Overexpression of SPACIA1/SAAL1, a newly identified gene that is involved in synoviocyte proliferation, accelerates the progression of synovitis in mice and humans

CDK6-Dependent, CDK4-Independent Synovial Hyperplasia in Arthritic Mice and Tumor Necrosis Factor-α-Induced Proliferation of Synovial Fibroblasts

Palbociclib, a dual CDK4/6 kinase inhibitor used for breast cancer, has been explored as a treatment option for rheumatoid arthritis (RA). Preclinical studies have reported palbociclib-induced myelosuppression, but no such effects have been observed in Cdk4 or Cdk6 single-deficient mice. Synoviocyte proliferation-associated in collagen-induced arthritis 1/serum amyloid A-like 1 (SPACIA1/SAAL1) is involved in G1 phase progression. Given that SPACIA1/SAAL1 upregulates CDK6 (but not CDK4) expression, we aimed to determine whether suppressing CDK6 expression alone could prevent synovial hyperplasia without myelosuppression. The effects of CDK6 expression on TNF-α-induced rheumatoid arthritis synovial fibroblast (RASF) proliferation and synovial hyperplasia in collagen-induced arthritis (CIA) mice were investigated by modulating the transcriptional level with a CDK6 expression inhibitor (indole-3-carbinol), CDK6 small interfering RNA (siRNA), and Cdk6-deficient mice. Indole-3-carbinol or CDK6 siRNA inhibited TNF-α-induced RASF proliferation without suppressing CDK4 expression and reduced retinoblastoma protein phosphorylation. In CIA mice, indole-3-carbinol did not cause myelosuppression, considerably delayed CIA onset and progression, and reduced arthritis severity. Cdk6-deficient mice showed similar improvements in CIA pathogenesis but had lower serum anti-type II collagen IgG levels. Notably, synovial hyperplasia was not observed in Cdk6-deficient mice. CIA-synovial hyperplasia depends on CDK6, but not CDK4, expression.

The effects of the prognostic biomarker SAAL1 on cancer growth and its association with the immune microenvironment in lung adenocarcinoma

BACKGROUND

Inhibition of Serum Amyloid A-like 1 (SAAL1) expression could inhibit cancer progression and improve the prognosis of cancer patients. At present, the correlation between SAAL1 and lung adenocarcinoma (LAC) remains unclear. Therefore, this study surveyed the worth and pathway of SAAL1 in LAC progression and immunity.

METHODS

Bioinformatics and immunohistochemistry were used to identify the SAAL1 expression in LAC. The roles of SAAL1 expression in the existence values of LAC patients were explored, and the nomograms were constructed. Clinical values of SAAL1 co-expressed genes were evaluated by COX regression, survival, and Receiver operating characteristic (ROC) analysis. EDU and western blotting methods were used to inquiry the functions and pathways of the SAAL1 in cell growths. The correlation between the SAAL1 level and immune microenvironment was visualized using correlation research.

RESULTS

SAAL1 level was elevated in LAC tissues, and was observed in cancer tissues of dead patients. SAAL1 overexpression had something to do with shorter overall survival, progression-free interval, and disease-specific survival in LAC. The area under the curve of SAAL1 was 0.902 in normal tissues and cancer tissues. Inhibition of SAAL1 expression could inhibit cancer cell proliferation, which may be related to the decreased expression of cyclin D1 and Bcl-2 proteins. In LAC, SAAL1 level had something to do with stromal, immune, and estimate scores, and correlated with macrophages, T cells, Th2 cells, CD8 T cells, NK CD56dim cells, DC, eosinophils, NK CD56bright cells, pDC, iDC, cytotoxic cells, Tgd, aDC cells, B cells, Tcm, and TFH levels. SAAL1 overexpression had something to do with existence values and the immunity in LAC.

CONCLUSIONS

Inhibition of SAAL1 expression could regulate cancer growth via cyclin D1 and Bcl-2. SAAL1 is a promising prognostic biomarker in LAC patients.

Transcriptomic profiles of the ruminal wall in Italian Mediterranean dairy buffaloes fed green forage

BACKGROUND

Green feed diet in ruminants exerts a beneficial effect on rumen metabolism and enhances the content of milk nutraceutical quality. At present, a comprehensive analysis focused on the identification of genes, and therefore, biological processes modulated by the green feed in buffalo rumen has never been reported. We performed RNA-sequencing in the rumen of buffaloes fed a total mixed ration (TMR) + the inclusion of 30% of ryegrass green feed (treated) or TMR (control), and identified differentially expressed genes (DEGs) using EdgeR and NOISeq tools.

RESULTS

We found 155 DEGs using EdgeR (p-values < 0.05) and 61 DEGs using NOISeq (prob ≥0.8), 30 of which are shared. The rt-qPCR validation suggested a higher reliability of EdgeR results as compared with NOISeq data, in our biological context. Gene Ontology analysis of DEGs identified using EdgeR revealed that green feed modulates biological processes relevant for the rumen physiology and, then, health and well-being of buffaloes, such as lipid metabolism, response to the oxidative stress, immune response, and muscle structure and function. Accordingly, we found: (i) up-regulation of HSD17B13, LOC102410803 (or PSAT1) and HYKK, and down-regulation of CDO1, SELENBP1 and PEMT, encoding factors involved in energy, lipid and amino acid metabolism; (ii) enhanced expression of SIM2 and TRIM14, whose products are implicated in the immune response and defense against infections, and reduced expression of LOC112585166 (or SAAL1), ROR2, SMOC2, and S100A11, encoding pro-inflammatory factors; (iii) up-regulation of NUDT18, DNAJA4 and HSF4, whose products counteract stressful conditions, and down-regulation of LOC102396388 (or UGT1A9) and LOC102413340 (or MRP4/ABCC4), encoding detoxifying factors; (iv) increased expression of KCNK10, CACNG4, and ATP2B4, encoding proteins modulating Ca²⁺ homeostasis, and reduced expression of the cytoskeleton-related MYH11 and DES.

CONCLUSION

Although statistically unpowered, this study suggests that green feed modulates the expression of genes involved in biological processes relevant for rumen functionality and physiology, and thus, for welfare and quality production in Italian Mediterranean dairy buffaloes. These findings, that need to be further confirmed through the validation of additional DEGs, allow to speculate a role of green feed in the production of nutraceutical molecules, whose levels might be enhanced also in milk.

SAAL1, a novel oncogene, is associated with prognosis and immunotherapy in multiple types of cancer

Serum amyloid A-like 1 (SAAL1) was recently identified as a novel oncogene in hepatocellular carcinoma (HCC). To explore the potential role of SAAL1 in other cancers, we conducted a pan-cancer analysis of SAAL1 expression and its association with tumor microenvironment (TME) immunological profiles, sensitivity to chemotherapy agents, response to immunotherapy, and patient prognosis. SAAL1 was overexpressed in most malignant tumors in association with poor prognosis. Moreover, its expression was positively correlated with TME-relevant immune and mismatch signatures, immunostimulatory infiltrating cells (CD4⁺ memory T cells, activated NK cells, M1 macrophages, and cytotoxic CD8⁺ T cells), microsatellite instability (MSI), tumor mutational burden (TMB), neoantigen load, and immune checkpoint markers (PD-L1, LAG-3 and CTLA-4) in multiple cancers. SAAL1 overexpression was also associated with immunotherapy response and overall survival (OS) in bladder cancer (BLCA) patients who had received anti-PD-L1 treatment. Gene set enrichment analysis (GSEA) further showed significant enrichment of SAAL1 in immune cell signaling, cell cycle, and cell adhesion pathways. Moreover, we detected tumor-specific correlations between SAAL1 expression and either chemoresistance or sensitivity to common chemotherapeutics. Lastly, we showed that SAAL1 silencing suppresses both malignant phenotype and expression of PD-L1 in lung cancer A549 cells in vitro. These findings suggest that SAAL1 contributes to tumorigenesis and antitumor immunity mechanisms in different cancer types, and may thus serve as both a prognostic biomarker and potential target for cancer immunotherapy.

Mycoplasma synoviae induces serum amyloid A upregulation and promotes chicken synovial fibroblast cell proliferation

Mycoplasma synoviae (MS) infection causes infectious synovitis and arthritis with hyperplasia of synovial cells in the chicken joint. However, its mechanism is unknown. We used primary chicken synovial fibroblast (CSF) as the research object to study the role of MS in the proliferation of MS-infected CSF and determine the mechanisms involved. Using integrated transcriptomic and proteomic analyses of the interaction between CSF and MS, we screened a proliferation-regulated factor, serum amyloid A (SAA), that may regulate proliferation of MS-infected CSF. SAA appears to be associated with MS-induced CSF proliferation. To study the role of SAA in MS-induced CSF proliferation, a eukaryotic expression vector overexpressing SAA and a small interfering RNA (siRNA) targeting Saa were constructed to manipulate the expression of SAA. Cell proliferation and apoptosis were detected via cell counting kit-8 (CCK-8), 5-Ethynyl-2'-deoxyuridine (EdU), or terminal deoxyribonucleotidyl transferase-mediated dUTP nick-dnd labeling (TUNEL) assays, respectively. Western blot analysis was used to examine the protein expression level of SAA, cyclin E1, and cyclin-dependent kinase 2 (CDK2). In vitro, MS significantly promoted the proliferation of CSF and increased the production of SAA. Overexpression of SAA accelerated the proliferative ability of CSF, whereas knockdown of SAA depressed the proliferative ability of CSF. A TUNEL assay indicated that MS did not induce apoptosis. Silencing of SAA suppressed the expression of cyclin E1 and CDK2. These results suggest that MS may upregulate the expression of SAA, accelerate the cell cycle, and promote proliferation of CSF.

Identification of the Novel Oncogenic Role of SAAL1 and Its Therapeutic Potential in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is the third leading cause of cancer deaths worldwide, affecting over 700,000 people per year. The treatment effect in advanced HCC is still disappointing and prognosis of advanced HCC remains poor. Hence, to find more effective therapeutic targets to improve the treatment outcome of HCC is of urgent need. In this study, we reported the novel oncogenic function of SAAL1 (serum amyloid A-like 1) in HCC, which previously is considered as an inflammation-related gene. We found that SAAL1 was significantly upregulated in HCC tumor tissues when compared to the adjacent normal tissues and high expression of SAAL1 correlated with shorter overall survival in The Cancer Genome Atlas (TCGA) HCC database. Functionally, we showed that the depletion of SAAL1 significantly reduced cell proliferation, 3D colony formation, and migration/invasion abilities of HCC cancer cells. Furthermore, suppression of SAAL1 impaired the HGF/Met-driven Akt/mTOR phosphorylation cascade and increased the chemosensitivity of HCC cells to sorafenib and foretinib treatment. Our data indicated that SAAL1 plays an important role in HCC via mediating oncogenic HGF/Met-driven Akt/mTOR signaling and could serve as an independent prognostic marker, as well as a promising therapeutic target for HCC patients.

SPACIA1/SAAL1 Deletion Results in a Moderate Delay in Collagen-Induced Arthritis Activity, along with mRNA Decay of Cyclin-dependent Kinase 6 Gene

This study was performed to elucidate the molecular function of the synoviocyte proliferation-associated in collagen-induced arthritis (CIA) 1/serum amyloid A-like 1 (SPACIA1/SAAL1) in mice CIA, an animal model of rheumatoid arthritis (RA), and human RA-synovial fibroblasts (RASFs). SPACIA1/SAAL1-deficient mice were generated and used to create mouse models of CIA in mild or severe disease conditions. Cell cycle-related genes, whose expression levels were affected by SPACIA1/SAAL1 small interfering RNA (siRNA), were screened. Transcriptional and post-transcriptional effects of SPACIA1/SAAL1 siRNA on cyclin-dependent kinase (cdk) 6 gene expression were investigated in human RASFs. SPACIA1/SAAL1-deficient mice showed later onset and slower progression of CIA than wild-type mice in severe disease conditions, but not in mild conditions. Expression levels of cdk6, but not cdk4, which are D-type cyclin partners, were downregulated by SPACIA1/SAAL1 siRNA at the post-transcriptional level. The exacerbation of CIA depends on SPACIA1/SAAL1 expression, although CIA also progresses slowly in the absence of SPACIA1/SAAL1. The CDK6, expression of which is up-regulated by the SPACIA1/SAAL1 expression, might be a critical factor in the exacerbation of CIA.

Complement Factor H and Apolipoprotein E Participate in Regulation of Inflammation in THP-1 Macrophages

The alternative pathway (AP) of complement is constantly active in plasma and can easily be activated on self surfaces and trigger local inflammation. Host cells are protected from AP attack by Factor H (FH), the main AP regulator in plasma. Although complement is known to play a role in atherosclerosis, the mechanisms of its contribution are not fully understood. Since FH via its domains 5-7 binds apoliporotein E (apoE) and macrophages produce apoE we examined how FH could be involved in the antiatherogenic effects of apoE. We used blood peripheral monocytes and THP-1 monocyte/macrophage cells which were also loaded with acetylated low-density lipoprotein (LDL) to form foam cells. Binding of FH and apoE on these cells was analyzed by flow cytometry. High-density lipoprotein (HDL)-mediated cholesterol efflux of activated THP-1 cells was measured and transcriptomes of THP-1 cells using mRNA sequencing were determined. We found that binding of FH to human blood monocytes and cholesterol-loaded THP-1 macrophages increased apoE binding to these cells. Preincubation of fluorescent cholesterol labeled THP-1 macrophages in the presence of FH increased cholesterol efflux and cholesterol-loaded macrophages displayed reduced transcription of proinflammatory/proatherogenic factors and increased transcription of anti-inflammatory/anti-atherogenic factors. Further incubation of THP-1 cells with serum reduced C3b/iC3b deposition. Overall, our data indicate that apoE and FH interact with monocytic cells in a concerted action and this interaction reduces complement activation and inflammation in the atherosclerotic lesions. By this way FH may participate in mediating the beneficial effects of apoE in suppressing atherosclerotic lesion progression.

Caucasian Families Exhibit Significant Linkage of Myopia to Chromosome 11p

Purpose

Myopia is a common visual disorder caused by eye overgrowth, resulting in blurry vision. It affects one in four Americans, and its prevalence is increasing. The genetic mechanisms that underpin myopia are not completely understood. Here, we use genotype data and linkage analyses to identify high-risk genetic loci that are significantly linked to myopia.

Methods

Individuals from 56 Caucasian families with a history of myopia were genotyped on an exome-based array, and the single nucleotide polymorphism (SNP) data were merged with microsatellite genotype data. Refractive error measures on the samples were converted into binary phenotypes consisting of affected, unaffected, or unknown myopia status. Parametric linkage analyses assuming an autosomal dominant model with 90% penetrance and 10% phenocopy rate were performed.

Results

Single variant two-point analyses yielded three significantly linked SNPs at 11p14.1 and 11p11.2; a further 45 SNPs at 11p were found to be suggestive. No other chromosome had any significant SNPs or more than seven suggestive linkages. Two of the significant SNPs were located in BBOX1-AS1 and one in the intergenic region between ORA47 and TRIM49B. Collapsed haplotype pattern two-point analysis and multipoint analyses also yielded multiple suggestively linked genes at 11p. Multipoint analysis also identified suggestive evidence of linkage on 20q13.

Conclusions

We identified three genome-wide significant linked variants on 11p for myopia in Caucasians. Although the novel specific signals still need to be replicated, 11p is a promising region that has been identified by other linkage studies with a number of potentially interesting candidate genes. We hope that the identification of these regions on 11p as potential causal regions for myopia will lead to more focus on these regions and maybe possible replication of our specific linkage peaks in other studies. We further plan targeted sequencing on 11p for our most highly linked families to more clearly understand the source of the linkage in this region.

Muscle wasting associated with pathologic change is a risk factor for the exacerbation of joint swelling in collagen-induced arthritis in cynomolgus monkeys

BACKGROUND

Not only joint destruction but also muscle wasting due to rheumatoid cachexia has been problem in terms of quality of life of patients with rheumatoid arthritis (RA). In the present study, we performed histopathological examination and assessed relationships between characteristic parameters relating to muscle and joint swelling in a collagen-induced arthritis (CIA) model using cynomolgus monkeys (CMs).

METHODS

Female CMs were used and CIA was induced by twice immunizations using bovine type II collagen with Freund's complete adjuvant. Arthritis level was evaluated from the degree of swelling at the peripheral joints of the fore and hind limbs. Food consumption, body weight, and serum biochemical parameters were measured sequentially. Five or 6 animals per time point were sacrificed at 2, 3, 5 and 9 weeks after the first immunization to obtain quadriceps femoris specimens for histopathology. Pimonidazole hydrochloride was intravenously administered to determine tissue hypoxia in skeletal muscle.

RESULTS

Gradual joint swelling was observed and the maximum arthritis score was noted at Week 5. In histopathology, necrosis of muscle fiber in the quadriceps femoris was observed only at Week 2 and the most significant findings such as degeneration, atrophy, and regeneration of muscle fiber were mainly observed at Week 5. Food consumption was decreased up to Week 4 but recovered thereafter. Body weight decreased up to Week 5 and did not completely recover thereafter. A biphasic increase in serum cortisol was also observed at Weeks 2 and 5. Histopathology showed that muscle lesions were mainly composed of degeneration and atrophy of the muscle fibers, and ATPase staining revealed that the changes were more pronounced in type II muscle fiber than type I muscle fiber. In the pimonidazole experiment, mosaic pattern in skeletal muscle was demonstrated in the intact animal, but not the CIA animal. Increased arthritis score was accompanied by a decrease in serum creatinine, a marker that reflects muscle mass.

CONCLUSIONS

Muscle wasting might exacerbate joint swelling in a collagen-induced arthritis model of cynomolgus monkeys.

A novel acute phase reactant, serum amyloid A-like 1, from Oplegnathus fasciatus: genomic and molecular characterization and transcriptional expression analysis

Acute phase response is a significant component of innate immunity, playing a vital role in the signaling processes and elimination of invading pathogens. Acute phase proteins are synthesized in liver and secreted into the blood for transportation to an infection site, where the defense function is exerted. Serum amyloid A (SAA) and C-reactive proteins are the major positive acute phase proteins. In this study, we have identified and characterized a novel SAA related gene from rock bream (Oplegnathus fasciatus), designated OfSAAL1. Genomic characterization revealed the presence of 13 exons and 12 introns, similar to SAAL1 in zebrafish. Multiple protein sequence alignment revealed high conservation with other SAAL1 homologues. Phylogenetic analysis showed that OfSAAL1 clustered with another fish homologue, and pairwise alignment revealed highest identity and similarity at the amino acid level with zebrafish SAAL1. Promoter region analysis revealed the presence of immunologically significant transcription factor binding sites. Tissue distribution profiling to indicate physiological relevance showed the highest levels occur in blood, followed by liver, suggesting a positive immune role in rock bream. Transcriptional analysis by reverse transcription polymerase chain reaction to understand OfSAAL1 responsiveness to immune challenge with poly I:C, Edwardsiella tarda, Streptococcus iniae and rock bream iridovirus, revealed a significant level of elevation from 12h to 48 h post-infection in blood, spleen, head kidney, and liver. To our knowledge, OfSAAL1 is the first characterized SAAL1 homologue from teleosts. We anticipate that its identification will prove inspiring for further studies of SAAL1 homologues as biomarkers of the acute phase response.