Discovery of non-genomic drivers of YAP signaling modulating the cell plasticity in CRC tumor lines

In normal intestines, a fetal/regenerative/revival cell state can be induced upon inflammation. This plasticity in cell fate is also one of the current topics in human colorectal cancer (CRC). To dissect the underlying mechanisms, we generated human CRC organoids with naturally selected genetic mutation profiles and exposed them to two different conditions by modulating the extracellular matrix (ECM). Among tested mutation profiles, a fetal/regenerative/revival state was induced following YAP activation via a collagen type I-enriched microenvironment. Mechanistically, YAP transcription was promoted by activating AP-1 and TEAD-dependent transcription and suppressing intestinal lineage-determining transcription via mechanotransduction. The phenotypic conversion was also involved in chemoresistance, which could be potentially resolved by targeting the underlying YAP regulatory elements, a potential target of CRC treatment.

Concordance between IDEXX Legiolert® (liquid culture assay) and plate culture (ISO 11731:2017) for the detection and quantification of Legionella pneumophila in water samples

BACKGROUND

Legionella pneumophila is a water-borne bacterium that can cause Legionnaires' disease. Legiolert® (IDEXX, USA) is a low-labour liquid culture assay for the detection and enumeration of L. pneumophila (SG1-15) from water.

AIM

To analyse concordance between Legiolert and ISO 11731:2017 plate culture method (membrane filtration and culture on selective agars) using hospital water samples (N = 100).

METHODS

Incubation was at 39 °C and 36 °C, respectively, for seven days, followed by most-probable enumeration for Legiolert and subculturing and serogrouping of suspected Legionella colonies, with plate culture.

FINDINGS

L. pneumophila (SG1-15) was isolated from 25 out of 100 samples when using Legiolert or plate culture. Fourteen additional Legiolert samples tested positive for L. pneumophila; analysis of the same samples by plate culture was negative (12 out of 14) or yielded only Legionella rubrilucens (two out of 14; confirmed via matrix-assisted ionization/desorption time-of-flight mass spectrometry). L. pneumophila was not captured from Quanti-Tray/Legiolert pouch wells of these positive samples after subculture of puncture aliquots on buffered charcoal yeast-extract agar. Both methods in concordance did not detect L. pneumophila in 61 out of 100 samples.

CONCLUSION

Legiolert and plate culture are both satisfactory methods to detect L. pneumophila from water samples, and both to detect isolated L. pneumophila in 25% of the sample population. Legiolert provides a faster time to result, and is less resource-demanding and labour-intensive; however, there may be a low risk of cross-reactivity with other organisms. Both methods are suitable for the analysis of water in healthcare settings, where the monitoring of L. pneumophila is imperative in preventing cases of Legionnaires' disease.

The Effect of Vitamin D3 and Valproic Acid on the Maturation of Human-Induced Pluripotent Stem Cell-Derived Enterocyte-Like Cells

Cytochrome P450 3A4 (CYP3A4) is involved in first-pass metabolism in the small intestine and is heavily implicated in oral drug bioavailability and pharmacokinetics. We previously reported that vitamin D3 (VD3), a known CYP enzyme inducer, induces functional maturation of iPSC-derived enterocyte-like cells (iPSC-ent). Here, we identified a Notch activator and CYP modulator valproic acid (VPA), as a promotor for the maturation of iPSC-ent. We performed bulk RNA sequencing to investigate the changes in gene expression during the differentiation and maturation periods of these cells. VPA potentiated gene expression of key enterocyte markers ALPI, FABP2, and transporters such as SULT1B1. RNA-sequencing analysis further elucidated several function-related pathways involved in fatty acid metabolism, significantly upregulated by VPA when combined with VD3. Particularly, VPA treatment in tandem with VD3 significantly upregulated key regulators of enterohepatic circulation, such as FGF19, apical bile acid transporter SLCO1A2 and basolateral bile acid transporters SLC51A and SLC51B. To sum up, we could ascertain the genetic profile of our iPSC-ent cells to be specialized toward fatty acid absorption and metabolism instead of transporting other nutrients, such as amino acids, with the addition of VD3 and VPA in tandem. Together, these results suggest the possible application of VPA-treated iPSC-ent for modelling enterohepatic circulation.

Collagen type I-mediated mechanotransduction controls epithelial cell fate conversion during intestinal inflammation

BACKGROUND

The emerging concepts of fetal-like reprogramming following tissue injury have been well recognized as an important cue for resolving regenerative mechanisms of intestinal epithelium during inflammation. We previously revealed that the remodeling of mesenchyme with collagen fibril induces YAP/TAZ-dependent fate conversion of intestinal/colonic epithelial cells covering the wound bed towards fetal-like progenitors. To fully elucidate the mechanisms underlying the link between extracellular matrix (ECM) remodeling of mesenchyme and fetal-like reprogramming of epithelial cells, it is critical to understand how collagen type I influence the phenotype of epithelial cells. In this study, we utilize collagen sphere, which is the epithelial organoids cultured in purified collagen type I, to understand the mechanisms of the inflammatory associated reprogramming. Resolving the entire landscape of regulatory networks of the collagen sphere is useful to dissect the reprogrammed signature of the intestinal epithelium.

METHODS

We performed microarray, RNA-seq, and ATAC-seq analyses of the murine collagen sphere in comparison with Matrigel organoid and fetal enterosphere (FEnS). We subsequently cultured human colon epithelium in collagen type I and performed RNA-seq analysis. The enriched genes were validated by gene expression comparison between published gene sets and immunofluorescence in pathological specimens of ulcerative colitis (UC).

RESULTS

The murine collagen sphere was confirmed to have inflammatory and regenerative signatures from RNA-seq analysis. ATAC-seq analysis confirmed that the YAP/TAZ-TEAD axis plays a central role in the induction of the distinctive signature. Among them, TAZ has implied its relevant role in the process of reprogramming and the ATAC-based motif analysis demonstrated not only Tead proteins, but also Fra1 and Runx2, which are highly enriched in the collagen sphere. Additionally, the human collagen sphere also showed a highly significant enrichment of both inflammatory and fetal-like signatures. Immunofluorescence staining confirmed that the representative genes in the human collagen sphere were highly expressed in the inflammatory region of ulcerative colitis.

CONCLUSIONS

Collagen type I showed a significant influence in the acquisition of the reprogrammed inflammatory signature in both mice and humans. Dissection of the cell fate conversion and its mechanisms shown in this study can enhance our understanding of how the epithelial signature of inflammation is influenced by the ECM niche.

Transplantation of intestinal organoids into a mouse model of colitis

Intestinal organoids are fundamental in vitro tools that have enabled new research opportunities in intestinal stem cell research. Organoids can also be transplanted in vivo, which enables them to probe stem cell potential and be used for disease modeling and as a preclinical tool in regenerative medicine. Here we describe in detail how to orthotopically transplant epithelial organoids into the colon of recipient mice. In this assay, epithelial injury is initiated at the distal part of colon by the administration of dextran sulfate sodium, and organoids are infused into the luminal space via the anus. The infused organoids subsequently attach to the injured region and rebuild a donor-derived epithelium. The steps for cell infusion can be completed in 10 min. The assay has been applied successfully to organoids derived from both wild-type and genetically altered epithelial cells from adult colonic and small intestinal epithelium, as well as fetal small intestine. This is a versatile protocol, providing the technical basis for transplantation following alternative colonic injury models. It has been used previously for functional assays to probe cellular potential, and formed the basis for the first in-human clinical trial using colonic organoid transplantation therapy for intractable cases of ulcerative colitis.

Thermal disinfection at suboptimal temperature of Pseudomonas aeruginosa biofilm on copper pipe and shower hose materials

BACKGROUND

Hospital-acquired infections caused by Pseudomonas aeruginosa have been linked to contaminated shower systems in health care. Thermal disinfection, whereby colonized outlets are flushed with existing hot water supplies, is a commonly used method to disinfect contaminated systems. Temperatures of 60°C are recommended for inactivation of P. aeruginosa; however, this is often not achievable at outlets.

AIM

To investigate whether thermal disinfection at a suboptimal temperature (58°C) can effectively eradicate planktonic P. aeruginosa and biofilm adherent on copper piping and shower hoses. Exposure times of up to 60 min and efficacy of repeated cycles were evaluated.

METHODS

A type culture and an environmental strain of P. aeruginosa isolated from a hospital shower were tested. Planktonic bacteria and biofilm adhered to sections of copper pipe and shower hoses were exposed to water at 58°C for up to 60 min. Biofilms were tested with static water, flushing water and repeated cycles of disinfection. Remaining viable bacteria after disinfection were enumerated.

FINDINGS

Planktonic P. aeruginosa remained viable after up to 60 min of thermal disinfection. With static water, biofilm was removed from copper piping after 15 min, but remained viable in shower hoses for up to 60 min. With thermal flushing, biofilm was fully eradicated from copper piping after 2 min, but remained viable on shower hoses. Repeated cycles did not shorten thermal disinfection exposure times.

CONCLUSION

Thermal disinfection at 58°C was effective at eliminating biofilm on copper; however, biofilm on shower hoses remained viable after 60 min of exposure.

Notch and TNF-α signaling promote cytoplasmic accumulation of OLFM4 in intestinal epithelium cells and exhibit a cell protective role in the inflamed mucosa of IBD patients

Notch signaling is activated in the intestinal epithelial cells (IECs) of patients with inflammatory bowel disease (IBD), and contributes to mucosal regeneration. Our previous study indicated that TNF-α and Notch signaling may synergistically promote the expression of the intestinal stem cell (ISC) marker OLFM4 in human IECs. In the present study, we investigated the gene regulation and function of OLFM4 in human IEC lines. We confirmed that TNF-α and Notch synergistically upregulate the mRNA expression of OLFM4. Luciferase reporter assay showed that OLFM4 transcription is regulated by the synergy of TNF-α and Notch. At the protein level, synergy between TNF-α and Notch promoted cytoplasmic accumulation of OLFM4, which has potential anti-apoptotic properties in human IECs. Analysis of patient-derived tissues and organoids consistently showed cytoplasmic accumulation of OLFM4 in response to NF-κB and Notch activation. Cytoplasmic accumulation of OLFM4 in human IECs is tightly regulated by Notch and TNF-α in synergy. Such cytoplasmic accumulation of OLFM4 may have a cell-protective role in the inflamed mucosa of patients with IBD.

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Notch and TNF-α signaling is important in IECs of patients with IBD.

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Notch and TNF-α signaling promotes the cytoplasmic accumulation of OLFM4.

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OLFM4 accumulation may have anti-apoptotic properties.

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OLFM4 could protect against mucosal inflammation in IBD.

Functional analysis of isoflavones using patient-derived human colonic organoids

Inflammatory bowel disease (IBD) comprises two major subtypes, ulcerative colitis (UC) and Crohn's disease, which are multifactorial diseases that may develop due to genetic susceptibility, dysbiosis, or environmental factors. Environmental triggers of IBD include food-borne factors, and a previous nationwide survey in Japan identified pre-illness consumption of isoflavones as a risk factor for UC. However, the precise mechanisms involved in the detrimental effects of isoflavones on the intestinal mucosa remain unclear. The present study employed human colonic organoids (hCOs) to investigate the functional effect of two representative isoflavones, genistein and daidzein, on human colonic epithelial cells. The addition of genistein to organoid reformation assays significantly decreased the number and size of reformed hCOs compared with control and daidzein treatment, indicating an inhibitory effect of genistein on colonic cell/progenitor cell function. Evaluation of the phosphorylation status of 49 different receptor tyrosine kinases showed that genistein selectively inhibited phosphorylation of epidermal growth factor receptor (EGFR) and hepatocyte growth factor receptor (HGFR). We established a two-dimensional wound-repair model using hCOs and showed that genistein significantly delayed the overall wound-repair response. Our results collectively show that genistein may exert its detrimental effects on the intestinal mucosa via negative regulation of stem/progenitor cell function, possibly leading to sustained mucosal injury and the development of UC.

Organoid-based regenerative medicine for inflammatory bowel disease

Inflammatory bowel disease (IBD) consists of two major idiopathic gastrointestinal diseases: ulcerative colitis and Crohn's disease. Although a significant advance has been achieved in the treatment of IBD, there remains a particular population of patients that are refractory to the conventional treatments, including the biologic agents. Studies have revealed the importance of "mucosal healing" in improving the prognosis of those difficult-to-treat patients, which indicates the proper and complete regeneration of the damaged intestinal tissue. In this regard, organoid-based regenerative medicine may have the potential to dramatically promote the achievement of mucosal healing in refractory IBD patients, and thereby improve their long-term prognosis as well. So far, studies have shown that hematopoietic stem cells (HSCs) and mesenchymal stem cells (MSCs) may have some beneficial effect on IBD patients through their transplantation or transfusion. Recent advance in stem cell biology has added intestinal stem cells (ISCs) as a new player in this field. It has been shown that ISCs can be grown in vitro as organoids and that those ex-vivo cultured organoids can be employed as donor cells for transplantation studies. Further studies using mice colitis models have shown that ex-vivo cultured organoids can engraft onto the colitic ulcers and reconstruct the crypt-villus structures. Such transplantation of organoids may not only facilitate the regeneration of the refractory ulcers that may persist in IBD patients but may also reduce the risk of developing colitis-associated cancers. Endoscopy-assisted transplantation of organoids may, therefore, become one of the alternative therapies for refractory IBD patients.

Ubiquitin D is Upregulated by Synergy of Notch Signalling and TNF-α in the Inflamed Intestinal Epithelia of IBD Patients

BACKGROUND AND AIMS

The intestinal epithelium of inflammatory bowel disease [IBD] patients is exposed to various pro-inflammatory cytokines, most notably tumour necrosis factor alpha [TNF-α]. We have previously shown that the Notch signalling pathway is also upregulated in such an epithelium, contributing to intestinal epithelial cell [IEC] proliferation and regeneration. We aimed to reproduce such environment in vitro and explore the gene regulation involved.

METHODS

Human IEC cell lines or patient-derived organoids were used to analyse Notch- and TNF-α-dependent gene expression. Immunohistochemistry was performed to analyse expression of ubiquitin D [UBD] in various patient-derived intestinal tissues.

RESULTS

In human IEC cell lines, we found that Notch signalling and TNF-α-induced NFκB signalling are reciprocally regulated to promote expression of a specific gene subset. Global gene expression analysis identified UBD to be one of the most highly upregulated genes, due to synergy of Notch and TNF-α. The synergistic expression of UBD was regulated at the transcriptional level, whereas the UBD protein had an extremely short half-life due to post-translational, proteasomal degradation. In uninflamed intestinal tissues from IBD patients, UBD expression was limited to IECs residing at the crypt bottom. In contrast, UBD-expressing IECs were seen throughout the crypt in inflamed tissues, indicating substantial induction by the local inflammatory environment. Analysis using patient-derived organoids consistently confirmed conserved Notch- and TNF-α-dependent expression of UBD. Notably, post-infliximab [IFX] downregulation of UBD reflected favourable outcome in IBD patients.

CONCLUSION

We propose that UBD is a novel inflammatory-phase protein expressed in IECs, with a highly rapid responsiveness to anti-TNF-α treatment.

Ultraviolet-C decontamination of hand-held tablet devices in the healthcare environment using the Codonics D6000™ disinfection system

Mobile phones and tablet computers may be contaminated with micro-organisms and become a potential reservoir for cross-transmission of pathogens between healthcare workers and patients. There is no generally accepted guidance on how to reduce contamination on mobile devices in healthcare settings. Our aim was to determine the efficacy of the Codonics D6000™ UV-C disinfection device. Daily disinfection reduced contamination on screens and on protective cases (test) significantly, but not all cases (control) could be decontaminated. The median aerobic colony count on the control and the test cases was 52 cfu/25 cm² (interquartile range: 33-89) and 22 cfu/25 cm² (10.5-41), respectively, before disinfection.

Single cell analysis of Crohn's disease patient-derived small intestinal organoids reveals disease activity-dependent modification of stem cell properties

BACKGROUND

Intestinal stem cells (ISCs) play indispensable roles in the maintenance of homeostasis, and also in the regeneration of the damaged intestinal epithelia. However, whether the inflammatory environment of Crohn's disease (CD) affects properties of resident small intestinal stem cells remain uncertain.

METHODS

CD patient-derived small intestinal organoids were established from enteroscopic biopsy specimens taken from active lesions (aCD-SIO), or from mucosa under remission (rCD-SIO). Expression of ISC-marker genes in those organoids was examined by immunohistochemistry, and also by microfluid-based single-cell multiplex gene expression analysis. The ISC-specific function of organoid cells was evaluated using a single-cell organoid reformation assay.

RESULTS

ISC-marker genes, OLFM4 and SLC12A2, were expressed by an increased number of small intestinal epithelial cells in the active lesion of CD. aCD-SIOs, rCD-SIOs or those of non-IBD controls (NI-SIOs) were successfully established from 9 patients. Immunohistochemistry showed a comparable level of OLFM4 and SLC12A2 expression in all organoids. Single-cell gene expression data of 12 ISC-markers were acquired from a total of 1215 cells. t-distributed stochastic neighbor embedding analysis identified clusters of candidate ISCs, and also revealed a distinct expression pattern of SMOC2 and LGR5 in ISC-cluster classified cells derived from aCD-SIOs. Single-cell organoid reformation assays showed significantly higher reformation efficiency by the cells of the aCD-SIOs compared with that of cells from NI-SIOs.

CONCLUSIONS

aCD-SIOs harbor ISCs with modified marker expression profiles, and also with high organoid reformation ability. Results suggest modification of small intestinal stem cell properties by unidentified factors in the inflammatory environment of CD.

YAP/TAZ-Dependent Reprogramming of Colonic Epithelium Links ECM Remodeling to Tissue Regeneration

Tissue regeneration requires dynamic cellular adaptation to the wound environment. It is currently unclear how this is orchestrated at the cellular level and how cell fate is affected by severe tissue damage. Here we dissect cell fate transitions during colonic regeneration in a mouse dextran sulfate sodium (DSS) colitis model, and we demonstrate that the epithelium is transiently reprogrammed into a primitive state. This is characterized by de novo expression of fetal markers as well as suppression of markers for adult stem and differentiated cells. The fate change is orchestrated by remodeling the extracellular matrix (ECM), increased FAK/Src signaling, and ultimately YAP/TAZ activation. In a defined cell culture system recapitulating the extracellular matrix remodeling observed in vivo, we show that a collagen 3D matrix supplemented with Wnt ligands is sufficient to sustain endogenous YAP/TAZ and induce conversion of cell fate. This provides a simple model for tissue regeneration, implicating cellular reprogramming as an essential element.

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The repairing epithelium can be isolated based on Sca1 expression

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Markers upregulated during tissue repair are expressed in the fetal intestine

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Mechano-transduction via FAK, Src, and YAP/TAZ facilitate efficient tissue repair

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YAP/TAZ activation is required and sufficient to induce cellular reprogramming

Fluorescent labelling of intestinal epithelial cells reveals independent long-lived intestinal stem cells in a crypt

BACKGROUND AND AIMS

The dynamics of intestinal stem cells are crucial for regulation of intestinal function and maintenance. Although crypt stem cells have been identified in the intestine by genetic marking methods, identification of plural crypt stem cells has not yet been achieved as they are visualised in the same colour.

METHODS

Intestinal organoids were transferred into Matrigel® mixed with lentivirus encoding mCherry. The dynamics of mCherry-positive cells was analysed using time-lapse imaging, and the localisation of mCherry-positive cells was analysed using 3D immunofluorescence.

RESULTS

We established an original method for the introduction of a transgene into an organoid generated from mouse small intestine that resulted in continuous fluorescence of the mCherry protein in a portion of organoid cells. Three-dimensional analysis using confocal microscopy showed a single mCherry-positive cell in an organoid crypt that had been cultured for >1year, which suggested the presence of long-lived mCherry-positive and -negative stem cells in the same crypt. Moreover, a single mCherry-positive stem cell in a crypt gave rise to both crypt base columnar cells and transit amplifying cells. Each mCherry-positive and -negative cell contributed to the generation of organoids.

CONCLUSIONS

The use of our original lentiviral transgene system to mark individual organoid crypt stem cells showed that long-lived plural crypt stem cells might independently serve as intestinal epithelial cells, resulting in the formation of a completely functional villus.

Hes1 promotes the IL-22-mediated antimicrobial response by enhancing STAT3-dependent transcription in human intestinal epithelial cells

Notch signaling plays an essential role in the proliferation and differentiation of intestinal epithelial cells (IECs). We have previously shown that Notch signaling is up-regulated in the inflamed mucosa of ulcerative colitis (UC) and thereby plays an indispensable role in tissue regeneration. Here we show that in addition to Notch signaling, STAT3 signaling is highly activated in the inflamed mucosa of UC. Forced expression of the Notch target gene Hes1 dramatically enhanced the IL-22-mediated STAT3-dependent transcription in human IECs. This enhancement of STAT3-dependent transcription was achieved by the extended phosphorylation of STAT3 by Hes1. Microarray analysis revealed that Hes1-mediated enhancement of IL-22-STAT3 signaling significantly increased the induction of genes encoding antimicrobial peptides, such as REG1A, REG3A and REG3G, in human IECs. Conversely, the reduction of Hes1 protein levels with a γ-secretase inhibitor significantly down-regulated the induction of those genes in IECs, resulting in a markedly poor response to IL-22. Our present findings identify a new role for the molecular function of Hes1 in which the protein can interact with cytokine signals and regulate the immune response of IECs.

Transplantation of expanded fetal intestinal progenitors contributes to colon regeneration after injury

Regeneration and homeostasis in the adult intestinal epithelium is driven by proliferative resident stem cells, whose functional properties during organismal development are largely unknown. Here, we show that human and mouse fetal intestine contains proliferative, immature progenitors, which can be expanded in vitro as Fetal Enterospheres (FEnS). A highly similar progenitor population can be established during intestinal differentiation of human induced pluripotent stem cells. Established cultures of mouse fetal intestinal progenitors express lower levels of Lgr5 than mature progenitors and propagate in the presence of the Wnt antagonist Dkk1, and new cultures can be induced to form mature intestinal organoids by exposure to Wnt3a. Following transplantation in a colonic injury model, FEnS contribute to regeneration of colonic epithelium by forming epithelial crypt-like structures expressing region-specific differentiation markers. This work provides insight into mechanisms underlying development of the mammalian intestine and points to future opportunities for patient-specific regeneration of the digestive tract.

Lineage-specific expression of bestrophin-2 and bestrophin-4 in human intestinal epithelial cells

Intestinal epithelial cells (IECs) regulate the absorption and secretion of anions, such as HCO3^- or Cl^-. Bestrophin genes represent a newly identified group of calcium-activated Cl^- channels (CaCCs). Studies have suggested that, among the four human bestrophin-family genes, bestrophin-2 (BEST2) and bestrophin-4 (BEST4) might be expressed within the intestinal tissue. Consistently, a study showed that BEST2 is expressed by human colonic goblet cells. However, their precise expression pattern along the gastrointestinal tract, or the lineage specificity of the cells expressing these genes, remains largely unknown. Here, we show that BEST2 and BEST4 are expressed in vivo, each in a distinct, lineage-specific manner, in human IECs. While BEST2 was expressed exclusively in colonic goblet cells, BEST4 was expressed in the absorptive cells of both the small intestine and the colon. In addition, we found that BEST2 expression is significantly down-regulated in the active lesions of ulcerative colitis, where goblet cells were depleted, suggesting that BEST2 expression is restricted to goblet cells under both normal and pathologic conditions. Consistently, the induction of goblet cell differentiation by a Notch inhibitor, LY411575, significantly up-regulated the expression of not BEST4 but BEST2 in MUC2-positive HT-29 cells. Conversely, the induction of absorptive cell differentiation up-regulated the expression of BEST4 in villin-positive Caco-2 cells. In addition, we found that the up- or down-regulation of Notch activity leads to the preferential expression of either BEST4 or BEST2, respectively, in LS174T cells. These results collectively confirmed that BEST2 and BEST4 could be added to the lineage-specific genes of humans IECs due to their abilities to clearly identify goblet cells of colonic origin and a distinct subset of absorptive cells, respectively.

Delta-like 1 expression promotes goblet cell differentiation in Notch-inactivated human colonic epithelial cells

Notch signaling has previously been implicated in the regulation of the cell fate of intestinal epithelial cells. However, the expression and function of Notch ligands in the human intestine remain largely unknown. In the present study, we showed that Notch ligands Delta-like 1 (Dll1) and Delta-like 4 (Dll4) are expressed in a goblet cell-specific manner in human colonic tissue. Additionally, we found that Dll1 and Dll4 expression was regulated in-parallel with Atoh1 and MUC2, which are both under the control of the Notch-Hes1 signaling pathway. Because knockdown of Dll1 expression completely abrogated the acquisition of the goblet cell phenotype in Notch-inactivated colonic epithelial cells, we postulate that Dll1 might function as a cis-acting regulatory element that induces undifferentiated cells to become goblet cells. Our results suggest a link between Dll1 expression and human goblet cell differentiation that might be mediated by a function that is distinct from its role as a Notch receptor ligand.

Phase II study of a novel oral formation of 5-fluorouracil in combination with low-dose cisplatin as preoperative chemotherapy of oral squamous cell carcinoma

TS-1 is a novel oral 5-fluorouracil containing tegaful (prodrug of 5-FU) and two biochemical modulators. These modulators feature effect-enhancing and adverse reaction-reducing activity. We investigated the histological response and toxicities of combination chemotherapy with TS- 1 and low-dose cisplatin and evaluated its usefulness as preoperative chemotherapy Forty-four newly diagnosed patients with stage Il-IV oral squamous cell carcinoma were enrolled in this study from February 2002 to April 2004. Patients were administered TS-1 80 mg/m2/day (days 1-14) and cisplatin 5 mg/m2/day (days 1-5 and 8-12) followed by radical surgery within 2 weeks. The histopathological effect of chemotherapy, which was a surrogate endpoint of this trial, was evaluated with surgical or biopsy specimens. The rate of histological antitumor effect was as follows: complete response (CR) 36.4%, partial response (PR) 25.0%, minor response (MR) 18.1% and no change (NC) 20.5%. The rate of histological response (CR + PR) was 61.4%. The CR rate of effective cases was 59.3%. The main toxicities occurred in bone marrow and the digestive tract. The incidence of severe toxicity such as grade 3 or 4 was 4.5% in anemia, 9% in leukocytopenia, 11.4% in neutropenia, 4.5% in thrombocytopenia and 2.3% in anorexia, diarrhea and urticaria. Most patients showed no toxicity or mild toxicities. TS- 1 with low-dose cisplatin has highly effective antitumor activity and mild toxicities. In particular, the CR rate was very high. It is suggested that this regimen is suitable for neoadjuvant chemotherapy. We expect that this chemotherapy will contribute to avoidance of surgery for small tumors (stages I and II) and will enable function-preserving surgery for advanced tumors.

Macrophage-oriented cytotoxic activity of novel triterpene saponins extracted from roots of Securidaca inappendiculata

It is recognized that macrophages in peripheral tissues often proliferate under pathological conditions such as tumors, inflammation and atherosclerosis. Because the growth state of macrophages is believed to be a factor regulating the pathological process of the diseases, substances that regulate macrophage growth or survival may be useful for disease control. In this paper, we identified the activity inhibiting macrophage growth in a hot water extract of roots of Securidaca inappendiculata. The extract markedly inhibited macrophage colony-stimulating factor (M-CSF/CSF-1)-induced growth of macrophages, whereas it exerted a less potent effect on growth of Concanavalin A (Con A)-stimulated thymocytes or M-CSF-stimulated bone marrow cells. The inhibition of macrophage growth was caused by a cytotoxic effect rather than a cytostatic effect. Cell death was due to the induction of apoptosis, as judged by staining with terminal deoxynucleotidyl transferase-mediated d-UTP nick end labelling (TUNEL). The cytotoxic activity seemed to be specific to peripheral macrophages; it showed a weak effect on the growth and survival of tumor cell lines including a macrophage-like cell line, J-774.1. Moreover, the saponin fraction induced apoptotic cell death of macrophages only when they were stimulated by M-CSF; it did not affect the viability of macrophages cultured without M-CSF or with granulocyte/macrophage-CSF. We determined the structures of the two active triterpene saponin compounds in the fraction, named securioside A and securioside B having a 3,4-dimethoxycinnamic group which is essential for the cell death-inducing activity. They are believed to be the primary compounds of new drugs for the treatment of pathological states in which macrophage proliferation occurs.

Primary culture of porcine mammary epithelial cells as a model system for evaluation of milk protein expression

Porcine mammary epithelial cells were isolated to culture on collagen gel followed by gel floating treatment to evaluate differentiation under the culture conditions of serum-free medium, supplemented with combinations of insulin, hydrocortisone, and prolactin. After the culture period, the mammary cells attached to the collagen gels were recovered to observe expression of beta-casein, beta-lactoglobulin, and lactoferrin by reverse transcriptase polymeric chain reaction method. Expression of beta-casein was observed in the presence of insulin, hydrocortisone, and prolactin whereas transcription of beta-lactoglobulin and lactoferrin occured irrespective of hydrocortisone and prolactin. Immunoblot analysis demonstrated synthesis and secretion of lactoferrin in the fraction of recovered cells and the culture medium.

Securiosides A and B, novel acylated triterpene bisdesmosides with selective cytotoxic activity against M-CSF-stimulated macrophages

We report the discovery of securiosides A (1) and B (2), novel acylated triterpene bisdesmosides, isolated from the roots of Securidaca inappendiculata. Securiosides A and B showed potent selective cytotoxic activity against M-CSF-stimulated macrophages and were suggested to have potential as new agents for the treatment of inflammatory diseases such as RA and atherosclerosis.

[Inhibition effect of Amaryllidaceae alkaloids, lycorine and lycoricidinol on macrophage TNF-alpha production]

We previously demonstrated that Amaryllidaceae alkaloids, lycorine and lycoricidinol, inhibit induction of apoptosis by calprotectin derived from neutrophils, and that the latter alkaloid showed suppression in rat adjuvant-induced arthritis model. These findings suggest that the alkaloids have a modulating activity against inflammatory reaction. To explore further the mechanism of the suppression for inflammation, we studied the effect of the alkaloids on macrophage tumor necrosis factor (TNF-alpha) production in vitro, since TNF-alpha is recognized as a pivotal cytokine to regulate inflammation. As a result of this study, lycorine and lycoricidinol inhibited TNF-alpha production of murine macrophages stimulated with lipopolysaccharide (ID50 were 0.2 microgram/ml and 0.002 microgram/ml, respectively). The inhibition was also observed in macrophages treated by Gram-positive bacteria, Enterococcus faecalis. Both lycorine and lycoricidinol reportedly have inhibitory activity for protein biosynthesis. Although the inhibition of TNF-alpha production by lycoricidinol was mainly due to the inhibition of protein biosynthesis, lycorine showed inhibition against TNF-alpha production at lower concentrations than the case that they inhibited 35S-Cysteine/35S-Methionine incorporation into macrophages. These facts suggest that the inhibition of TNF-alpha production is not due to the inhibitory activity against protein translation at least at lower concentrations. From these results, it was concluded that these alkaloids exert inhibitory effects not only on neutrophil apoptosis-inducing protein, calprotectin, but also on macrophage TNF-alpha production.

Induction of GM-CSF production of macrophages by advanced glycation end products of the Maillard reaction

We previously reported that AGEs can induce macrophage growth. In this paper, we examined whether advanced glycation end products (AGE) of protein induced GM-CSF production of macrophages. AGE of bovine serum albumin markedly stimulated not only the expression of GM-CSF mRNA, but also GM-CSF secretion in macrophage supernatant. Thus GM-CSF is suggested to be an endogenous signal for macrophage growth induction by AGEs.

The effects of interleukin (IL)-4 and IL-10 on macrophage growth-stimulating activities of oxidized low density lipoprotein (LDL), acetylated LDL and macrophage colony-stimulating factor: the activity of oxidized LDL is refractory to the inhibitory cytokines

We have previously reported that ligands of scavenger receptor such as acetylated low density lipoprotein (acetyl-LDL) and oxidized LDL induced growth of peripheral macrophages in vitro. This suggests the possibility that in addition to foam cell formation, modified or oxidized LDLs induce macrophage proliferation in atherosclerotic lesions. To learn further the physiological regulation of macrophage growth, we comparatively examined the effect of interleukin (IL)-4 and IL-10 which have been reported to be suppressive to various macrophage functions on macrophage growth-stimulating activities of the acetyl-LDL, oxidized LDL and macrophage colony-stimulating factor (M-CSF). An in vitro study showed that the activity of M-CSF-containing L-cell-conditioned medium was the most sensitive to the suppressive effects of these cytokines. The growth-inducing activity of acetyl-LDL was significantly inhibited by both IL-4 and IL-10. On the other hand, the activity of oxidized LDL was not attenuated by IL-4 or IL-10. These data indicate that macrophage growth-stimulating activity of oxidized LDL, in contrast to that of M-CSF or acetyl-LDL, is refractory to these suppressive cytokines. Oxidized LDL may act as a potent macrophage growth-stimulating factor in atherosclerotic or other inflammatory sites, even when these cytokines are produced by inflammatory and immunological reactions in situ.

Suppressive activity of lycoricidinol (narciclasine) against cytotoxicity of neutrophil-derived calprotectin, and its suppressive effect on rat adjuvant arthritis model

Calprotectin is a calcium- and zinc-binding protein complex that is abundant in cytosol of neutrophils. The concentration of calprotectin in extracellular fluids is greatly increased under various inflammatory conditions in vivo. We recently demonstrated that calprotectin inhibited cell growth and induced apoptosis of various cell types including tumor cells and normal fibroblasts; therefore, extracellular calprotectin might cause tissue destruction in severe inflammatory diseases. We previously found that an alkaloid, lycorine inhibits induction of apoptosis by calprotectin. In this paper, we examined the inhibitory activities of other Amaryllidaceae alkaloids, namely, lycoricidinol, hippeastrine and ungerine against the cytotoxicity of calprotectin. Lycoricidinol (narciclasine) inhibited calprotectin-induced cytotoxicity at more than 10-fold lower concentration (IC50=0.001-0.01 microg/ml) than lycorine, while the effects of the latter two alkaloids were very weak. Therefore, we next checked the prophylactic effect of lycorine and lycoricidinol on the adjuvant arthritis model in rats. Lycoricidinol, but not lycorine, significantly suppressed the degree of swelling of adjuvant-treated as well as untreated feet, suggesting that lycoricidinol might be a candidate as a the drug having marked suppressive activity for inflammation which might be influenced by calprotectin.

Anti-Candida activity of calprotectin in combination with neutrophils or lactoferrin

The effect of an anti-microbial protein, calprotectin, in combination with neutrophils on the growth of Candida albicans was investigated. The growth inhibition of C. albicans by murine neutrophils was augmented by the addition of a low concentration of calprotectin prepared from rat peritoneal exudate cells. The concentrations of calprotectin causing 50% inhibition of growth of C. albicans in the absence or presence of neutrophils at an effector-to-target (E/T) ratio of 30 and 60 were estimated to be 0.45, 0.34 and 0.28 U/ml, respectively. The anti-Candida activity of calprotectin was completely inhibited by 2 microM of zinc ion, while it only partially lowered the activity of the combination of calprotectin and neutrophils. Lactoferrin, which is an anti-microbial protein released from neutrophils, strongly inhibited the growth of C. albicans in combination with calprotectin. These results suggest that calprotectin and lactoferrin released from neutrophils may cooperate to inhibit the growth of C. albicans at a local lesion of the infection where there is an accumulation of neutrophils.

The inhibitory effect of lycorine on tumor cell apoptosis induced by polymorphonuclear leukocyte-derived calprotectin

We recently demonstrated that calprotectin, an abundant calcium-binding protein complex in polymorphonuclear leukocytes (PMNs), has the capacity to induce growth inhibition and apoptotic cell death against a variety of tumor cell lines and normal cells such as fibroblasts. Therefore, calprotectin which is released to extracellular spaces, might cause tissue destruction in severe inflammatory conditions. In search of drugs to suppress the cytotoxic effects of calprotectin, we screened plant products that have been used as Chinese medicines. Using MM46 mouse mammary carcinoma cells as targets, we found that hot water extracts of Crinum asiaticum showed strong inhibition of calprotectin-induced cytotoxicity in vitro. By purification studies, we identified the alkaloid, lycorine, as the active inhibitory molecule. Lycorine inhibits not only induction of MM46 cell death by calprotectin but also inhibits the suppressive effect of calprotectin on target DNA synthesis at a half effective concentration of 0.1-0.5 microg/ml. Lycorine has been reported to posses inhibitory activity against protein translation. Since we previously showed that target protein synthesis is necessary for induction of cell death and that calprotectin actually upregulates the net protein synthesis of MM46 cells, we compared the dose-response relationship between the inhibitory effects of lycorine on calprotectin action and target protein synthesis. Although 1 microg/ml lycorine did not bring about marked inhibition of protein synthesis in MM46 cells without calprotectin, it attenuated the protein synthesis that was augmented by calprotectin to the level of protein synthesis in cells not treated with calprotectin. These results suggest that lycorine inhibition for calprotectin cytotoxicity is not solely due to its inhibitory effect on protein synthesis.

Kinetical analysis of tumor cell death-inducing mechanism by polymorphonuclear leukocyte-derived calprotectin: involvement of protein synthesis and generation of reactive oxygen species in target cells

We have previously shown that calprotectin, the most abundant cytosolic protein existing in polymorphonuclear leukocytes (PMNs), induces apoptotic cell death in various tumor cells, suggesting that calprotectin is an effector molecule against tumor cells in PMNs. To explore the cell death-inducing mechanism of the factor, we examined the involvement of target protein synthesis and generation of reactive oxygen species (ROS) in the reaction. Calprotectin induced cell death in MM46 mouse mammary carcinoma cells after a 14-16 hr lag time. When the factor was removed from the medium up to about 12 hr after culturing, the effect was diminished. The induction of cell death by calprotectin was markedly inhibited by the presence of the RNA synthesis inhibitor actinomycin D or the protein synthesis inhibitor cycloheximide. However, the addition of these inhibitors after 12 hr of culturing was unable to inhibit the reaction. Up to 12 hr of culturing, the net protein synthesis of MM46 cells was augmented by the presence of calprotectin, but thereafter was impaired. The induction of cell death was also inhibited by the antioxidative reagents N-acetyl-L-cysteine (NAC) or propyl gallate. The addition of NAC even 15 hr later significantly attenuated the calprotectin effect. Flow cytometry analysis showed that calprotectin began to increase the ROS content in MM46 cells after 8-12 hr of culturing, and that the increase was abrogated by the antioxidants. Thus, protein synthesis and ROS generation may be essential elements in the early or later phases of the cell death-inducing reaction of calprotectin, respectively.

Growth-inhibitory and apoptosis-inducing activities of calprotectin derived from inflammatory exudate cells on normal fibroblasts: regulation by metal ions

We have shown previously that a calcium-binding protein complex, calprotectin, derived from polymorphonuclear leukocytes exerts a cytostatic and cytolytic effect against a very broad range of tumor cell lines. We also described that calprotectin is an apoptosis-inducing factor for certain tumor cells and that zinc ion attenuates the calprotectin activities. The titers of the factor in body fluids are known to increase greatly in various types of inflammation. In this study, to learn the role of calprotectin in inflammation, the growth-inhibitory and the apoptosis-inducing activities of the factor against normal fibroblasts were examined because fibroblasts are a cell type constituting a local inflammatory site. Rat calprotectin inhibited the growth of murine embryonic as well as human dermal fibroblasts. Although calprotectin induced apoptotic morphology in both fibroblasts, the reaction was slower and less efficient than cases using tumor cells as targets. The activities were significantly abrogated by 10-50 microM Zn2+, Cu2+, Mn2+, or Fe2+, respectively, whereas the trivalent cations Al3+ and Fe3+ had no effect. The dose-response curves of the calprotectin effects were shifted to about 10-fold lower concentration ranges in the divalent metal ion-depleted medium. These results suggest that calprotectin extracellularly affects the inflammatory processes by modulating the growth and survival states of normal fibroblasts, and that the effects are physiologically controlled by several metal ions.

Stimulation of macrophage DNA synthesis by polyanionic substances through binding to the macrophage scavenger receptor

We previously demonstrated that ligands of macrophage scavenger receptors such as acetylated low density lipoprotein (LDL), oxidized LDL and advanced glycation-end products (AGE) of the Maillard reaction induce the growth of peritoneal exudate macrophages, and that the activity of AGE is inhibited by the presence of an antibody for granulocyte/macrophage colony-stimulating factor (GM-CSF). To evaluate the suggested role of the scavenger receptor in the induction of macrophage growth, we compared the effect of various polyanionic compounds which were reported to either have or not to have competent activity for the binding of acetylated LDL to scavenger receptors on macrophage DNA synthesis. Among the polyanions exhibiting such activity, polyguanilic acid (poly G) and dextran sulfate strongly augmented macrophage DNA synthesis, although they did not increase macrophage cell number. On the other hand, polyanions which are not ligands for the scavenger receptors did not show a significant augmenting effect, suggesting that the binding of polyanions to the scavenger receptor is important but not, by itself, sufficient. The augmentation of DNA synthesis in macrophages cultured with dextran sulfate or poly G was inhibited by the co-presence of anti-GM-CSF antibody, suggesting that the reaction is mediated by GM-CSF. However, dextran sulfate did not augment the production of GM-CSF in macrophages. Therefore, GM-CSF spontaneously present in macrophages might be a prerequisite for the induction of DNA synthesis.

Induction of apoptotic cell death in mouse lymphoma and human leukemia cell lines by a calcium-binding protein complex, calprotectin, derived from inflammatory peritoneal exudate cells

We have previously shown that the calcium-binding protein complex, calprotectin, purified from rat inflammatory peritoneal cells exerts marked cytotoxic activity against rat, mouse, and human tumor cells. We studied here whether the cytotoxicity is caused by induction of apoptosis, using mouse EL-4 lymphoma and human MOLT-4 leukemia lines as targets. The rat calprotectin sample inhibited [3H]thymidine incorporation into these cells by partially 24 h and almost completely in 48 h of culture at concentrations of 100-200 micrograms/ml. Morphological changes, that is, loss of cell volume and nuclear condensation and/or fragmentation, appeared in both cell types cultured with calprotectin from 20 h, and such apoptotic cells subsequently increased in number to compose the great majority of the cells at 40 h. Cell death, measured by stainability with trypan blue, lagged behind the emergence of the apoptotic morphology by about 2 and 10 h in EL-4 and MOLT-4 cells, respectively. DNA fragmentation was observed in EL-4 cells cultured with calprotectin, whereas it was not observed in MOLT-4 cells, consistent with results of flow cytometry showing that loss of cell DNA content caused by the factor was greater in EL-4 cells. The data indicate that calprotectin induces the apoptosis of certain tumor cells but that the occurrence of DNA fragmentation is dependent on cell type. Finally, the apoptosis-inducing activity of the calprotectin sample was abrogated by the presence of 10 microM zinc, whereas it was not affected by 5 mM calcium or magnesium.

Purification and characterization of the cytotoxic factor in rat peritoneal exudate cells: its identification as the calcium binding protein complex, calprotectin

We previously reported the existence of a growth inhibitory factor for mitogen-stimulated lymphocytes and murine tumor cell lines, MM46 and L-929, in inflammatory polymorphonuclear leukocytes. In this study, by using mouse MM46 mammary carcinoma as target, we purified the inhibitor from lysate of rat inflammatory peritoneal exudate cells by ammonium sulfate precipitation, gel filtration, isoelectrofocusing, and anion exchange chromatography. Although the in vitro inhibitory activity for MM46 growth was partitioned into three peaks in the final step, it was found that these inhibitory samples all consist of 8- and 13-kDa peptides. Analysis of amino acid sequences revealed that the partial sequences of the 8- and 13-kDa peptides completely agree with the smaller and larger components of rat calprotectin, which are predicted from cDNA, respectively, suggesting the cell growth inhibitory factor is calprotectin. In addition to MM46, the partially purified calprotectin inhibited the growth of a rat, three mice, and a human tumor cell line in similar dose-response relationships in vitro. Moreover, it exerted a cytolytic effect against all examined tumor cells. It was confirmed that the purified calprotectin induces growth inhibition and the lysis of MM46 cells and that the minimum effective concentration is between 50 and 100 micrograms/ml. The factor also inhibited the growth of bone marrow cells and macrophages. These results suggest that calprotectin is a negative regulatory factor for the growth and/or survival states of normal and tumor cells.

Lysophosphatidylcholine plays an essential role in the mitogenic effect of oxidized low density lipoprotein on murine macrophages

We previously demonstrated that the growth of starch-induced murine macrophages was stimulated by modified low density lipoproteins, such as oxidized low density lipoprotein (Ox-LDL) and acetylated low density lipoprotein (acetyl-LDL), and that the mitogenic effect of Ox-LDL was much greater than that of acetyl-LDL (Yui, S., Sasaki, T., Miyazaki, A., Horiuchi, S., and Yamazaki, M. (1993) Arterioscler. Thromb. 13, 331-337). The present study was undertaken to elucidate the factor(s) that are involved in this growth-stimulating effect of Ox-LDL. The growth-stimulating effect of acetyl-LDL on murine resident macrophages was negligibly weak compared with that of Ox-LDL. However, the treatment of acetyl-LDL with phospholipase A2 led to an increase in lysophosphatidylcholine (lyso-PC) (75% of total phospholipids) and a concomitant increase in the mitogenic activity of acetyl-LDL. In contrast, cell-free incubation of Ox-LDL with high density lipoprotein resulted in a decrease in lyso-PC content and a concomitant loss of growth-stimulating activity. These results suggest that lyso-PC may play an essential role in the mitogenic activity of Ox-LDL.

Induction of macrophage growth by advanced glycation end products of the Maillard reaction

We previously showed that negatively-charged phospholipids, acetylated low density lipoprotein (LDL) and oxidized LDL, which are known to be taken up by macrophages via the scavenger receptor for modified LDLs, were able to induce the growth of peripheral macrophages in vitro. The present study demonstrated the macrophage growth-stimulating activity of the ligands for another macrophage receptor for advanced glycation end products (AGE) of the Maillard reaction. Experiments with murine macrophages showed that significant cell growth was induced by AGE-modified proteins such as bovine serum albumin (AGE-BSA) and AGE-human hemoglobin. The capacity of AGE-BSA to induce macrophage growth was completely blocked when cells were cultured with the mAb against granulocyte/macrophage CSF (GM-CSF). Moreover, PCR analysis revealed that AGE-BSA induced the expression of mRNA of GM-CSF. These data suggest that the macrophage AGE receptor may play an active role not only in phagocytic elimination of AGE-proteins but also induction of the growth of macrophages.

Induction of macrophage growth by advanced glycation end products of the Maillard reaction

We previously showed that negatively-charged phospholipids, acetylated low density lipoprotein (LDL) and oxidized LDL, which are known to be taken up by macrophages via the scavenger receptor for modified LDLs, were able to induce the growth of peripheral macrophages in vitro. The present study demonstrated the macrophage growth-stimulating activity of the ligands for another macrophage receptor for advanced glycation end products (AGE) of the Maillard reaction. Experiments with murine macrophages showed that significant cell growth was induced by AGE-modified proteins such as bovine serum albumin (AGE-BSA) and AGE-human hemoglobin. The capacity of AGE-BSA to induce macrophage growth was completely blocked when cells were cultured with the mAb against granulocyte/macrophage CSF (GM-CSF). Moreover, PCR analysis revealed that AGE-BSA induced the expression of mRNA of GM-CSF. These data suggest that the macrophage AGE receptor may play an active role not only in phagocytic elimination of AGE-proteins but also induction of the growth of macrophages.

Characterization of cell growth-inhibitory factor in inflammatory peritoneal exudate cells of rats

We characterized the nature and reaction mode of the cell growth-inhibitory factor (here designated CGIF) from rat peritoneal exudate cells (PEC). The soluble fraction separated from the lysate of Enterococcus faecalis-induced 24 hr PEC completely inhibited Con A-induced thymocyte mitogenesis. Gel filtration chromatography showed that CGIF has a molecular weight of approximately 23-25 kDa. Isoelectric focusing with Rotofor indicates that the factor has an isoelectronic point of 5.8-6.4. CGIF was inactivated by treatment at 70 C, for 30 min or by tryptic digestion, but the activity was not destroyed by the reduction with dithiothreitol. As well as thymocyte proliferation, CGIF completely suppressed 3H-thymidine incorporation of splenocytes which were stimulated by either Con A or LPS, suggesting the factor is effective on both T and B cells. The acting point of the inhibitor appeared to be a later stage of the lymphocyte activation sequence, since it was still effective when added 28.5 hr after the addition of Con A. CGIF also reduced the viability of these cells when added with mitogens such as Con A or LPS. CGIF thus appears to be distinct from interleukin-1 receptor antagonist or transforming growth factor-beta.

Heat stable interleukin-1 activity and activity inhibiting thymocyte proliferation in inflammatory polymorphonuclear leukocytes

The present study demonstrates the co-existence of heat stable interleukin-1 (IL-1) and IL-1-suppressing activity in murine inflammatory polymorphonuclear leukocytes (PMNs). When the IL-1 activity in casein-induced PMN lysate was examined by lymphocyte activating factor assay, it peaked at a concentration of 2.5 x 10(6) cells per ml, but this activity was reduced to nothing at higher concentrations, suggesting the co-existence of IL-1 and IL-1-suppressive factors in PMNs. Although IL-1 has been reported to be inactivated by heat treatment, approximately one-fourth of the IL-1 activity was restored after treatment at 100 degrees C for 10 min. In gel chromatography, the IL-1 activity of the PMN-soluble fraction was eluted in two broad peaks with apparent molecular sizes of 17-23 kDa and 23-43 kDa, respectively. Since the heat stable IL-1 activity was mainly eluted in fractions corresponding to the latter peak, and was neutralized by IL-1 receptor antagonist (IL-1ra) or anti-IL-1 alpha antiserum, the heat stable IL-1 is suggested to be precursor form IL-1 alpha. A high concentration of soluble fraction from PMN lysate, in contrast, completely suppressed the activity of recombinant IL-1 alpha or beta, and the suppressive activity was heat labile. Since thymocyte mitogenesis by 5 micrograms/ml of concanavalin A (Con A) with or without IL-2 was also completely suppressed, the suppressive factor(s) may not be IL-1ra or transforming growth factor beta which were reported to be present in PMNs.

Augmentation and suppression of TNF release from macrophages by inflammatory polymorphonuclear leukocytes

It is known that polymorphonuclear leukocytes (PMNs) emerge first in local inflammatory sites, and then they are followed and scavenged by macrophages. We focused on the effect of PMN on tumor necrosis factor (TNF) release activity of macrophages, which is viewed as a possible indicator of the status of macrophage activation. One day after macrophages were cultured with fresh, intact murine PMNs which were induced with sodium casein, the release of TNF triggered by lipopolysaccharide (LPS) was augmented by low concentrations of PMNs, but suppressed by their high concentrations. When the PMN samples were fractionated into soluble and insoluble fractions, the augmenting and suppressing activity was partitioned; the relatively high concentrations of soluble fraction showed the suppressive effect whereas the insoluble fraction in lower concentrations showed augmentation. The suppressive activity was stable at 100 C, but the filtrates of the soluble fraction with membranes having cut-offs of 5,000 or 10,000 were not suppressive at all, suggesting the suppression is not due to low molecular compounds. It was also suggested that the suppressive effect for TNF release was not due to contaminating LPS or transforming growth factor-beta. Inflammatory processes may thus be positively and negatively controlled by a quantitative factor of initial PMN populations by regulating the TNF release activity of the subsequent macrophages.

Induction of murine macrophage growth by modified LDLs

We previously reported that cell membrane components and lipoproteins were able to induce the growth of murine peritoneal macrophages. The aim of the present study was to examine whether macrophage growth could also be induced by chemically modified lipoproteins, such as acetylated low density lipoprotein (acetyl-LDL) or oxidized LDL, ligands known to be endocytosed by the macrophage scavenger receptors. When murine peritoneal exudate macrophages were cultured in vitro with 25-100 micrograms/mL acetyl-LDL or oxidized LDL, significant growth was induced. On comparing the dose-response curves of these LDLs, a more potent effect was seen with oxidized LDL than acetyl-LDL, especially on resident macrophages. On the other hand, growth of these cells was not stimulated by native (unmodified) LDL or high density lipoprotein. These in vitro data revealed a new function of chemically modified LDLs as effective inducers of macrophage cell growth. This aspect may be physiologically relevant to the growth of macrophage foam cells in situ in the development of atherosclerosis.

Augmentation and suppression of release of tumor necrosis factor from macrophages by negatively charged phospholipids

We recently reported that some lipid species of cell membranes and lipoproteins induced the growth of peripheral macrophages. In this study, the effects of phospholipids on tumor necrosis factor (TNF)-releasing activity of macrophages were examined. Ten to 20 micrograms/ml of cardiolipin, which is a suboptimal concentration for macrophage growth-stimulation, augmented macrophage TNF release triggered by lipopolysaccharide (LPS) in vitro. This priming effect appeared with 1 day of preincubation and was still potent on day 3, whereas the priming effect of interferon-gamma (IFN-gamma) peaked at 3 h and then gradually decreased. In contrast, a high concentration of cardiolipin (40 micrograms/ml) which is optimal for the induction of macrophage growth, completely suppressed LPS-triggered TNF release from not only untreated macrophages but also IFN-gamma-primed macrophages. The suppressive effect was potent even with 3 h preincubation, was still potent on day 3, and was not abolished by indomethacin. Cardiolipin had scarcely any effect on the triggering activity of LPS. Similar augmentative and suppressive activities were observed in peroxidized phosphatidylserine, which is also highly active in inducing macrophage growth, but was not found in native phosphatidylserine, which is less active in inducing macrophage growth, but was not found in native phosphatidylserine, which is less active, nor in phosphatidylcholine, which is an inactive species toward macrophage growth. These results suggest that lipids may be important endogenous factors in regulating both activation and growth states of peripheral macrophages.