Catechins as a Potential Dietary Supplementation in Prevention of Comorbidities Linked with Down Syndrome.

Plant-derived polyphenols flavonoids are increasingly being recognized for their medicinal potential. These bioactive compounds derived from plants are gaining more interest in ameliorating adverse health risks because of their low toxicity and few side effects. Among them, therapeutic approaches demonstrated the efficacy of catechins, a major group of flavonoids, in reverting several aspects of Down syndrome, the most common genomic disorder that causes intellectual disability. Down syndrome is characterized by increased incidence of developing Alzheimer's disease, obesity, and subsequent metabolic disorders. In this focused review, we examine the main effects of catechins on comorbidities linked with Down syndrome. We also provide evidence of catechin effects on DYRK1A, a dosage-sensitive gene encoding a protein kinase involved in brain defects and metabolic disease associated with Down syndrome.

Long non-coding RNA LINC01123 promotes cell proliferation, migration and invasion via interacting with SRSF7 in colorectal cancer.

BACKGROUND: Increasing evidences demonstrated that long non-coding RNAs (lncRNAs) participates in the occurrence and development of cancer. In this study, we explored the function and molecular mechanism of LINC01123 in colorectal cancer progression. METHODS: Analyze the expression level of LINC01123 in gastrointestinal tumors via TCGA database. Colorectal tumor tissues and normal tissues were collected to detect the expression of LINC01123 by RT-qPCR. CCK-8 assay, clone formation assay, transwell assay, and wound healing assays were used to explore the effects of LINC01123 on the proliferation, invasion and migration of colorectal cancer cells. Coomassie blue staining, RNA pull-down and mass spectrometry were used to screen the protein interacted with LINC01123. Xenograft model was used to explore the effect of LINC01123 in vivo. RESULTS: LINC01123 was up-regulated in colorectal cancer tumor tissues. The proliferation, invasion and migration ability of colorectal cancer cells were decreased significantly after LINC01123 knockdown, and it may inhibit its expression by interacted with SRSF7, thereby promoting colorectal cancer progression. CONCLUSIONS: LINC01123 can promote the proliferation, invasion and migration of colorectal cancer cells by regulating SRSF7, suggesting that it may be an important regulator of colorectal cancer progression.

Cytokine/Chemokine Expression Is Closely Associated Disease Severity of Human Adenovirus Infections in Immunocompetent Adults and Predicts Disease Progression.

Increasing human Adenovirus (HAdV) infections complicated with acute respiratory distress syndrome (ARDS) even fatal outcome were reported in immunocompetent adolescent and adult patients. Here, we characterized the cytokine/chemokine expression profiles of immunocompetent patients complicated with ARDS during HAdV infection and identified biomarkers for disease severity/progression. Forty-eight cytokines/chemokines in the plasma samples from 19 HAdV-infected immunocompetent adolescent and adult patients (ten complicated with ARDS) were measured and analyzed in combination with clinical indices. Immunocompetent patients with ARDS caused by severe acute respiratory disease coronavirus (SARS-CoV)-2, 2009 pandemic H1N1 (panH1N1) or bacteria were included for comparative analyses. Similar indices of disease course/progression were found in immunocompetent patients with ARDS caused by HAdV, SARS-CoV-2 or panH1N infections, whereas the HAdV-infected group showed a higher prevalence of viremia, as well as increased levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT) and creatine kinase (CK). Expression levels of 33 cytokines/chemokines were increased significantly in HAdV-infected patients with ARDS compared with that in healthy controls, and many of them were also significantly higher than those in SARS-CoV-2-infected and panH1N1-infected patients. Expression of interferon (IFN)-γ, interleukin (IL)-1ß, hepatocyte growth factor (HGF), monokine induced by IFN-γ (MIG), IL-6, macrophage-colony stimulating factor (M-CSF), IL-10, IL-1α and IL-2Ra was significantly higher in HAdV-infected patients with ARDS than that in those without ARDS, and negatively associated with the ratio of the partial pressure of oxygen in arterial blood/fraction of inspired oxygen (PaO2/FiO2). Analyses of the receiver operating characteristic curve (ROC) showed that expression of IL-10, M-CSF, MIG, HGF, IL-1ß, IFN-γ and IL-2Ra could predict the progression of HAdV infection, with the highest area under the curve (AUC) of 0.944 obtained for IL-10. Of note, the AUC value for the combination of IL-10, IFN-γ, and M-CSF reached 1. In conclusion, the "cytokine storm" occurred during HAdV infection in immunocompetent patients, and expression of IL-10, M-CSF, MIG, HGF, IL-1ß, IFN-γ and IL-2Ra was closely associated with disease severity and could predict disease progression.

[Long non-coding RNA LINC01106 regulates colorectal cancer cell proliferation and apoptosis through the STAT3 pathway].

OBJECTIVE: To investigate the expression of LINC01106 in colorectal cancer and its role in regulating the proliferation and apoptosis of colorectal cancer cells. METHODS: We analyzed the data of LINC01106 expression levels in tumor tissues and normal tissues of patients with colorectal cancer in TCGA database and explored the association of LINC01106 expression level with the prognosis of the patients. Colorectal cancer SW480 cell lines with LINC01106 knockdown or overexpression were established, and their proliferation and apoptosis relative to the parental cells were evaluated using CCK-8 assay and flow cytometry, respectively. The expressions of p-STAT3, STAT3, and Bcl-2 in the cells were detected by immunoblotting. Nude mouse models bearing xenografts of SW480 cells with LINC01106 knockdown or na?ve SW480 cells were established to observe the effect of LINC01106 knockdown on the growth of SW480 cells in vivo. RESULTS: Analysis of the data from TCGA database showed that the expression level of LINC01106 was significantly higher in colorectal cancer tissues than in normal tissues, and LINC01106 expression level was significantly related to the prognosis of the patients (P < 0.05). Knockdown of LINC01106 significantly inhibited the proliferation and promoted apoptosis of SW480 cells (P < 0.05), while LINC01106 overexpression significantly promoted proliferation of the cells. LINC01106 knockdown in SW-480 cells obviously lowered the expressions of p- STAT3 and Bcl-2 and suppressed the growth of the xenograft in nude mice. CONCLUSIONS: LINC01106 is significantly up-regulated in colorectal cancer tissue and is related to the prognosis of the patients. LINC01106 can regulate the proliferation and apoptosis of SW480 cells through STAT3/Bcl-2 signaling and may serve as a potential marker for the diagnosis and prognostic evaluation of colorectal cancer.

Overview of the STAT-3 signaling pathway in cancer and the development of specific inhibitors.

Signal transducer and activator of transcription (STAT) proteins represent novel therapeutic targets for the treatment of cancer. In particular, STAT-3 serves critical roles in several cellular processes, including the cell cycle, cell proliferation, cellular apoptosis and tumorigenesis. Persistent activation of STAT-3 has been reported in a variety of cancer types, and a poor prognosis of cancer may be associated with the phosphorylation level of STAT-3. Furthermore, elevated STAT-3 activity has been demonstrated in a variety of mammalian cancers, both in vitro and in vivo. This indicates that STAT-3 serves an important role in the progression of numerous cancer types. A significant obstacle in developing STAT-3 inhibitors is the demonstration of the antitumor efficacy in in vivo systems and the lack of animal models for human tumors. Therefore, it is crucial to determine whether available STAT-3 inhibitors are suitable for clinical trials. Moreover, further preclinical studies are necessary to focus on the impact of STAT-3 inhibitors on tumor cells. When considering STAT-3 hyper-activation in human cancer, selective targeting to these proteins holds promise for significant advancement in cancer treatment. In the present study, advances in our knowledge of the structure of STAT-3 protein and its regulatory mechanisms are summarized. Moreover, the STAT-3 signaling pathway and its critical role in malignancy are discussed, in addition to the development of STAT-3 inhibitors in various cancer types.

Molecular Rescue of Dyrk1A Overexpression Alterations in Mice with Fontup® Dietary Supplement: Role of Green Tea Catechins.

Epigallocatechin gallate (EGCG) is an inhibitor of DYRK1A, a serine/threonine kinase considered to be a major contributor of cognitive dysfunctions in Down syndrome (DS). Two clinical trials in adult patients with DS have shown the safety and efficacy to improve cognitive phenotypes using commercial green tea extract containing EGCG (45% content). In the present study, we performed a preclinical study using FontUp®, a new nutritional supplement with a chocolate taste specifically formulated for the nutritional needs of patients with DS and enriched with a standardized amount of EGCG in young mice overexpressing Dyrk1A (TgBACDyrk1A). This preparation is differential with previous one used, because its green tea extract has been purified to up 94% EGCG of total catechins. We analyzed the in vitro effect of green tea catechins not only for EGCG, but for others residually contained in FontUp®, on DYRK1A kinase activity. Like EGCG, epicatechin gallate was a noncompetitive inhibitor against ATP, molecular docking computations confirming these results. Oral FontUp® normalized brain and plasma biomarkers deregulated in TgBACDyrk1A, without negative effect on liver and cardiac functions. We compared the bioavailability of EGCG in plasma and brain of mice and have demonstrated that EGCG had well crossed the blood-brain barrier.

Small molecule STAT3 inhibitor, 6Br-6a suppresses breast cancer growth in vitro and in vivo.

Signal transducer and activator of transcription 3 (STAT3) protein frequently overexpressed in many malignancies and plays an essential role in regulating proliferation, apoptosis, migration and invasion in cancer cells. However, No STAT3 inhibitor was used clinically. In this study, we evaluated the toxic potential of a novel STAT3 inhibitor, 6Br-6a in breast cancer cell lines. The anti-cancer effect and underlying mechanism of 6Br-6a on MDA-MB-231 and MCF-7 cells were determined in vitro and in xenograft mouse model. Our data demonstrated that 6Br-6a significantly induced cell cycle arrest and cell apoptosis in breast cancer via blocking the activation of STAT3. Finally, we verified these inhibitory effects of 6Br-6a in the MDA-MB-231 xenograft mouse model. In conclusion, 6Br-6a effectively inhibited activation of STAT3 and induced cell cycle arrest and apoptosis via regulating cyclin D1 and Bcl-2 expression. All of these data indicate that 6Br-6a could be a potential candidate for the treatment of breast cancer.

High expression of apoptosis protein (Api-5) in chemoresistant triple-negative breast cancers: an innovative target.

Anti-apoptotic protein-5 (API-5) is a survival protein interacting with the protein acinus, preventing its cleavage by caspase-3 and thus inhibiting apoptosis. We studied the effect of targeting API-5 in chemoresistant triple negative breast cancers (TNBCs), to reverse chemoresistance. 78 TNBC biopsies from patients with different responses to chemotherapy were analysed for API-5 expression before any treatment. Further studies on API-5 expression and inhibition were performed on patient-derived TNBC xenografts, one highly sensitive to chemotherapies (XBC-S) and the other resistant to most tested drugs (XBC-R). In situ assessments of necrosis, cell proliferation, angiogenesis, and apoptosis in response to anti-API-5 peptide were performed on the TNBC xenografts. Clinical analyses of the 78 TNBC biopsies revealed that API-5 was more markedly expressed in endothelial cells before any treatment among patients with chemoresistant TNBC, and this was associated with greater micro-vessel density. A transcriptomic analysis of xenografted tumors showed an involvement of anti-apoptotic genes in the XBC-R model, and API-5 expression was higher in XBC-R endothelial cells. API-5 expression was also correlated with hypoxic stress conditions both in vitro and in vivo. 28 days of anti-API-5 peptide efficiently inhibited the XBC-R xenograft via caspase-3 apoptosis. This inhibition was associated with major inhibition of angiogenesis associated with necrosis and apoptosis. API-5 protein could be a valid therapeutic target in chemoresistant metastatic TNBC.

Hypothesis and Theory: Circulating Alzheimer's-Related Biomarkers in Type 2 Diabetes. Insight From the Goto-Kakizaki Rat.

Epidemiological data suggest an increased risk of developing Alzheimer's disease (AD) in individuals with type 2 diabetes (T2D). AD is anatomically associated with an early progressive accumulation of Aß leading to a gradual Tau hyperphosphorylation, which constitute the main characteristics of damaged brain in AD. Apart from these processes, mounting evidence suggests that specific features of diabetes, namely impaired glucose metabolism and insulin signaling in the brain, play a key role in AD. Moreover, several studies report a potential role of Aß and Tau in peripheral tissues such as pancreatic ß cells. Thus, it appears that several biological pathways associated with diabetes overlap with AD. The link between peripheral insulin resistance and brain insulin resistance with concomitant cognitive impairment may also potentially be mediated by a liver/pancreatic/brain axis, through the excessive trafficking of neurotoxic molecules across the blood-brain barrier. Insulin resistance incites inflammation and pro-inflammatory cytokine activation modulates the homocysteine cycle in T2D patients. Elevated plasma homocysteine level is a risk factor for AD pathology and is also closely associated with metabolic syndrome. We previously demonstrated a strong association between homocysteine metabolism and insulin via cystathionine beta synthase (CBS) activity, the enzyme implicated in the first step of the trans-sulfuration pathway, in Goto-Kakizaki (GK) rats, a spontaneous model of T2D, with close similarities with human T2D. CBS activity is also correlated with DYRK1A, a serine/threonine kinase regulating brain-derived neurotrophic factor (BDNF) levels, and Tau phosphorylation, which are implicated in a wide range of disease such as T2D and AD. We hypothesized that DYRK1A, BDNF, and Tau, could be among molecular factors linking T2D to AD. In this focused review, we briefly examine the main mechanisms linking AD to T2D and provide the first evidence that certain circulating AD biomarkers are found in diabetic GK rats. We propose that the spontaneous model of T2D in GK rat could be a suitable model to investigate molecular mechanisms linking T2D to AD.

MiR-146a-5p inhibits cell proliferation and cell cycle progression in NSCLC cell lines by targeting CCND1 and CCND2.

Previous studies have indicated that miR-146a-5p acts as an oncogene in several types of cancer, yet a tumor suppressor gene in others. In non-small cell lung cancer (NSCLC), one report showed that it was downregulated and played the role of tumor suppressor. However, another study showed that miR-146a-5p was overexpressed in the serum of NSCLC patients compared to healthy controls. Therefore, it is obvious that further study of the function of miR-146a-5p in NSCLC is necessary to fully understand its importance. Herein, we have verified that miR- 146a- 5p acts as a tumor suppressor in NSCLC. Our data revealed that the expression level of miR-146a-5p was significantly decreased in several human NSCLC cell lines, and also less abundant in human NSCLC tissues, when compared with controls. Moreover, we observed that miR-146a-5p could suppress cell proliferation, both in vitro and in vivo. Our results also showed that miR-146a-5p directly targeted the 3'-UTR of CCND1 and CCND2 mRNAs as well as decreased their expression at both mRNA and protein levels, causing cell cycle arrest at the G0/G1 phase. Furthermore, siRNA-mediated downregulation of CCND1 or CCND2 yielded the same effects on proliferation and cell cycle arrest as miR-146a-5p upregulation did in the NSCLC cell lines. We confirmed that the expression of miR-146a-5p had negative relationship with CCND1 or CCND2. Besides, we also found that miR-146a-5p could inhibit tumor growth in xengroft mouse models, and CCND1 and CCND2 were downregulated in miR-146a-5p overexpressed xengroft tumor tissues. In summary, our results demonstrated that miR-146a-5p could suppress the proliferation and cell cycle progression in NSCLC cells by inhibiting the expression of CCND1 and CCND2.

[Resistance to anti-angiogenic therapy: a clinical and scientific current issue]. / La résistance aux traitements antiangiogéniques - Une actualité clinique et scientifique.

Although the use of anti-angiogenic agents has been considered a promising strategy to block tumor growth and improve the bioavailability of drugs into the tumor, the use of most of them in clinical trials is limited. The development of resistance to some anti-angiogenic agents and their high toxicity are currently under investigations. However, the approach is still valid since this therapeutic tool has lengthened survival of patients with colon, breast, kidney, lungs and liver cancers. The identification of biomarkers in response to this family of drugs is an important area of investigation.

Molecular rescue of DYRK1A overexpression in cystathionine beta synthase-deficient mouse brain by enriched environment combined with voluntary exercise.

Hyperhomocysteinemia resulting from cystathionine beta synthase (CBS) deficiency can produce cognitive dysfunction. We recently found that CBS-deficient mice exhibit increased expression of the serine/threonine kinase dual-specificity tyrosine-(Y)-phosphorylation-regulated kinase 1A (DYRK1A) in the brain. When dysregulated, DYRK1A contributes to the neurodegeneration, neuronal death, and loss of function observed in neurodegenerative diseases. However, brain plasticity can be improved by interventions like enriched environment combined with voluntary exercise (EE/VE). The present study sought to assess the effects of EE/VE on molecular mechanisms linked to DYRK1A overexpression in the brain of CBS-deficient mice. EE/VE was applied to 3-month-old female CBS-deficient mice for 1 month. Without intervention, CBS-deficient mice exhibited increased DYRK1A and decreased brain-derived neurotrophic factor (BDNF) levels in the cortex and hippocampus. However, EE/VE rescued these altered DYRK1A and BDNF levels in the hippocampus of CBS-deficient mice. We conclude that exercise combined with enriched environment can restore the altered molecular mechanisms in the brain of CBS-deficient mice.

[Total flavonoids of litsea coreana decreases the cytotoxicity of oxaliplatin in TM3 Leydig cells via enhancing the function of gap junction].

OBJECTIVE: To investigate the effects of total flavonoids of Litsea Coreana (TFLC) on the gap junction (GJ) intercellular communication in TM3 testicular Leydig cells and whether TFLC can reduce the cytotoxicity of oxaliplatin (OHP) in vitro. METHODS: We detected the effect of TFLC on the dye spread of the in vitro cultured TM3 cells by parachute assay, observed changes in the expression of connexin 43 (Cx43) total protein in the TFLC-treated TM3 cells by Western blot, and determined the effects of TFLC on the expression of Cx43 on the membrane of the TM3 cells by immunofluorescence assay and on the cytotoxicity of OHP by MTT assay. RESULTS: TFLC obviously enhanced the GJ function with the increasing of the TFLC concentration in the TM3 cells. Western blot and immunofluorescence assay confirmed that TFLC significantly enhanced the expression of Cx43 total protein and Cx43 expression on the membrane of the TM3 cells. MTT assay showed that at a high cell density (confluent with GJ formation), 20 microg/ml TFLC enhanced the GJ function of the TM3 cells and reduced the cytotoxicity of OHP (P < 0.05), while at a low density (preconfluent with no GJ formation), TFLC exhibited no effect on the cytotoxicity of OHP (P > 0.05). CONCLUSION: TFLC increases the Cx43 expression and GJ function in normal TM3 Leydig cells, and the enhancement of GJ function reduces the cytotoxicity of OHP.

LC-MS/MS coupled with QSAR modeling in characterising of angiotensin I-converting enzyme inhibitory peptides from soybean proteins.

The importance of soy products in reducing the risk of cardiovascular disease is well documented. Our previous computation study has indicated the presence of several potent ACE inhibitory peptides within soybean proteins which needs to be identified. The aim of the study was to identify ACE inhibitory peptides from soy proteins using LC-MS/MS coupled with quantitative structure-activity relationship (QSAR) model. Soybean protein hydrolysate digested by thermolysin showed an IC50 value of 53.6 µg/mL, decreased slightly to 51.8 µg/mL after adding pepsin, and increased to 115.6 µg/mL after adding trypsin. A total of 34 peptides were characterised from LC-MS/MS. Five novel tripeptides, IVF, LLF, LNF, LSW and LEF, with predicted IC50 values lower than 10 µM were synthesized and validated. The results showed that soybean is an excellent source of ACE inhibitory peptides.

Haploidentical in utero hematopoietic cell transplantation improves phenotype and can induce tolerance for postnatal same-donor transplants in the canine leukocyte adhesion deficiency model.

In the murine model, in utero hematopoietic cell transplantation (IUHCT) has been shown to achieve low levels of allogeneic chimerism and associated donor-specific tolerance permitting minimal conditioning postnatal hematopoietic stem cell transplantation (HSCT). In this pilot study, we investigated IUHCT in the canine leukocyte adhesion deficiency (CLAD) model. Haploidentical IUHCT resulted in stable low-level donor cell chimerism in all dogs that could be analyzed by sensitive detection methodology (4 of 10) through 18 months of follow-up. In the 2 CLAD recipients, low-level chimerism resulted in amelioration and complete reversal of the CLAD phenotype, respectively. Six recipients of IUHCT (5 carriers and 1 CLAD) subsequently received postnatal HSCT from the same haploidentical prenatal donor after minimal conditioning with busulfan 10 mg/kg. Chimerism in 2 of 5 CLAD carriers that underwent HSCT increased from < 1% pre-HSCT to sustained levels of 35% to 45%. Control animals undergoing postnatal haploidentical HSCT without IUHCT had no detectable donor chimerism. These results demonstrate that haploidentical IUHCT in the CLAD model can result in low-level donor chimerism that can prevent the lethal phenotype in CLAD dogs, and can result in donor-specific tolerance that can facilitate postnatal minimal conditioning HSCT.

Human cord blood stem cell applications in cell therapy.

Human umbilical cord blood (UCB) is a valuable alternative source of ethically acceptable, clinically competent stem cells that is most likely closest to embryonic stem cells. Development of reliable methods for the expansion of cord blood stem cells is critical to ensure their clinical application. In the present article, advances in cord blood stem cell isolation, culture expansion methods through co-culture with human mesenchymal stem cells, culture optimization techniques with defined media and cord blood stem cell banking aspects have been reviewed. Refined methods of isolation as well as defined culture conditions of expansion that favor retention of stem cell phenotype and proper cryogenic storage can significantly increase the use of cord blood stem cells in human cell therapy applications.

Successful treatment of canine leukocyte adhesion deficiency by foamy virus vectors.

Recent successes in treating genetic immunodeficiencies have demonstrated the therapeutic potential of stem cell gene therapy. However, the use of gammaretroviral vectors in these trials led to insertional activation of nearby oncogenes and leukemias in some study subjects, prompting studies of modified or alternative vector systems. Here we describe the use of foamy virus vectors to treat canine leukocyte adhesion deficiency (CLAD). Four of five dogs with CLAD that received nonmyeloablative conditioning and infusion of autologous, CD34+ hematopoietic stem cells transduced by a foamy virus vector expressing canine CD18 had complete reversal of the CLAD phenotype, which was sustained more than 2 years after infusion. In vitro assays showed correction of the lymphocyte proliferation and neutrophil adhesion defects that characterize CLAD. There were no genotoxic complications, and integration site analysis showed polyclonality of transduced cells and a decreased risk of integration near oncogenes as compared to gammaretroviral vectors. These results represent the first successful use of a foamy virus vector to treat a genetic disease, to our knowledge, and suggest that foamy virus vectors will be effective in treating human hematopoietic diseases.

Correction of the disease phenotype in canine leukocyte adhesion deficiency using ex vivo hematopoietic stem cell gene therapy.

Canine leukocyte adhesion deficiency (CLAD) represents the canine counter-part of the human disease leukocyte adhesion deficiency (LAD). Defects in the leukocyte integrin CD18 adhesion molecule in both CLAD and LAD lead to recurrent, life-threatening bacterial infections. We evaluated ex vivo retroviral-mediated gene therapy in CLAD using 2 nonmyeloablative conditioning regimens--200 cGy total body irradiation (TBI) or 10 mg/kg busulfan--with or without posttransplantation immunosuppression. In 6 of 11 treated CLAD dogs, therapeutic levels of CD18(+) leukocytes were achieved. Conditioning with either TBI or busulfan allowed long-term engraftment, and immunosuppression was not required for efficacy. The percentage of CD18(+) leukocytes in the peripheral blood progressively increased over 6 to 8 months after infusion to levels ranging from 1.26% to 8.37% at 1-year follow-up in the 6 dogs. These levels resulted in reversal or moderation of the severe CLAD phenotype. Linear amplification-mediated polymerase chain reaction assays indicated polyclonality of insertion sites. These results describe ex vivo hematopoietic stem cell gene transfer in a disease-specific, large animal model using 2 clinically applicable conditioning regimens, and they provide support for the use of nonmyeloablative conditioning regimens in preclinical protocols of retroviral-mediated gene transfer for nonmalignant hematopoietic diseases such as LAD.

Nonmyeloablative conditioning with busulfan before matched littermate bone marrow transplantation results in reversal of the disease phenotype in canine leukocyte adhesion deficiency.

Leukocyte adhesion deficiency (LAD)-1, a primary immunodeficiency disease caused by molecular defects in the leukocyte integrin CD18 molecule, is characterized by recurrent, life-threatening bacterial infections. Myeloablative hematopoietic stem cell transplantation is the only curative treatment for LAD-1. Recently, canine LAD (CLAD) has been shown to be a valuable animal model for the preclinical testing of nonmyeloablative transplantation regimens for the treatment of children with LAD-1. To develop new allogeneic transplantation approaches for LAD-1, we assessed a nonmyeloablative conditioning regimen consisting of busulfan as a single agent before matched littermate allogeneic bone marrow transplantation in CLAD. Three CLAD dogs received busulfan 10 mg/kg intravenously before infusion of matched littermate bone marrow, and all dogs received posttransplantation immunosuppression with cyclosporin A and mycophenolate mofetil. Initially, all 3 dogs became mixed chimeras, and levels of donor chimerism sufficient to reverse the CLAD phenotype persisted in 2 animals. The third dog maintained donor microchimerism with an attenuated CLAD phenotype. These 3 dogs have all been followed up for at least 1 year after transplantation. These results indicate that a nonmyeloablative conditioning regimen with chemotherapy alone is capable of generating stable mixed chimerism and reversal of the disease phenotype in CLAD.

Nonmyeloablative hematopoietic stem cell transplantation corrects the disease phenotype in the canine model of leukocyte adhesion deficiency.

OBJECTIVE: The aim of this study was to test a nonmyeloablative hematopoietic stem cell transplant regimen applicable to children with leukocyte adhesion deficiency (LAD) who have a histocompatible sibling donor by using the canine model of LAD, namely canine leukocyte adhesion deficiency or CLAD. METHODS: Thirteen CLAD pups received a hematopoietic stem cell transplant from a dog leukocyte antigen (DLA)-matched littermate donor after pretransplant nonmyeloablative conditioning with 200 cGy total-body irradiation and posttransplant immunosuppression with cyclosporine and mycophenolate mofetil. Donor chimerism following transplant was assessed by flow cytometry for the presence of donor CD18 peripheral blood leukocytes and leukocyte subsets. RESULTS: Eleven of the 13 transplanted animals achieved stable mixed donor chimerism and reversal of the severe CLAD phenotype without graft-vs-host disease. The level of donor chimerism ranged from 3.9 to 95.5% at 1 year following transplant. There was one early death 3 weeks after transplant from thrombocytopenia and hemorrhage, and one dog with donor microchimerism (0.5% CD18+ donor leukocytes) who had attenuation of the CLAD phenotype. CONCLUSION: These results demonstrate that a nonmyeloablative transplant regimen from a DLA-matched littermate donor leads to mixed chimerism and reversal of the severe disease phenotype in dogs with CLAD, and provides support for the use of this approach in children with LAD who possess a histocompatible sibling donor.