derived cytokine might contribute to the pathologic findings in T cell-mediated skin inflammation.

Single-target RNA interference for the blockade of multiple interacting proinflammatory and profibrotic pathways in cardiac fibroblasts.

Therapeutic targets of broad relevance are likely located in pathogenic pathways common to disorders of various etiologies. Screening for targets of this type revealed CCN genes to be consistently upregulated in multiple cardiomyopathies. We developed RNA interference (RNAi) to silence CCN2 and found this single-target approach to block multiple proinflammatory and profibrotic pathways in activated primary cardiac fibroblasts (PCFBs). The RNAi-strategy was developed in murine PCFBs and then investigated in "individual" human PCFBs grown from human endomyocardial biopsies (EMBs). Screening of short hairpin RNA (shRNA) sequences for high silencing efficacy and specificity yielded RNAi adenovectors silencing CCN2 in murine or human PCFBs, respectively. Comparison of RNAi with CCN2-modulating microRNA (miR) vectors expressing miR-30c or miR-133b showed higher efficacy of RNAi. In murine PCFBs, CCN2 silencing resulted in strongly reduced expression of stretch-induced chemokines (Ccl2, Ccl7, Ccl8), matrix metalloproteinases (MMP2, MMP9), extracellular matrix (Col3a1), and a cell-to-cell contact protein (Cx43), suggesting multiple signal pathways to be linked to CCN2. Immune cell chemotaxis towards CCN2-depleted PCFBs was significantly reduced. We demonstrate here that this RNAi strategy is technically applicable to "individual" human PCFBs, too, but that these display individually strikingly different responses to CCN2 depletion. Either genomically encoded factors or stable epigenetic modification may explain different responses between individual PCFBs. The new RNAi approach addresses a key regulator protein induced in cardiomyopathies. Investigation of this and other molecular therapies in individual human PCBFs may help to dissect differential pathogenic processes between otherwise similar disease entities and individuals.

High coexpression of CCL2 and CX3CL1 is gender-specifically associated with good prognosis in soft tissue sarcoma patients.

Chemokines are involved in both the negative and positive regulation of inflammatory processes, angiogenesis and cancer/cancer stem cell proliferation as well as the chemoattraction of tumor cells to metastatic sites. The aim of this study was to measure the mRNA expression levels of three chemokines, CCL2, CCL7 and CX3CL1, in soft tissue sarcomas (STSs) and to assess the correlations between these levels as well as their correlations with clinicopathological data and the disease-specific survival of STS patients. The mRNA levels of CCL2, CCL7 and CX3CL1 were analyzed in tumor tissues from 126 STS patients using qPCR. Low mRNA expression of CCL2 and CX3CL1 was significantly correlated with a worse prognosis (RR = 1.98; p = 0.019 and RR = 2.10; p = 0.014; multivariate Cox's regression analysis). A combined low expression of CCL2 and CX3CL1 was associated with a significantly increased risk of tumor-related death as compared to patients with high expression levels of both chemokines (RR = 3.08; p = 0.003). A gender-specific multivariate analysis revealed that female STS patients with low CX3CL1 mRNA expression had a 3.46-fold increased risk of death (p = 0.004). Low expression of both CCL2 and CX3CL1 mRNAs resulted in an additive 5.37-fold increased risk of tumor-related death (p = 0.003) as compared to those with high expression of both parameters in female patients. In conclusion, this is the first study to show a significant correlation between combined low expression of CCL2 and CX3CL1 and a poor prognosis for STS patients, particularly in female patients.

TREM1+ tumor-associated macrophages secrete CCL7 to promote hepatocellular carcinoma metastasis.

PURPOSE: Tumor-associated macrophages (TAMs) play a critical role in hepatocellular carcinoma (HCC) progression and metastasis. Systematic investigation of the cross-talk between TAMs and HCC may help in searching for the critical target to guard against HCC metastasis. METHODS AND RESULTS: Herein, we found that TREM1 highly expressed in HCC tissue by analyzing the data obtain from GEO database. Interestingly, the results indicated that TREM1 was primarily expressed by monocytes. Immune infiltration studies further validated that TREM1 expression was positively related with increased infiltration of macrophages in HCC tissues. In vitro, we observed that TREM1 knockdown significantly abrogated the effect of TAMs in promoting the metastasis and epithelial-mesenchymal transition (EMT) of HCC cells. Additionally, cytokine array detection identified CCL7 as the main responsive cytokine following with TREM1 knockdown in TAMs. CONCLUSION: Taken together, our findings strongly suggested that high expression of TREM1 was positively associated with metastasis and poor prognosis of HCC. Furthermore, TAMs expressing TREM1 contribute to EMT-based metastasis through secreting CCL7. These results provide a novel insight into the potential development of targeting the TREM1/CCL7 pathway for preventing metastatic HCC.

Low shear stress induces macrophage infiltration and aggravates aneurysm wall inflammation via CCL7/CCR1/TAK1/ NF-κB axis.

BACKGROUND: This study aimed to elucidate the mechanism by which wall shear stress (WSS) influences vascular walls, accounting for the susceptibility of intracranial aneurysms (IAs) to rupture. METHOD: We collected blood samples from the sacs of 24 ruptured and 28 unruptured IAs and analyzed the expression of chemokine CCL7 using enzyme-linked immunosorbent assay (ELISA). Univariate and multivariate logistic regression analyses were employed to assess clinical data, aneurysm morphology, and hemodynamics in both groups. Pearson correlation analysis investigated the relationship between CCL7 expression in aneurysm sac blood and WSS. Additionally, we established a bionic cell parallel plate co-culture shear stress model and a mouse low shear stress (LSS) model. The model was modulated using CCL7 recombinant protein, CCR1 inhibitor, and TAK1 inhibitor. We further evaluated CCL7 expression in endothelial cells and the levels of TAK1, NF-κB, IL-1ß, and TNF-α in macrophages. Subsequently, the intergroup differences in expression were calculated. RESULTS: CCL7 expression was significantly higher in the ruptured group compared to the unruptured group. Hemodynamic analysis indicated that WSS was an independent predictor of the risk of aneurysm rupture. A negative linear correlation was observed between CCL7 expression and WSS. Upon addition of CCL7 recombinant protein, upregulation of CCR1 expression and increased levels of p-TAK1 and p-p65 were observed. Treatment with CCR1 and TAK1 inhibitors reduced inflammatory cytokine expression in macrophages under LSS conditions. Overexpression of TAK1 significantly alleviated the inhibitory effects of CCR1 inhibitors on p-p65 and inflammatory cytokines. CONCLUSION: LSS prompts endothelial cells to secrete CCL7, which, upon binding to the macrophage surface receptor CCR1, stimulates the release of macrophage inflammatory factors via the TAK1/NF-κB signaling pathway. This process exacerbates aneurysm wall inflammation and increases the risk of aneurysm rupture.

Arrestin beta 1 Regulates Alveolar Progenitor Renewal and Lung Fibrosis.

The molecular mechanisms that regulate progressive pulmonary fibrosis remain poorly understood. Type 2 alveolar epithelial cells (AEC2s) function as adult stem cells in the lung. We previously showed that there is a loss of AEC2s and a failure of AEC2 renewal in the lungs of idiopathic pulmonary fibrosis (IPF) patients. We also reported that beta-arrestins are the key regulators of fibroblast invasion, and beta-arrestin 1 and 2 deficient mice exhibit decreased mortality, decreased matrix deposition, and increased lung function in bleomycin-induced lung fibrosis. However, the role of beta-arrestins in AEC2 regeneration is unclear. In this study, we investigated the role and mechanism of Arrestin beta 1 (ARRB1) in AEC2 renewal and in lung fibrosis. We used conventional deletion as well as cell type-specific deletion of ARRB1 in mice and found that Arrb1 deficiency in fibroblasts protects mice from lung fibrosis, and the knockout mice exhibit enhanced AEC2 regeneration in vivo, suggesting a role of fibroblast-derived ARRB1 in AEC2 renewal. We further found that Arrb1-deficient fibroblasts promotes AEC2 renewal in 3D organoid assays. Mechanistically, we found that CCL7 is among the top downregulated cytokines in Arrb1 deficient fibroblasts and CCL7 inhibits AEC2 regeneration in 3D organoid experiments. Therefore, fibroblast ARRB1 mediates AEC2 renewal, possibly by releasing chemokine CCL7, leading to fibrosis in the lung.

Comparing machine learning screening approaches using clinical data and cytokine profiles for COVID-19 in resource-limited and resource-abundant settings.

Accurate screening of COVID-19 infection status for symptomatic patients is a critical public health task. Although molecular and antigen tests now exist for COVID-19, in resource-limited settings, screening tests are often not available. Furthermore, during the early stages of the pandemic tests were not available in any capacity. We utilized an automated machine learning (ML) approach to train and evaluate thousands of models on a clinical dataset consisting of commonly available clinical and laboratory data, along with cytokine profiles for patients (n = 150). These models were then further tested for generalizability on an out-of-sample secondary dataset (n = 120). We were able to develop a ML model for rapid and reliable screening of patients as COVID-19 positive or negative using three approaches: commonly available clinical and laboratory data, a cytokine profile, and a combination of the common data and cytokine profile. Of the tens of thousands of models automatically tested for the three approaches, all three approaches demonstrated > 92% sensitivity and > 88 specificity while our highest performing model achieved 95.6% sensitivity and 98.1% specificity. These models represent a potential effective deployable solution for COVID-19 status classification for symptomatic patients in resource-limited settings and provide proof-of-concept for rapid development of screening tools for novel emerging infectious diseases.

Pilot study: elevated circulating levels of the proinflammatory cytokine macrophage migration inhibitory factor in patients with chronic spinal cord injury.

OBJECTIVE: To test the hypothesis that the proinflammatory cytokine macrophage migration inhibitory factor (MIF) is elevated in the circulation of patients with chronic spinal cord injury (SCI) relative to uninjured subjects, and secondarily to identify additional immune mediators that are elevated in subjects with chronic SCI. DESIGN: Prospective, observational pilot study. SETTING: Outpatient clinic of a department of physical medicine and rehabilitation and research institute in an academic medical center. PARTICIPANTS: Individuals with chronic (>1y from initial injury) SCI (n=22) and age- and sex-matched uninjured subjects (n=19). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Plasma levels of MIF, as determined by a commercially available multiplex suspension immunoassay. The relationship between MIF levels and clinical/demographic variables was also examined. As a secondary outcome, we evaluated other cytokines, chemokines, and growth factors. RESULTS: Plasma MIF levels were significantly higher in subjects with chronic SCI than in control subjects (P<.001). Elevated MIF levels were not correlated significantly with any one clinical or demographic characteristic. Subjects with SCI also exhibited significantly higher plasma levels of monokine induced by interferon-gamma/chemokine C-X-C motif ligand 9 (P<.03), macrophage colony stimulating factor (P<.035), interleukin-3 (P<.044), and stem cell growth factor beta (SCGF-ß) (P<.016). Among subjects with SCI, the levels of SCGF-ß increased with the time from initial injury. CONCLUSIONS: These data confirm the hypothesis that MIF is elevated in subjects with chronic SCI and identify additional novel immune mediators that are also elevated in these subjects. This study suggests the importance of examining the potential functional roles of MIF and other immune factors in subjects with chronic SCI.

Serum CCL7 Is a Novel Prognostic Biomarker of Metastatic Colorectal Cancer.

BACKGROUND/AIM: Colorectal cancer is the third most common cancer globally, and the poor prognosis of patients with metastatic colorectal cancer (mCRC) warrants urgent attention. We previously obtained 10 candidate serum biomarkers for mCRC. Our aim with this study was to determine the prognostic performance of the pre-treatment serum C-C motif chemokine ligand 7 (CCL7) concentration in patients with mCRC. PATIENTS AND METHODS: Protein concentrations of CCL7 were examined using ELISA and immunohistochemistry for serum (n=110) and surgical specimens (n=85), respectively, of patients with mCRC. The relationship between protein concentration and prognosis was examined using Cox regression analysis, receiver operator characteristic curve analysis and the Kaplan-Meier method. RESULTS: The overall survival (OS) of patients with high concentrations of serum CCL7 was significantly poorer than that of patients with low concentrations. Patients with a high CCL7 concentration in the stroma had significantly poorer outcomes than those with a low concentration. The concentrations of carcinoembryonic antigen (CEA) and carbohydrate antigen 19-9 were significantly higher in the high-CCL7 group, compared to those in the low-CCL7 group. Univariate and multivariate analysis revealed that serum CCL7 concentration was a significant prognostic factor for mCRC. The combination of serum CCL and CEA concentrations was also useful in this regard (area under the curve=0.71). CONCLUSION: The combined pre-treatment serum levels of CCL7 and CEA are useful prognostic biomarkers for mCRC.