Adenoviral vectors can impair adrenocortical steroidogenesis: clinical implications for natural infections and gene therapy

Increased adrenal steroidogenesis and suppressed corticosteroid responsiveness in critical COVID-19

BACKGROUND

The effect of coronavirus disease 2019 (COVID-19) on adrenal endocrine metabolism in critically ill patients remains unclear. This study aimed to investigate the alterations in adrenal steroidogenic activity, elucidate underlying mechanisms, provide in situ histopathological evidence, and examine the clinical implications.

METHODS

The comparative analyses of the adrenal cortices from 24 patients with fatal COVID-19 and 20 matched controls were performed, excluding patients previously treated with glucocorticoids. SARS-CoV-2 and its receptors were identified and pathological alterations were examined. Furthermore, histological examinations, immunohistochemical staining and ultrastructural analyses were performed to assess corticosteroid biosynthesis. The zona glomerulosa (ZG) and zona fasciculata (ZF) were then dissected for proteomic analyses. The biological processes that affected steroidogenesis were analyzed by integrating histological, proteomic, and clinical data. Finally, the immunoreactivity and responsive genes of mineralocorticoid and glucocorticoid receptors in essential tissues were quantitatively measured to evaluate corticosteroid responsiveness.

FINDINGS

The demographic characteristics of COVID-19 patients were comparable with those of controls. SARS-CoV-2-like particles were identified in the adrenocortical cells of three patients; however, these particles did not affect cellular morphology or steroid synthesis compared with SARS-CoV-2-negative specimens. Although the adrenals exhibited focal necrosis, vacuolization, microthrombi, and inflammation, widespread degeneration was not evident. Notably, corticosteroid biosynthesis was significantly enhanced in both the ZG and ZF of COVID-19 patients. The increase in the inflammatory response and cellular differentiation in the adrenal cortices of patients with critical COVID-19 was positively correlated with heightened steroidogenic activity. Additionally, the appearance of more dual-ZG/ZF identity cells in COVID-19 adrenals was in accordance with the increased steroidogenic function. However, activated mineralocorticoid and glucocorticoid receptors and their responsive genes in vital tissues were markedly reduced in patients with critical COVID-19.

INTERPRETATION

Critical COVID-19 was characterized by potentiated adrenal steroidogenesis, associated with increased inflammation, enhanced differentiation and elevated dual-ZG/ZF identity cells, alongside suppressed corticosteroid responsiveness. These alterations implied the reduced effectiveness of conventional corticosteroid therapy and underscored the need for evaluation of the adrenal axis and corticosteroid sensitivity.

Future directions for adrenal insufficiency: cellular transplantation and genetic therapies

Primary adrenal insufficiency occurs in 1 in 5-7000 adults. Leading aetiologies are autoimmune adrenalitis in adults and congenital adrenal hyperplasia (CAH) in children. Oral replacement of cortisol is lifesaving, but poor quality of life, repeated adrenal crises and dosing uncertainty related to lack of a validated biomarker for glucocorticoid sufficiency, persists. Adrenocortical cell therapy and gene therapy may obviate many of the shortcomings of adrenal hormone replacement. Physiological cortisol secretion regulated by pituitary adrenocorticotropin, could be achieved through allogeneic adrenocortical cell transplantation, production of adrenal-like steroidogenic cells from either stem cells or lineage conversion of differentiated cells, or for CAH, gene therapy to replace or repair a defective gene. The adrenal cortex is a high turnover organ and thus failure to incorporate progenitor cells within a transplant will ultimately result in graft exhaustion. Identification of adrenocortical progenitor cells is equally important in gene therapy where new genetic material must be specifically integrated into the genome of progenitors to ensure a durable effect. Delivery of gene editing machinery and a donor template, allowing targeted correction of the 21-hydroxylase gene, has the potential to achieve this. This review describes advances in adrenal cell transplants and gene therapy that may allow physiological cortisol production for children and adults with primary adrenal insufficiency.

Extension of Survival in Bilaterally Adrenalectomized Mice by Implantation of SF-1/Ad4BP-Induced Steroidogenic Cells

Mesenchymal stroma/stem cells (MSCs) exist in adult tissues, such as adipose tissue and bone marrow, and differentiate into cells of multiple lineages. In previous studies, we found that MSCs differentiate into steroidogenic cells by forced expression of steroidogenic factor 1 (SF-1)/adrenal 4 binding protein (Ad4BP), the master regulator of steroidogenesis and differentiation of pituitary gonadotrophs, adrenal glands, and gonads. In this study, SF-1/Ad4BP-induced steroidogenic cells derived from mouse adipose tissue-derived MSCs (ADSCs) were implanted under the kidney capsule of bilateral adrenalectomized (bAdx) mice. bAdx mice did not survive after 7 days. However, 4 of 9 bAdx mice implanted with SF-1/Ad4BP-induced steroidogenic cells, 1 of 10 bAdx mice transplanted with control ADSCs, and bAdx mice transplanted with an adrenal gland survived for 30 days. Plasma corticosterone levels in bAdx mice implanted with SF-1/Ad4BP-induced steroidogenic cells and control ADSCs were 5.41 ± 2.26 ng/mL (mean ± SEM) and undetectable at 7 days after implantation, respectively. After removal of the kidney bearing the graft from the surviving mice at 30 days after implantation, plasma corticosterone was not detected in any of the samples. Immunohistochemical staining revealed SF-1/Ad4BP-positive cells under the capsule of the kidney. Although we performed an adrenocorticotropin (ACTH) loading test on bAdx mice implanted with SF-1/Ad4BP-induced steroidogenic cells, ACTH responsiveness was not observed. Implantation of steroidogenic cells derived from ADSCs into bAdx mice increased the basal plasma corticosterone level and extended the survival of bAdx mice, suggesting the capability of restoring steroidogenic cells by cell transplantation therapy for adrenal insufficiency.

The Adrenal Cortex, an Underestimated Site of SARS-CoV-2 Infection

BACKGROUND

The majority of the critically ill patients may have critical illness-related corticosteroid insufficiency (CIRCI). The therapeutic effect of dexamethasone may be related to its ability to improve cortical function. Recent study showed that dexamethasone can reduce COVID-19 deaths by up to one third in critically ill patients. The aim of this article is to investigate whether SARS-CoV-2 can attack the adrenal cortex to aggravate the relative adrenal insufficiency.

METHODS

We summarized the clinical features of COVID-19 reported in currently available observational studies. ACE2 and TMPRSS2 expression was examined in human adrenal glands by immunohistochemical staining. We retrospectively analyzed serum cortisol levels in critically ill patients with or without COVID-19.

RESULTS

High percentage of critically ill patients with SARS-COV-2 infection in the study were treated with vasopressors. ACE2 receptor and TMPRSS2 serine protease were colocalized in adrenocortical cells in zona fasciculata and zona reticularis. We collected plasma cortisol concentrations in nine critically ill patients with COVID-19. The cortisol levels of critically ill patients with COVID-19 were lower than those in non-COVID-19 critically ill group. Six of the nine COVID-19 critically ill patients had random plasma cortisol concentrations below 10 µg/dl, which met the criteria for the diagnosis of CIRCI.

CONCLUSION

We demonstrate that ACE2 and TMPRSS2 are colocalized in adrenocortical cells, and that the cortisol levels are lower in critically ill patients with COVID-19 as compared to those of non-COVID-19 critically ill patients. Based on our findings, we recommend measuring plasma cortisol level to guide hormonal therapy.

Genetics of Congenital Adrenal Hyperplasia

Congenital adrenal hyperplasia (CAH) refers to a group of autosomal recessive disorders due to single-gene defects in the various enzymes required for cortisol biosynthesis. CAH represents a continuous phenotypic spectrum with more than 95% of all cases caused by 21-hydroxylase deficiency. Genotyping is an important tool in confirming the diagnosis or carrier state, provides prognostic information on disease severity, and is essential for genetic counseling. In this article, the authors provide an in-depth discussion on the genetics of CAH, including genetic diagnosis, molecular analysis, genotype-phenotype relationships, and counseling of patients and their families.

Role of ALADIN in human adrenocortical cells for oxidative stress response and steroidogenesis

Triple A syndrome is caused by mutations in AAAS encoding the protein ALADIN. We investigated the role of ALADIN in the human adrenocortical cell line NCI-H295R1 by either over-expression or down-regulation of ALADIN. Our findings indicate that AAAS knock-down induces a down-regulation of genes coding for type II microsomal cytochrome P450 hydroxylases CYP17A1 and CYP21A2 and their electron donor enzyme cytochrome P450 oxidoreductase, thereby decreasing biosynthesis of precursor metabolites required for glucocorticoid and androgen production. Furthermore we demonstrate that ALADIN deficiency leads to increased susceptibility to oxidative stress and alteration in redox homeostasis after paraquat treatment. Finally, we show significantly impaired nuclear import of DNA ligase 1, aprataxin and ferritin heavy chain 1 in ALADIN knock-down cells. We conclude that down-regulating ALADIN results in decreased oxidative stress response leading to alteration in steroidogenesis, highlighting our knock-down cell model as an important in-vitro tool for studying the adrenal phenotype in triple A syndrome.

Hydrogen peroxide responsive miR153 targets Nrf2/ARE cytoprotection in paraquat induced dopaminergic neurotoxicity

Epidemiological and animal studies suggest that environmental toxins including paraquat (PQ) increase the risk of developing Parkinson's disease (PD) by damaging nigrostriatal dopaminergic neurons. We previously showed that overexpression of a group of microRNAs (miRs) affects the antioxidant promoting factor, Nrf2 and related glutathione-redox homeostasis in SH-SY5Y dopaminergic neurons. Although, dysregulation of redox balance by PQ is well documented, the role for miRs and their impact have not been elucidated. In the current study we investigated whether PQ impairs Nrf2 and its related cytoprotective machinery by misexpression of specific fine tune miRs in SH-SY5Y neurons. Real time PCR analysis revealed that PQ significantly (p<0.05) increased the expression of brain enriched miR153 with an associated decrease in Nrf2 and its function as revealed by decrease in 4× ARE activity and expression of GCLC and NQO1. Also, PQ and H2O2-induced decrease in Nrf2 3' UTR activity was restored on miR153 site mutation suggesting a 3' UTR interacting role. Overexpression of either anti-miR153 or Nrf2 cDNA devoid of 3' UTR prevented PQ and H2O2-induced loss in Nrf2 activity confirming that PQ could cause miR153 to bind to and target Nrf2 3' UTR thereby weakening the cellular antioxidant defense. Adenovirus mediated overexpression of cytoplasmic catalase (Ad cCAT) confirmed that PQ induced miR153 is hydrogen peroxide (H2O2) dependent. In addition, Ad cCAT significantly (p<0.05) negated the PQ induced dysregulation of Nrf2 and function along with minimizing ROS, caspase 3/7 activation and neuronal death. Altogether, these results suggest a critical role for oxidant mediated miR153-Nrf2/ARE pathway interaction in paraquat neurotoxicity. This novel finding facilitates the understanding of molecular mechanisms and to develop appropriate management alternatives to counteract PQ-induced neuronal pathogenesis.

Effects of damage-regulated autophagy regulator gene on the SGC7901 human gastric cancer cell line

The aim of this study was to investigate the effects of the adenoviral-mediated autophagy gene, damage-regulated autophagy regulator (DRAM), on the proliferation and autophagy of SGC7901 human gastric cancer cells in vitro. The recombinant adenovirus, AdMax-pDC315-DRAM-EGFP, working as a virus vector of DRAM was constructed and infected into the SGC7901 human gastric cancer cell line. The MTT assay was used to determine the growth rate of the SGC7901 cells. Activation of autophagy was monitored with monodansylcadaverin (MDC) staining following AdMax-pDC315-DRAM-EGFP treatment. Immunofluorescent staining was used to examine the expression of microtubule-associated protein 1 light chain 3 (LC3), and western blotting was used to examine the expression of apoptosis- and autophagy-associated proteins, including Beclin1, p53, p21 and B-cell lymphoma 2 (Bcl-2), in the culture supernatant. The viability of the SGC7901 cells was activated by AdMax-pDC315-DRAM-EGFP treatment. The AdMax-pDC315-DRAM-EGFP-treated cells exhibited positive LC3 expression detected by immunoreactivity and MDC staining. Inductions in the expression of the apoptosis-related proteins, p53 and p21, and the autophagic protein, Beclin1, were revealed by western blot analysis. By contrast, downregulation of the apoptosis-related protein, Bcl-2, following AdMax-pDC315-DRAM-EGFP treatment was identified. In conclusion, the present study demonstrated that AdMax-pDC315-DRAM-EGFP treatment resulted in upregulation of the level of autophagy and induction of cell proliferation in the SGC7901 human gastric cancer cell line in vitro.

Adrenal gland infection by serotype 5 adenovirus requires coagulation factors

Recombinant, replication-deficient serotype 5 adenovirus infects the liver upon in vivo, systemic injection in rodents. This infection requires the binding of factor X to the capsid of this adenovirus. Another organ, the adrenal gland is also infected upon systemic administration of Ad, however, whether this infection is dependent on the cocksackie adenovirus receptor (CAR) or depends on the binding of factor X to the viral capsid remained to be determined. In the present work, we have used a pharmacological agent (warfarin) as well as recombinant adenoviruses lacking the binding site of Factor X to elucidate this mechanism in mice. We demonstrate that, as observed in the liver, adenovirus infection of the adrenal glands in vivo requires Factor X. Considering that the level of transduction of the adrenal glands is well-below that of the liver and that capsid-modified adenoviruses are unlikely to selectively infect the adrenal glands, we have used single-photon emission computed tomography (SPECT) imaging of gene expression to determine whether local virus administration (direct injection in the kidney) could increase gene transfer to the adrenal glands. We demonstrate that direct injection of the virus in the kidney increases gene transfer in the adrenal gland but liver transduction remains important. These observations strongly suggest that serotype 5 adenovirus uses a similar mechanism to infect liver and adrenal gland and that selective transgene expression in the latter is more likely to be achieved through transcriptional targeting.

Intravenous administration of endothelial progenitor cells transfected with the TRAIL gene inhibits the growth of tumors derived from H22 cells in nude mice

AIM: To investigate the influence of intravenous administration of endothelial progenitor cells (EPCs) transfected with the TRAIL gene on the growth of tumors derived from subcutaneously inoculated H22 cells in nude mice to provide a theoretical basis for the treatment of liver cancer.

METHODS: The TRAIL gene was amplified by PCR, cloned into the pcDNA3.1 vector, and transfected into EPCs. The expression of TRAIL protein was detected by Western blot. Mice were inoculated subcutaneously with H22 cells to induce tumor formation. Tumor-bearing mice were randomly divided into three groups and injected via the tail vein with EPCs transfected with the recombinant adenoviral vector carrying the TRAIL gene, the empty vector, and normal saline, respectively.

RESULTS: Restriction enzyme digestion and DNA sequencing analyses indicate that the recombinant plasmid was constructed successfully. TRAIL expression was detected in EPCs transfected with the recombinant adenoviral vector by Western blot. The rate of reduced tumor growth was 47.77% in mice administered with EPCs carrying the TRAIL gene. Tumor volume and weight in the experimental group (0.791 cm3 ± 0.119 cm3, 0.29 g ± 0.04 g) were significantly lower than those in the two control groups (all P < 0.05).

CONCLUSION: The recombinant plasmid carrying the TRAIL gene has been successfully constructed. Intravenous administration of endothelial progenitor cells transfected with the TRAIL gene inhibits the growth of tumors derived from H22 cells in nude mice.

Congenital adrenal hyperplasia--pharmacologic interventions from the prenatal phase to adulthood

Congenital adrenal hyperplasia (CAH) is one of the most common inherited autosomal recessive disorders, caused by deficiency of one of the enzymes involved in steroid synthesis. The clinical picture of the most prevalent form, i.e. 21-hydroxylase deficiency, is characterized by cortisol and mostly aldosterone deficiency and androgen excess (leading to congenital virilization in girls). Treatment consists of glucocorticoids, aimed at substitution of cortisol deficiency and, decrease of androgen excess. Usually supraphysiological doses of glucocorticoids are required to effectively suppress adrenal androgens. Furthermore, with the currently available glucocorticoid preparations, it is not possible to simulate a normal circadian rhythm in CAH patients. Therefore, it is a difficult task for (pediatric) endocrinologists to find the best balance between under- and overtreatment thereby avoiding important long term complications. In this review we will discuss the current pharmacologic treatment options. We give age dependent dose recommendations and describe the limitations of current treatment strategies. We discuss effects on fertility, bone density and cardiovascular risks. Recommendations about the use of glucocorticoids in case of fever or stress situations are given. The principles of treatment of non classic (mild) CAH are discussed in a separate section. Also prenatal therapy, to prevent congenital virilization of a female CAH newborn, is discussed. Furthermore, an overview of alternative pharmacological treatment options in the future is given.

Alternative strategies for the treatment of classical congenital adrenal hyperplasia: pitfalls and promises

Despite decades of different treatment algorithms, the management of congenital adrenal hyperplasia (CAH) remains clinically challenging. This is due to the inherent difficulty of suppressing adrenal androgen production using near physiological dosing of glucocorticoids (GC). As a result, alternating cycles of androgen versus GC excess can occur and may lead to short stature, obesity, virilization, and alterations in puberty. Novel therapeutic alternatives, including new and more physiological means of GC delivery, inhibitors at the level of CRH or ACTH secretion and/or action, as well as “rescue strategies”, such as GnRH analogs, anti-androgens, aromatase inhibitors, and estrogen receptor blockers, are available; many of these agents, however, still require active investigation in CAH. Bilateral adrenalectomy is effective but it is also still an experimental approach. Gene therapy and stem cells, to provide functional adrenal cortical tissue, are at preclinical stage but provide exciting avenues for a potential cure for CAH.

Investigation on human adrenocortical cell response to adenovirus and adenoviral vector infection

After systemic administration, adenoviral vectors (AdVs) are sequestered in the liver and adrenal glands. Adenoviral vector transduction has been shown to cause cytopathic effects on human hepatocytes and to induce an inflammatory response, whereas the effect of AdVs on human adrenocortical cells has never been investigated. In this study, human adrenocortical carcinoma cell lines and primary cell cultures were used to assess the effects of wild-type adenovirus (Ad5WT) and E1/E3-deleted AdVs on cell proliferation and steroidogenesis. Ad5WT could efficiently replicate in adrenocortical cells, leading to S phase induction, followed by cell death, whereas high titer AdVs transduction had only mild effects on adrenocortical cell proliferation, with accumulation of cells in G2/M. Both AdVs and Ad5WT induced expression of inflammatory cytokines, such as interleukin-6 and tumor necrosis factor-alpha, but, most importantly, they led to a marked and dose-dependent increase of cortisol and other steroid hormone production and consistently modulated expression of key steroidogenic enzymes and regulators of steroidogenesis. This effect, which was already apparent at 6 h post-infection, probably represented a response to adenoviral entry and/or early phases of infection. The result of this study contribute to the understanding of host response to adenoviral vector administration.

Genetics of congenital adrenal hyperplasia

Congenital adrenal hyperplasia (CAH) is one of the most common inherited metabolic disorders. It comprises a group of autosomal recessive disorders caused by the deficiency of one of four steroidogenic enzymes involved in cortisol biosynthesis or in the electron donor enzyme P450 oxidoreductase (POR) that serves as electron donor to steroidogenic cytochrome P450 (CYP) type II enzymes. The biochemical and clinical phenotype depends on the specific enzymatic defect and the impairment of specific enzyme activity. Defects of steroid 21-hydroxylase (CYP21A2) and 11beta-hydroxylase (CYP11B1) only affect adrenal steroidogenesis, whereas 17alpha-hydroxylase (CYP17A1) and 3beta-hydroxysteroid dehydrogenase type 2 (HSD3B2) deficiency also impact on gonadal steroid biosynthesis. Inactivating POR gene mutations are the cause of CAH manifesting with apparent combined CYP17A1-CYP21A2 deficiency. P450 oxidoreductase deficiency (ORD) has a complex phenotype including two unique features not observed in any other CAH variant: skeletal malformations and severe genital ambiguity in both sexes.

New methods for investigating experimental human adrenal tumorigenesis

Adenomas and nodules of the human adrenal cortex are common, whereas adrenocortical carcinomas are rare. Genes such as IGF2 have been suggested to be important in human adrenocortical tumorigenesis but their role has not been directly investigated. We describe here elements of a system in which hypotheses concerning the molecular basis for the formation of benign and malignant adrenocortical lesions can be experimentally tested. Various viral vectors have been employed in the study of adrenocortical cell biology. Because of the low proliferative rate of primary human adrenocortical (pHAC) cells, a lentiviral system is ideal for transducing these cells with genes that may alter their characteristics or cause them to acquire benign or malignant tumorigenicity. Cultures of pHAC cells were highly infectible with lentiviruses and showed a higher proliferative potential when transduced with a lentivirus encoding IGF2. For tumorigenesis studies of genetically modified adrenocortical cells, we use RAG2(-/-), gammac(-/-) mice. Using this immunodeficient mouse model, we established an orthotopic intra-adrenal cell transplantation technique for adrenocortical cells that should be of value for future studies of the experimental conversion of human adrenocortical cells to a benign or malignant tumorigenic state.

Adenoviral gene transfer in bovine adrenomedullary and murine pheochromocytoma cells: potential clinical and therapeutic relevance

Recombinant adenoviruses (rAd) have been widely used as gene transfer vectors both in the laboratory and in human clinical trials. In the present study, we investigated the effects of adenoviral-mediated gene transfer in primary bovine adrenal chromaffin cells (BACC) and a murine pheochromocytoma cell line (MPC). Cells were infected with one of three nonreplicating E1/E3-deleted (E1(-)/E3(-)) rAd vectors: Ad.GFP, expressing a green fluorescent protein (GFP); Ad.null, expressing no transgene; or Ad.C2.TK, expressing the herpes simplex virus-1 thymidine kinase gene (TK). Forty-eight hours after exposure to Ad.GFP, the percentage of GFP-expressing BACC ranged from 23.5-97% in a dose-dependent manner and similarly from 1.06-84.4% in the MPC, indicating that adrenomedullary cells are a potentially valuable target for adenoviral-mediated gene transfer. Ultrastructural analysis, however, revealed profound changes in the nucleus and mitochondria of cells infected with rAd. Furthermore, infection of BACC with Ad.null was accompanied by a time- and dose-dependent decrease in cell survival due to the vector alone. Specific whole-cell norepinephrine uptake was also decreased in a time- and dose-dependent fashion in BACC. Infection of MPC cells with the Ad.C2.TK vector sensitized them to the cytotoxic effect of the antiviral drug ganciclovir, in direct proportion to the fraction of cells infected with the virus. We conclude that rAd may alter the structural and functional integrity of adrenomedullary cells, potentially interfering with the normal stress response. At the same time, in light of their ability to effectively deliver and express genes in pheochromocytoma cells, they may be applicable to the gene therapy of adrenomedullary tumors.

Mitochondrial localization of human recombinant adenovirus: from evolution to gene therapy

Mitochondrial research has influenced concepts in anthropology, human physiology and pathophysiology. We present here direct evidence that human recombinant viruses can localize in mitochondria to disrupt their integrity. This finding, while opening new perspectives in viral gene therapy, may provide new insights into the pathogenesis, prevention and treatment of viral diseases. In addition, it may advance the current understanding of cell evolution.

Differentiation and regeneration of adrenal tissues: An initial step toward regeneration therapy for steroid insufficiency

In animal experiments, adrenal cortical tissue has been successfully regenerated through xenotransplantation of cloned adrenocortical cells, suggesting that the intraadrenal stem cells required for such tissue formation may be present in the adrenal cortex. Stable expression of Ad4BP/SF-1, a key factor for adrenal and gonadal development and steroidogenesis, has been shown to direct embryonic stem cells toward the steroidogenic lineage. However, this steroidogenic capacity was very limited since progesterone was only produced in the presence of an exogenous substrate. Bone marrow mesenchymal cells are thought to contain pluripotent progenitor cells, which differentiate into multiple lineages. We have demonstrated that adenovirus-mediated forced expression of SF-1 in long-term cultured bone marrow cells can produce steroidogenic cells with the capacity for de novo synthesis of various steroid hormones in response to ACTH. This discovery may represent the first step in autologous cell transplantation therapy for patients with steroid hormone deficiency.

Impact of reductive cleavage of an intramolecular disulfide bond containing cationic gemini surfactant in monolayers and bilayers

The properties of a novel disulfide-bond-containing gemini surfactant bis[N,N-dimethyl-N-hexadecyl-N-(2-mercaptoethyl)ammonium bromide] disulfide (DSP) were studied using a Langmuir balance, supported monolayers, differential scanning calorimetry, giant vesicles, and LUVs. In 150 mM NaCl the cmc for DSP was 7.5 microM whereas that of the monomer N,N-dimethyl-N-hexadecyl-N-(2-mercaptoethyl)ammonium bromide (MSP) was 12.1 microM. Both surfactants exhibited single endotherms upon DSC, with peak temperatures Tm at 21.7 and 20.1 degrees C for DSP and MSP, respectively. The endotherm for MSP was significantly broader indicating less cooperative melting. Both in monolayers and in vesicles reductive cleavage of the disulfide bond of DSP could be obtained by glutathione (GSH). For Langmuir films of DSP the addition of GSH into the subphase led to a decrease in surface pressure pi as well as surface dipole potential psi. Although the cleavage by GSH was significantly slower in the presence of a charge saturating concentration of DNA, it did not prevent the reaction. The resulting monomers detached from supported monolayers, leading to loss of affinity of the surface for DNA. Disruption of giant vesicles containing DSP within approximately 30 s following a local injection of GSH was observed, revealing membrane destabilization.

Transient overexpression of gamma interferon promotes Aspergillus clearance in invasive pulmonary aspergillosis

Cytokines are critical molecules necessary for normal lung pathogen host defences. Gamma interferon (IFN-gamma) and T1-phenotype immune responses are important components of host defence against Aspergillus. Therefore, we hypothesized that transient overexpression of IFN-gamma within the lung could augment host immunity against Aspergillus. Here it was showed that intranasal administration of 5 x 10(7) colony-forming units (CFU) of Aspergillus fumigatus (Af ) induced the expression of IFN-gamma. Mice were intranasally (i.n) administrated with 5 x 10(8) PFU of a recombinant adenovirus vector containing the murine IFN-gamma cDNA (AdmIFN-gamma), and challenged 24 h later with Af. We observed that i.n. administration of AdmIFN-gamma resulted in about a fourfold increase in levels of IFN-gamma and IL-12 within the lung, about a 75% reduction in lung fungal contents at day 2 and a more than threefold higher survival rate in the AdmIFN-gamma-treated group compared to the controls (P < 0.01). This protection effect was not found when AdmIFN-gamma was i.p. administrated. Alveolar macrophages and lung leucocytes isolated from i.n. AdmIFN-gamma-treated animals displayed enhanced killing of intracellular Aspergillus organisms ex vivo. These results demonstrate that transient overexpression of IFN-gamma could augment host defence against Aspergillus.

Increasing surface charge density induces interdigitation in vesicles of cationic amphiphile and phosphatidylcholine

Binary vesicles of cationic lipid dihexadecyldimethylammoniumbromide (DHAB) and 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) were examined by differential scanning calorimetry, fluorescence spectroscopy, and Fourier transform infrared spectroscopy. DHAB/DMPC vesicles demonstrate a complex dependence of the main-transition temperature (T(m)) on their mole proportion of DHAB, with a maximum of 42 degrees C at X(DHAB) = 0.4. An increase of T(m) at X(DHAB) < 0.4 is explained by reorientation of P(-)-N(+) dipoles of the phosphocholine headgroup, resulting in tighter packing of the acyl chains, which increases the thermal energy required for trans --> gauche isomerization. At X(DHAB) > 0.4, Coulombic repulsion between the cationic DHAB headgroups expands the bilayer evident as a decrease in T(m) until a plateau of approximately 28 degrees C at 0.7 < or = X(DHAB) > or = 0.9 is reached, followed by an increment of T(m) to approximately 30 degrees C at X(DHAB) > 0.9. The quenching of DPH-PC fluorescence emission and the decrease in the ratio of peak height intensities of symmetric and antisymmetric -CH(2)- stretching modes suggest an interdigitated phase to form at X(DHAB) > 0.6. Interdigitation allows the membrane to accommodate the augmented Coulombic repulsion between DHAB headgroups because of increasing cationic surface charge density while simultaneously causing tighter packing of the acyl chains evident first as a plateau at 0.7 < or = X(DHAB) > or = 0.9 and subsequently as an increase in T(m) at X(DHAB) > 0.9. Screening of the membrane charges by NaCl abolishes the quenching of DPH emission and decreases T(m), thus revealing electrostatic repulsion as the driving force for interdigitation.

Congenital adrenal hyperplasia

Congenital adrenal hyperplasia (CAH) due to deficiency of 21-hydroxylase is a disorder of the adrenal cortex characterised by cortisol deficiency, with or without aldosterone deficiency, and androgen excess. Patients with the most severe form also have abnormalities of the adrenal medulla and epinephrine deficiency. The severe classic form occurs in one in 15,000 births worldwide, and the mild non-classic form is a common cause of hyperandrogenism. Neonatal screening for CAH and gene-specific prenatal diagnosis are now possible. Standard hormone replacement fails to achieve normal growth and development for many children with CAH, and adults can experience iatrogenic Cushing's syndrome, hyperandrogenism, infertility, or the development of the metabolic syndrome. This Seminar reviews the epidemiology, genetics, pathophysiology, diagnosis, and management of CAH, and provides an overview of clinical challenges and future therapies.

Adenoviral-mediated transduction of human pancreatic islets: importance of adenoviral genome for cell viability and association with a deficient antiviral response

As adenoviral vectors are extensively used for genetic manipulation of insulin-producing cells in vitro, there is an increasing need to evaluate their effects on the function, morphology, and viability of transduced pancreatic islets. In the present study we observed that specific adenoviral genotypes, carrying E4 and E1/E3 deletions, correlate with differential induction of necrosis in pancreatic islet cells. In particular, the adenovirus death protein encoded from the E3 region of the adenoviral genome was able to modulate the changes induced in the morphology and viability of the transduced cells. We also propose a putative role for the transcriptional regulator pIX. Although human islet cells showed an increased resistance in terms of viral concentrations required for the induction of cell toxicity, our results showed that they were unable to build up an efficient antiviral response after transduction and that their survival was dependent on the exogenous addition of alpha-interferon. An intact and fully functional beta-cell is crucial for the successful application of gene therapy approaches in type 1 diabetes, and therefore, the implications of our findings need to be considered when designing vectors for gene transfer into pancreatic beta-cells.

Platelet derived growth factor (PDGF)-induced reactive oxygen species in the lens epithelial cells: the redox signaling

Low level of reactive oxygen species (ROS) has been shown to play an important role in host defense and mediating mitogen-stimulated cell signaling in several cell types. This study is to identify the mitogen-induced endogenous ROS generation and the range of exogenous H(2)O(2) that initiate redox signaling and cell proliferation in human lens epithelial cells (HLE B3), using platelet-derived growth factor (PDGF) as a model. To detect ROS generation, serum starved HLE cells (1.6 million) were loaded with fluorescent dye, 2',7'-dichlorofluorescin diacetate (DCFH-DA), before exposing to PDGF (1 ng ml(-1)). The fluorescence generated from the oxidant-sensitive DCFH, the intracellular product of DCFH-DA hydrolysate, was immediately measured in live cells by confocal laser light microscopy (lambda(Ex)=488 nm, lambda(Em)=522 nm, laser power=10%). PDGF-stimulated cells showed strong transient fluorescence during the 60 min while no fluorescence could be seen in the unstimulated cells. The PDGF-induced fluorescence could be suppressed with cells preloaded with N-acetyl-L-cysteine (NAC, 30 mm), catalase (1 mg ml(-1)), or D-mannitol (100mm). The ability of catalase to penetrate and function in HLE cells was confirmed by western blot, enzyme activity and immunofluorescence microscopic analyses. PDGF induced DNA synthesis within one hour as measured by (3)H-thymidine incorporation, and transiently activated the mitogen-activated protein kinases (MAPKs) of ERK1/2 and JNK. PDGF-stimulated DNA synthesis and MAPK activation were eliminated in the presence of catalase or mannitol. Low levels of H(2)O(2) (10-20 microm) mimicked PDGF in both MAPK stimulation and cell proliferation. In conclusion, the mitogenic stimulus function of PDGF in HLE cells appears to be mediated via ROS to activate MAPKs and cell proliferation, which can be mimicked by low levels of H(2)O(2). It is proposed that the physiological function of ROS, the redox signaling, is present in the HLE cells and may play an important role in the development and maintenance of the lens.

Steroidogenic acute regulatory (StAR)-directed immunotherapy protects against tumor growth of StAR-expressing Sp2-0 cells in a rodent adrenocortical carcinoma model

Adrenocortical carcinoma (ACC) is a highly malignant tumor with poor response to classical antitumor therapy. Steroidogenic acute regulatory (StAR) protein is expressed in most human ACCs. The aim of this study was to induce antitumoral T cells directed against StAR in a murine tumor model. Because a suitable syngenic adrenocortical mouse tumor model is lacking, we established a clone of the mouse myeloma Sp2-0 tumor cell line stably expressing murine StAR (Sp2-mStAR). Using repeated im injections of plasmid DNA encoding mStAR followed by infection with a recombinant vaccinia virus (rVV) expressing mStAR, we induced a cytotoxic T-cell response as measured by enzyme-linked immunospot assay. To demonstrate antitumor activity of the vaccination procedure, mice were treated as follows: group A, mice immunized with plasmids and rVV encoding mStAR receiving Sp2-mStAR cells; control group B, mice immunized with the empty plasmid and the empty rVV receiving Sp2-mStAR cells; control group C, mice immunized with the empty plasmid and rVV encoding P450 side-chain cleavage enzyme receiving Sp2-mStAR cells; and control group D, mice immunized with plasmid and rVV encoding mStAR receiving parental Sp2-0 cells. A high proportion (89-100%) of the control groups B, C, and D developed subcutaneous tumors. In contrast, immunization specific for mStAR (group A) was highly protective against tumor growth (percentage of tumor-free animals, 67%; P < 0.001 vs. controls). In summary, these results show that T-cell tolerance toward mStAR can be broken, resulting in antitumoral immunity. Thus, StAR represents a candidate target antigen for immunotherapeutic strategies against ACC.

Endocrine aspects of cancer gene therapy

The field of cancer gene therapy is in continuous expansion, and technology is quickly moving ahead as far as gene targeting and regulation of gene expression are concerned. This review focuses on the endocrine aspects of gene therapy, including the possibility to exploit hormone and hormone receptor functions for regulating therapeutic gene expression, the use of endocrine-specific genes as new therapeutic tools, the effects of viral vector delivery and transgene expression on the endocrine system, and the endocrine response to viral vector delivery. Present ethical concerns of gene therapy and the risk of germ cell transduction are also discussed, along with potential lines of innovation to improve cell and gene targeting.

Cellular characterization of the tropism of recombinant adenovirus for the adrenal glands

BACKGROUND

Recombinant adenoviruses are widely used in gene therapy clinical trials. A particular tropism for the adrenal glands has been reported but the precise cellular base for this tropism has not been determined.

MATERIALS AND METHODS

Recombinant adenoviruses were injected intravenously into Balb/c nu/nu or C57BL/6 mice. Seventy-two hours later, the animals were sacrificed and the adrenal glands and livers collected. The glands were sectioned and analyzed using immunohistochemical methods to detect adenoviral epitopes and transgene expression. Total RNA were extracted from the liver and adrenal glands of some animals and subjected to real-time RT-PCR.

RESULTS

The only cell type infected in the adrenal glands of Balb/c nu/nu or C57BL/6 mice is the adrenocortical cells in the zona fasciculata. Quantitatively, the relative level of gene expression in the adrenal gland is comparable but lower than that measured in the liver.

CONCLUSIONS

Systemic injection of recombinant adenovirus could be used as a procedure to restore adrenal steroidogenesis in clinical gene therapy protocols. In addition, our study suggest that adrenal dysfunction should be considered when criteria are established to assess the safety of gene therapy formulations administered systemically.

Construction, package and identification of replication-deficient recombinant adenovirus expression vector of HCV C

AIM: To construct a replication-deficient recombinant adenovirus expression vector of HCV C.

METHODS: The HCV core gene was cloned at the downstream of CMV promoter of the adenoviral shuttle plasmid pAd. CMV-link. 1, and the resultant recombinant plasmid pAd. HCV-C was cotransfected into 293 cell together with plasmid pJM17 containing adenoviral genome, then the adenovirus expression vector was obtained, and identified by infecting test, electronic microscope observation and PCR co-amplification. The plasmid pAd. HCV-C was identified by endonuclease, PCR and sequencing. The expressive activity of adenovirus vector was identified by immunofluorescence and Western blot.

RESULTS: HCV core gene in the inserted DNA of pAd. HCV-C was confirmed by endonuclease, PCR and sequencing. Results of infecting test, electronic microscopic observation and PCR co-amplification showed that the adenovirus vector had been constructed successfully. Expression of HCV core antigen was proved in the HepG2 cells by immunofluorescence and Western blot.

CONCLUSION: The replication-deficient recombinant adenovirus vector can express HCV core antigen in HepG2 cells. This study established a foundation for further study on HCV vaccines and gene therapy for hepatitis C.

Genomic medicine: exploring the basis of a new approach to endocrine hypertension

Recent improvements in defining the molecular basis of disease have encouraged scientists worldwide to develop new therapeutic strategies based on engineered genes and cells. Genomic medicine has the potential to revolutionize diagnosis and therapy of a variety of human diseases, including endocrine disorders. Hypertension is the presenting feature of some of these disorders, such as congenital adrenal diseases, and adrenal and pituitary tumors. Preclinical data indicate that gene transfer to both the adrenal gland and the pituitary is not only feasible but also quite efficient. Research in this field is only in its infancy, but with the ever-increasing advances in DNA technologies, genomic therapies for endocrine hypertension may become available within the next few decades.