Reactive cutaneous capillary endothelial proliferation predicted the efficacy of camrelizumab in patients with recurrent/metastatic head and neck squamous cell carcinoma

BACKGROUND

Reactive cutaneous capillary endothelial proliferation (RCCEP), a special adverse event (AE) only observed in patients treated with camrelizumab, was reported to be correlated with the efficacy of camrelizumab in patients with advanced hepatocellular carcinoma. This study to analyze the possible correlation between the occurrence of RCCEP and efficacy of camrelizumab in patients with recurrent/metastatic head and neck squamous cell carcinoma (R/M HNSCC).

MATERIAL AND METHODS

In this study, we retrospectively analyzed the efficacy and RCCEP occurrence of camrelizumab in 58 patients with R/M HNSCC in the Shanghai Ninth People's Hospital affiliated to Shanghai JiaoTong University School of Medicine between January 2019 and June 2022. Kaplan-Meier analysis was used to assess the correlation between the occurrence of RCCEP and the survival of enrolled patients, and COX multifactor analysis was adopted to evaluate associated factors that affected the efficacy of camrelizumab immunotherapy.

RESULTS

A significant correlation between the incidence of RCCEP and a higher objective response rate was observed in this study (p=0.008). The occurrence of RCCEP was associated with better median overall survival (17.0 months vs. 8.7 months, p<0.0001, HR=5.944, 95% CI:2.097-16.84) and better median progression-free survival (15.1 months vs. 4.0 months, p<0.0001, HR=4.329,95% CI:1.683-11.13). In COX multifactor analysis, RCCEP occurrence was also an independent prognostic factor affecting OS and PFS in patients with R/M HNSCC.

CONCLUSIONS

The occurrence of RCCEP can show a better prognosis, it could be used as a clinical biomarker to predict the efficacy of camrelizumab treatment.

Development and Validation of a Deep Learning-Based Auto-Delineation of Target Volume and Organs at Risk in Pancreatic Cancer Radiotherapy

PURPOSE/OBJECTIVE(S)

The delineation of the clinical target volume (CTV), gross target volume (GTV) and organs at risk (OARs) is a crucial and laborious in pancreatic cancer radiotherapy. In this work, we propose and evaluate a three-dimensional (3D) novel convolutional neural network (CNN) for automatic and accurate CTV, GTV and OARs in pancreatic cancer.

MATERIALS/METHODS

A total of 120 computed tomography (CT) scans patients with pancreatic cancer were collected. A novel 3D CNN network, called ResUNet3D, was developed to achieve auto-delineation. 96 patients chosen randomly were used for training, 12 patients for validation, and 12 patients for testing. Meanwhile, the Dice similarity coefficient (DSC) and 95th percentile Hausdorff distance (HD95%) were used to assess the performance.

RESULTS

The DSC values for the test data were 80.9±8.6%, 77.5±5.6%, 94.5±1.3%, 66.2±13.4%, 73.6±7.6%, 79.0±8.7%, 94.1±1.9%, 94.6±1.4%, 87.3±5.8% for CTV, GTV, liver, duodenum, spinal cord, bowel, kidney left, kidney right, stomach. The corresponding HD95% values were 10.7±6.9mm, 7.8±5.7mm, 11.6±5.6mm, 18.6±5.6mm, 2.7±0.7mm, 17.7±8.6mm, 3.9±1.4mm, 3.7±1.9mm, 13.4±5.7mm, respectively. The average delineation time for one patient's CT images was within 5 seconds.

CONCLUSION

The experimental results demonstrate that the CTV, GTV and OARs delineated for pancreatic cancer by ResUNet3D achieved a close agreement with the ground truth. ResUNet3D could significantly reduce the radiation oncologists' contouring time.

Exploration of AI-Assisted On-Board Perfusion Imaging Technique on Patients Undergoing Thoraxradiotherapy

PURPOSE/OBJECTIVE(S)

Pulmonary function of lung cancer patients can significantly change along the radiation therapy (RT) course. Scholars have synthesized lung function maps from computed tomography (CT) images. Still, there is lack of study exploring the feasibility of generating lung perfusion information from cone-beam CT (CBCT). Our study aims to fill up this gap in the body of literatures.

MATERIALS/METHODS

One-hundred-and-six pairs of planning CT and CBCT images of thoracic cancer patients from XX hospital were collected retrospectively. All CT images were registered to CBCT with a deformable algorithm, and referred as deformed planning CT (dCT). A 2D convolutional neural network (CNN) model built with cycle generative adversarial network (cycle-GAN) was trained to correct CBCT image artifacts and HU value discrepancies. The corrected CBCT was named enhanced CBCT (eCBCT) in this study. All CBCT, eCBCT and dCT images were then input to a pre-trained CT-to-perfusion deep learning (DL) model to synthesize perfusion images (PI), namely PICBCT, PIeCBCT and PIdCT respectively. For model training, 80 image pairs were assigned to the training set while others to the testing set. dCT and PIdCT were respectively regarded as the ground truth in two consecutive models. One extra validation case acquired with SPECT perfusion scan was collected for model performance test. Quantitative evaluation was done between the ground truth and the synthesized images. Peak signal-to-noise ratio (PSNR) and mean absolute error (MAE) were computed to assess efficacy of CBCT enhancement. Correlation (R) and Dice similarity coefficient (DSC) were used to evaluate voxel-wise and function-wise concurrence in CBCT-derived perfusion mapping.

RESULTS

In CBCT enhancement, [eCBCT-dCT] pairs demonstrated higher agreement than [CBCT-dCT] pairs. Quantitatively, PSNR and MAE were improved from 21.10±1.60 to 24.08±1.76, and 68.99±13.51 to 47.06±11.31 (p<0.01), respectively. For perfusion translation, higher correlation was demonstrated in both voxel-wise and function-wise evaluation within [PIeCBCT-PIdCT] than [PICBCT-PIdCT]. R correlation increased from 0.84±0.09 to 0.89±0.06 (p<0.01), whereas DSC in high-functional regions increased from 0.77±0.06 to 0.82±0.05 (p<0.01). In the validation case, strong correlation was observed between SPECT perfusion scan and PIeCBCT, with R increasing from 0.57 to 0.65 when compared to PICBCT.

CONCLUSION

We proposed a novel DL framework that synthesized perfusion images from fractionally acquired CBCT. Our framework met the clinical needs in providing real-time lung perfusion maps. It can be used to track the continuously changing pulmonary function status throughout the RT course using routinely scanned CBCT, without additional imaging modalities. The framework can facilitate functionally guided adaptive radiation therapy by providing immediate pulmonary function information.

MicroRNA-29a-3p regulates chemosensitivity in hypopharyngeal carcinoma via targeting Cdc42

INTRODUCTION

Hypopharyngeal carcinoma is one kind of high malignant tumour followed by poor prognosis in head and neck carcinomas. This study aimed to detect miR-29a-3p and Cdc42 in patients with hypopharyngeal carcinoma.

MATERIALS AND METHODS

The expression of miR-29a-3p and Cdc42 mRNA were detected, and the correlation between miR-29a-3p/Cdc42 and clinical stages was investigated.

RESULTS

The relative expression of miR-29a-3p in stage II, III and IV hypopharyngeal carcinoma tissues was significantly lower than that of stage I (P< 0.05). The relative expression of Cdc42 mRNA in stage I, III and IV tissues was significantly higher than that of stage I (P< 0.05). The expression of miR-29a-3p in hypopharyngeal carcinoma with lymph node metastasis was significantly lower than that without lymph node metastasis (P = 0.045).

CONCLUSION

MiR-29a-3p and Cdc42 mRNA could be potential diagnostic biomarkers of hypopharyngeal carcinoma.

Population structure and genetic diversity of four Henan pig populations

To investigate the population structure and genetic diversity of Henan indigenous pig breeds, samples from a total of 78 pigs of 11 breeds were collected, including four pig populations from Henan Province, three Western commercial breeds, three Chinese native pig breeds from other provinces and one Asian wild boar. The genotyping datasets were obtained by genotyping-by-sequencing technology. We found a high degree of polymorphism and rapid linkage disequilibrium decay in Henan pigs. A neighbor-joining tree, principal component analysis and structure analysis revealed that the Huainan and Erhualian pigs were clustered together and that the Queshan black pigs were clearly grouped together but that the Nanyang and Yuxi pigs were extensively admixed with Western pigs. In addition, heterozygosity values might indicate that Henan indigenous pigs, especially the Queshan black and Huainan pigs, were subjected to little selection during domestication. The results presented here indicate that Henan pig breeds were admixed from Western breeds, especially Nanyang and Yuxi pigs. Therefore, establishment of purification and rejuvenation systems to implement conservation strategies is urgent. In addition, it is also necessary to accelerate genetic resources improvement and utilization using modern breeding technologies, such as genomic selection and genome-wide association studies.

Serum cartilage oligomeric matrix protein (COMP) expression in individuals who sustained a youth sport-related intra-articular knee injury 3-10 years previously and uninjured matched controls

OBJECTIVE

This study investigates the relationship between a youth sport-related intra-articular knee injury and cartilage oligomeric matrix protein (COMP), a biomarker of cartilage turnover.

DESIGN

Participants included a sub-sample (n = 170) of the Alberta Youth Prevention of Early Osteoarthritis (PrE-OA) study group. Specifically, 85 individuals with a 3-10 year history of sport-related intra-articular knee injury and 85 age, sex and sport-matched controls. COMP levels were investigated in serum. Between group differences in COMP levels, COMP fragmentation patterns and, the relationship between serum COMP and clinical outcomes (i.e., Magnetic Resonance Imaging (MRI) Osteoarthritis Knee Score; MOAKS, Knee Osteoarthritis Outcome Score; KOOS, Fat mass index; FMI) were examined.

RESULTS

Participant median age was 22.3 years (range 16-26) and 63% were female. Although there was no difference in COMP levels between previously injured and uninjured females, previously injured males demonstrated an ∼15% greater (171.5 ng/ml, 95% CI 11.0-428.0, P = 0.04) serum COMP level than uninjured males. However after controlling for FMI, this difference was absent. Within the injured participants, COMP levels were associated with MOAKS_SYNOVITIS and FMI. Furthermore, COMP fragmentation patterns were distinct between injured and uninjured individuals.

CONCLUSIONS

In this study group, serum COMP levels were greater in injured males, but not females, compared to matched controls. However, after controlling for FMI, no differences in COMP were observed. A unique COMP fragmentation pattern was observed in injured vs uninjured participants. These results further the hypothesis that COMP levels and/or degradation of the protein may be a marker of cartilage injury which could predispose to later OA.

CCL22 is a biomarker of cartilage injury and plays a functional role in chondrocyte apoptosis

BACKGROUND

Osteoarthritis (OA) is one of the leading causes of disability worldwide. Previous history of knee injury is a significant risk factor for OA. It has been established that low-level chronic inflammation plays a pivotal role in the onset and pathogenesis of OA. The primary aim of this research was to determine if a history of knee joint injury is associated with systemic inflammation. A secondary aim was to determine if systemic inflammation is related to knee pain and joint structure.

METHODS

Differences in serum cytokine association networks, knee joint structural changes (MRI), and self-reported pain (i.e., Knee Injury and Osteoarthritis Outcome Score Pain subscale, KOOS_PAIN and Intermittent and Constant Osteoarthritis Pain score, ICOAP) between individuals who had sustained a youth (aged 15-26 years) sport-related knee injury 3-10 years previously and age- and sex-matched controls were examined. Proteins of interest were also examined in an OA rat model.

RESULTS

Cytokine association networks were found to differ significantly between study groups, yet no significant associations were found between networks and KOOS_PAIN or MRI-defined OA. A group of cytokines (MCP1/CCL2, CCL22 and TNFα) were differentially associated with other cytokines between study groups. In a pre-clinical rat OA model, serum CCL22 levels were associated with pain (r = 0.255, p = 0.045) and structural changes to the cartilage. CCL22 expression was also observed in human OA cartilage and furthermore, CCL22 induced apoptosis of isolated human chondrocytes.

DISCUSSION

These results suggest that CCL22 may be an early factor in the onset/pathogenic process of cartilage degeneration and/or related to pain OA.

[Genetic characterization of rubella virus isolated in Guizhou Province from 2012 to 2015]

Objective: To analyze the genetic characteristics of rubella virus isolated from 2012 to 2015 in Guizhou province. Methods: A total of 390 cases of suspected measles were collected from Guizhou measles network laboratory from 2012 to 2015 and 25 cases of rubella cases were diagnosed. Rubella virus isolation was performed using Vero/SLAM cells. The presence of rubella viral RNA was detected using Real-time RT-PCR after RNA extraction from infected tissue culture cells. Fragments of 480 bp and 633 bp nucleotides of E1 genes of the isolates were amplified by RT-PCR and the PCR products were sequenced and spliced. The phylogenetic tree was conducted based on the 739 bp nucleotide sequences of E1 genes and gene characteristic analysis was performed. Results: There were 19 cases of rubella outbreaks and 6 cases of rubella sporadic cases in 25 cases of suspected rubella cases. There were 11 males (44.0%) and 14 females (56.0%). The mean age and standard deviation were (12.3±3.9) years. A total of 10 rubella strains were isolated. The results of phylogenetic analysis showed that 7 strains of rubella virus isolates belonged to genotype 1E and the other belonged to genotype 2B. The nucleotide acid and amino acid homology among 7 strains 1E genotype were 99.0%-100% and 100% respectively. 2B genotype of 3 strains of nucleotide and amino acid homology were 99.4%-100% and 99.5%-100% respectively. Ten strains of rubella virus were not mutated in the E1 glycoprotein gene, Asn 177 and Asn 209 N-type glycosylation sites and E1 antigen epitopes between 213 and 285aa.Among them, 7 strains of 1E genotype had a mutation from leucine to phenylalanine in 338 amino acid, 2 strains of 2B genotype at 377 amino acids from valine to alanine. Conclusion: Rubella virus epidemic was caused by 1E and 2B genotypes in Guizhou from 2012 to 2015.Ten strains of rubella virus were highly conserved in nucleotide and amino acid sequences and there was no variation of important functional sites.

Ultrasound hyperthermia induces apoptosis in head and neck squamous cell carcinoma: An in vitro study

Background

Hyperthermia is considered an efficient complement in the treatment of head and neck squamous cell carcinoma (HNSCC). Hyperthermia induces cell apoptosis in a temperature- and time-dependent manner. However, the molecular mechanism of hyperthermia remains unclear. The aim of this study was to investigate the mechanism of apoptosis induced by ultrasound hyperthermia in HNSCC cell lines HN-30 and HN-13.

Material and Methods

We examined the dynamic changes of early apoptosis and secondary necrosis in HN-30 and HN-13 cells treated by hyperthermia at 42°C for 10 min. We further examined mitochondrial membrane potential in vitro by ultrasound hyperthermia for different heating temperatures (38-44°C, 10 min) and heating times (42°C, 10-50 min). After heating by ultrasound at 42°C for 10 min, the apoptosis index achieved its highest level at 8 h after treatment, decreased rapidly and remained constant at a reduced level at 12 h.

Results

The level of secondary necrosis increased with the level of early apoptosis but remained at a higher level until 14 h. The level of secondary necrosis correlated with the level of early apoptosis (HN-13: r=0.7523, P=0.0030; HN-30: r=0.6510, P=0.016). The fractions of cells with low mitochondrial membrane potential (Δψ) in the heating-temperature grads group and heating-time grads group decreased significantly over time. Therefore, HN-30 and HN-13 cells developed apoptosis after ultrasound hyperthermia treatment with decreases in the mitochondrial transmembrane potential level.

Conclusions

Ultrasound hyperthermia induces apoptosis in HN-30 and HN-13 cells, possibly via the mitochondrial caspase pathway.

Key words:Head and neck squamous cell carcinoma, apoptosis, mitochondrial membrane potential, ultrasound hyperthermia.

Neutron Generation by Laser-Driven Spherically Convergent Plasma Fusion

We investigate a new laser-driven spherically convergent plasma fusion scheme (SCPF) that can produce thermonuclear neutrons stably and efficiently. In the SCPF scheme, laser beams of nanosecond pulse duration and 10^{14}-10^{15}  W/cm^{2} intensity uniformly irradiate the fuel layer lined inside a spherical hohlraum. The fuel layer is ablated and heated to expand inwards. Eventually, the hot fuel plasmas converge, collide, merge, and stagnate at the central region, converting most of their kinetic energy to internal energy, forming a thermonuclear fusion fireball. With the assumptions of steady ablation and adiabatic expansion, we theoretically predict the neutron yield Y_{n} to be related to the laser energy E_{L}, the hohlraum radius R_{h}, and the pulse duration τ through a scaling law of Y_{n}∝(E_{L}/R_{h}^{1.2}τ^{0.2})^{2.5}. We have done experiments at the ShengGuangIII-prototype facility to demonstrate the principle of the SCPF scheme. Some important implications are discussed.

Development of a vaccine against Streptococcus agalactiae in fish based on truncated cell wall surface anchor proteins

Streptococcus agalactiae is an important fish pathogen and a leading cause of major economic losses to the aquaculture industry worldwide. In the present study, the two truncated recombinant proteins of cell wall surface anchor family of S agalactiae, CWSAP465 and CWSAP1035, were expressed in Escherichia coli, and their immunogenicity and efficacy against the bacterium were evaluated in tilapia and turbot. The results showed that the prokaryotic expression of the two constructs, p32a-CWSAP465 and p32a-CWSAP1035, gave rise to a high yield of soluble proteins with good immunogenicity. The immunisation-challenge study revealed that tilapia and turbot immunised with recombinant truncated proteins produced high levels of antibodies with a peak at four weeks after immunisation and were protected from a challenge by a virulent S agalactiae at a dose of 1×10⁹ colony forming units/ml. The recombinant truncated proteins had higher efficacy than the whole-cell inactivated vaccine. Therefore, the study demonstrated that CWSAP465 and CWSAP1035 are two viable vaccine candidates against S agalactiae in fish.

[Head and neck alveolar soft-part sarcoma: a review in diagnosis and treatment]

Head and neck alveolar soft part sarcoma(ASPS) is a rare, distinctive sarcoma, typically occurring in infants and children.It displays a relatively fast clinical course, and the ultimate prognosis is poor and is often characterised by late metastases. It is now clear that they are caused by the formation of an ASPL TFE3 fusion gene,and the new molecular target therapies under study may change the possible approach to primary disease.The diagnosis and treatment of head and neck ASPS are reviewed in this article.

Lubricin/Proteoglycan 4 binds to and regulates the activity of Toll-Like Receptors In Vitro

Proteoglycan 4 (PRG4/lubricin) is secreted by cells that reside in articular cartilage and line the synovial joint. Lubricin may play a role in modulating inflammatory responses through interaction with CD44. This led us to examine if lubricin could be playing a larger role in the modulation of inflammation/immunity through interaction with Toll-like receptors (TLRs). Human Embryonic Kidney (HEK) cells overexpressing TLRs 2, 4 or 5 and surface plasmon resonance were employed to determine if full length recombinant human lubricin was able to bind to and activate TLRs. Primary human synovial fibroblasts were also examined using flow cytometry and Luminex multiplex ELISA. A rat destabilization model of osteoarthritis (OA) was used to determine if lubricin injections were able to regulate pain and/or inflammation in vivo. Lubricin can bind to and regulate the activity of TLRs, leading to downstream changes in inflammatory signalling independent of HA. We confirmed these findings in vivo through intra-articular injections of lubricin in a rat OA model where the inhibition of systemic inflammatory signaling and reduction in pain were observed. Lubricin plays an important role in regulating the inflammatory environment under both homeostatic and tissue injury states.

Interferon-α-2b as an adjuvant therapy prolongs survival of patients with previously resected oral muscosal melanoma

Two major subtypes of melanoma include cutaneous melanoma and mucosal melanoma. The latter type is rare and usually occurs in the head and neck region. High-dose interferon-α-2b (IFN-α-2b) has proven effective in the treatment of cutaneous melanoma. Recently, a regimen of temozolomide plus cisplatin was reported more likely to improve relapse-free survival and overall survival than high-dose IFN-α-2b for mucosal melanoma. We conducted this study to analyze the therapeutic effect of high-dose IFN-α-2b for patients with oral mucosal melanoma who had received prior chemotherapy. One hundred and seventeen patients with stage III-IVa oral mucosal melanoma who had received chemotherapy were analyzed. The overall survival and relapse-free survival were compared between the patients with/without high-dose IFN-α-2b. The results indicate that the IFN-α-2b treatment group had a longer relapse-free survival rate (P = 0.0169) as compared to the control group. However, the overall survival was not significant between the two groups (P = 0.096), except in patients in stage IVa, whose overall survival increased by 20 months (P = 0.0146). The adverse reactions included a drug-induced influenza-like syndrome, gastrointestinal responses, myelosuppression, and hepatoxicity, which were predominantly of grade 1-2 and reversible. Thus, patients with resected oral mucosal melanoma, even those who have received chemotherapy, could benefit from the treatment of high-dose IFN-α-2b.

Comparison of PEGylated FGF-21 with insulin glargine for long-lasting hypoglycaemic effect in db/db mice

AIM

This study investigated the long-acting antidiabetic efficacy of PEGylated fibroblast growth factor (FGF)-21 in type 2 diabetic db/db mice.

METHODS

PEGylated FGF-21 was prepared by modifying the N-terminus of human FGF-21 (hFGF-21) using mPEG-ALD. To compare the long-lasting hypoglycaemic effects of PEGylated FGF-21 and insulin glargine in diabetic db/db mice, their pharmacological efficacy was evaluated by changes in blood glucose levels, body weight, insulin levels, glycosylated haemoglobin levels, lipid profile and liver function parameters, and by oral glucose tolerance tests (OGTTs).

RESULTS

Both PEGylated FGF-21 and insulin glargine decreased plasma glucose in db/db mice. However, compared with insulin glargine treatment, PEGylated FGF-21 therapy had more significant effects in lowering blood glucose and glycosylated haemoglobin levels, improving lipid profile and liver function parameters, alleviating insulin resistance and reducing the glucose area under the curve in OGTTs.

CONCLUSION

Our results suggest that PEGylated FGF-21 is an ideal candidate as a long-acting antidiabetes drug, and holds significant promise as an effective therapeutic agent in the treatment of type 2 diabetes patients.

Polymorphism in the 5ꞌ-UTR of the insulin-like growth factor I gene associated with production traits in Chinese cattle

The insulin-like growth factor I (IGF-1) gene plays important roles in the growth and body composition of animals. Serum IGF1 concentration has been associated with growth traits in many livestock species. We found a polymorphism of cattle IGF1-TasI locus and analyzed the distribution of alleles in three cattle breeds, including Qinchuan, Nanyang, and Chinese Holstein. PCR-RFLP analysis showed that allele A was the dominant allele. The frequencies of allele A varied from 0.84 to 0.97. Distributions of genotypic and allelic frequencies were significantly different among breeds. Polymorphism of the IGF1 gene was significantly affecting hucklebone width at 6 months in the Nanyang breed and protein and fat yield of the third lactation in Chinese Holstein cattle. Individuals with allele C had a significantly higher performance in production traits.

Molecular characterization and expression pattern of an α-amylase gene (HcAmy) from the freshwater pearl mussel, Hyriopsis cumingii

The freshwater pearl mussel Hyriopsis cumingii is of commercial importance because it produces the freshwater pearl; however, knowledge about the molecular characterization and regulation mechanisms of α-amylase remains unknown for this species. In this study, the full-length cDNA of the α-amylase gene (HcAmy) was isolated from H. cumingii by the rapid amplification of cDNA ends. Tissue-specific expression analysis showed that HcAmy mRNA was mainly expressed in the hepatopancreas; although, the gene was also expressed in the adductor muscle, intestine, gill, and crystalline style. After 2 weeks starvation, the expression of HcAmy mRNA in the hepatopancreas was upregulated at 24 h after re-feeding or when exposed to algal concentration of 32 μg/L chlorophyll-a, indicating that the HcAmy mRNA expression in H. cumingii is regulated by algal availability. The results of this study confirm that the HcAmy gene is an important component of the carbohydrate metabolism of H. cumingii fed phytoplankton. In addition, this study demonstrates that the modulation of this gene is dependent on environmental food availability, including starvation, re-feeding time following a period of starvation, and algal concentrations during re-feeding.

Phylogenetic distinction of iNOS and IDO function in mesenchymal stem cell-mediated immunosuppression in mammalian species

Mammalian mesenchymal stem cells (MSCs) have been shown to be strongly immunosuppressive in both animal disease models and human clinical trials. We have reported that the key molecule mediating immunosuppression by MSCs is species dependent: indoleamine 2,3-dioxygenase (IDO) in human and inducible nitric oxide synthase (iNOS) in mouse. In the present study, we isolated MSCs from several mammalian species, each of a different genus, and investigated the involvement of IDO and iNOS during MSC-mediated immunosuppression. The characterization of MSCs from different species was by adherence to tissue culture plastic, morphology, specific marker expression, and differentiation potential. On the basis of the inducibility of IDO and iNOS by inflammatory cytokines in MSCs, the tested mammalian species fall into two distinct groups: IDO utilizers and iNOS utilizers. MSCs from monkey, pig, and human employ IDO to suppress immune responses, whereas MSCs from mouse, rat, rabbit, and hamster utilize iNOS. Interestingly, based on the limited number of species tested, the iNOS-utilizing species all belong to the phylogenetic clade, Glires. Although the evolutionary significance of this divergence is not known, we believe that this study provides critical guidance for choosing appropriate animal models for preclinical studies of MSCs.

Lack of genotoxicity due to foamy virus vector integration in human iPSCs

Integrating vectors can lead to the dysregulation of nearby chromosomal genes, with important consequences for clinical trials and cellular engineering. This includes the retroviral and lentiviral vectors commonly used for deriving induced pluripotent stem cells (iPSCs). We previously used integrating foamy virus (FV) vectors expressing OCT4, SOX2, MYC, and KLF4 to reprogram osteogenesis imperfecta mesenchymal stem cells (MSCs). Here we have studied the effects of 10 FV vector proviruses on neighboring gene expression in four iPSC lines and their corresponding iPSC-derived mesenchymal stem cells (iMSCs). Gene expression profiles in these iPSC lines showed that none of the 38 genes within 300 kb up- or downstream of integrated proviruses had a significant difference in mRNA levels, including 5 genes with proviruses in their transcription units. In the iMSCs derived from these iPSCs, the same type of analysis showed a single dysregulated transcript out of 46 genes found near proviruses. This frequency of dysregulation was similar to that of genes lacking nearby proviruses, so it may have been due to interclonal variation and/or measurement inaccuracies. While the number of integration sites examined in this paper is limited, our results suggest that integrated FV proviruses do not impact the expression of chromosomal genes in pluripotent human stem cells or their differentiated derivatives. This interpretation is consistent with previous reports that FV vectors have minimal genotoxicity, even when integrating near or within genes.

Mesenchymal stem cells: a double-edged sword in regulating immune responses

Mesenchymal stem cells (MSCs) have been employed successfully to treat various immune disorders in animal models and clinical settings. Our previous studies have shown that MSCs can become highly immunosuppressive upon stimulation by inflammatory cytokines, an effect exerted through the concerted action of chemokines and nitric oxide (NO). Here, we show that MSCs can also enhance immune responses. This immune-promoting effect occurred when proinflammatory cytokines were inadequate to elicit sufficient NO production. When inducible nitric oxide synthase (iNOS) production was inhibited or genetically ablated, MSCs strongly enhance T-cell proliferation in vitro and the delayed-type hypersensitivity response in vivo. Furthermore, iNOS^−/− MSCs significantly inhibited melanoma growth. It is likely that in the absence of NO, chemokines act to promote immune responses. Indeed, in CCR5^−/−CXCR3^−/− mice, the immune-promoting effect of iNOS^−/− MSCs is greatly diminished. Thus, NO acts as a switch in MSC-mediated immunomodulation. More importantly, the dual effect on immune reactions was also observed in human MSCs, in which indoleamine 2,3-dioxygenase (IDO) acts as a switch. This study provides novel information about the pathophysiological roles of MSCs.