A new mouse model for renal lesions produced by intravenous injection of diphtheria toxin A-chain expression plasmid

The dark side of miracle plant-Aloe vera: a review

BACKGROUND

Aloe vera (Aloe barbadensis Miller), commonly known as Ghritkumari/Gwarpatha, is a member of the Liliaceae family, used in the traditional medicine system for ages. Aloe vera has made its importance as a therapeutic agent, acting as a cure for various diseases such as skin problems, lungs, and heart disorders, diabetes, ulcers, various microbial infections, and asthma. Despite its tremendous health benefits, the dark side of the plant is a reason of concern as there are several active compounds present in the plant, raising questions on its safe oral consumption and application.

METHODS AND RESULTS

The literature review was compiled from information resourced from various national and international journals available at Google Scholar and curated with Mendeley. The data mining was carried out during the period of January to May 2021. This study explored and summarized the dark side of Aloe vera, subjected to various secondary metabolites present in it. Aloin, the most active compound of Aloe vera, is a type of anthraquinone metabolized by human gut microflora, resulting in the formation of aloe-emodin anthraquinone, later being associated with several harmful effects such as carcinogenicity, genotoxicity, nephrotoxicity, and purgative. Besides this, several alkaloids and polysaccharides present in the plant are reported to cause hepatotoxicity and male infertility, respectively.

CONCLUSIONS

The harmful effects of the plants are not adequately discovered yet; hence there is a need to come up with some mechanism to understand and suppress the formation of such toxic compounds completely. This review examined the botany, active compounds, and adverse clinical effects in the range of metabolites associated with this herb - "Aloe vera".

Development of Novel Heparin/Protamine Nanoparticles Useful for Delivery of Exogenous Proteins In Vitro and In Vivo

We previously reported that heparin/protamine particles (LHPPs) produced as nanoparticles through simple mixing of raw materials exhibit sustained protein release and can be retained in cells. In the present study, we modified LHPPs without employing any organic synthetic approach. The resulting LHPPs were re-named as improved LHPPs (i-LHPPs) and have the ability to retain cell-penetrating peptides (GRKKRRQRRRPPQ) based on electrostatic interactions. We examined whether i-LHPPs can introduce exogenous proteins (i.e., lacZ protein encoding bacterial β-galactosidase) into cultured cells in vitro, or into murine hepatocytes in vivo through intravenous injection to anesthetized mice. We found an accumulation of the transferred protein in both in vitro cultured cells and in vivo hepatocytes. To the best of our knowledge, reports of successful in vivo delivery to hepatocytes are rare. The i-LHPP-based protein delivery technique will be useful for in vivo functional genetic modification of mouse hepatocytes using Cas9 protein-mediated genome editing targeting specific genes, leading to the creation of hepatic disease animal models for research that aims to treat liver diseases.

Nephron ultrastructural alterations induced by zinc oxide nanoparticles: an electron microscopic study

Due to their unique properties, zinc oxide nanoparticles (ZnO NPs) are invested in many industries, commercial products, and nanomedicine with potential risk for human health and the environment. The present study aims to focus on alterations that might be induced by ZnO NPs in the nephron ultrastructure. Male Wister Albino rats were subjected to ZnO NPs at a daily dose of 2 mg/kg for 21 days. Kidney biopsies were processed to transmission electron microscopy (TEM) and ultrastructural pathology examinations. Exposure to ZnO NPs‐induced ultrastructural alterations in the proximal convoluted tubules (PCTs) and to lesser extent in the distal ones (DCTs), while the loops of Henle were almost not affected. The glomeruli demonstrated dilatation, partial mesangial cells loss, matrix ballooning, slits filtration widening, and basement membrane thickening. Moreover, PCT revealed cytoplasmic necrosis, vacuolation, erosion, and disorganisation of the apical microvilli together with mitochondrial swelling and cristae destruction. The nuclei of the renal cells exhibited nuclear deformity, heterochromatin accumulation, and apoptotic activities. The findings indicate that ZnO nanomaterial have the potential to affect the nephron ultrastructure suggesting alteration in the kidney functions. More work is needed for better understanding the toxicity and pathogenesis of ZnO oxide nanomaterial.

Intravenous Delivery of piggyBac Transposons as a Useful Tool for Liver-Specific Gene-Switching

Hydrodynamics-based gene delivery (HGD) is an efficient method for transfecting plasmid DNA into hepatocytes in vivo. However, the resulting gene expression is transient, and occurs in a non-tissue specific manner. The piggyBac (PB) transposon system allows chromosomal integration of a transgene in vitro. This study aimed to achieve long-term in vivo expression of a transgene by performing hepatocyte-specific chromosomal integration of the transgene using PB and HGD. Using this approach, we generated a novel mouse model for a hepatic disorder. A distinct signal from the reporter plasmid DNA was discernible in the murine liver approximately two months after the administration of PB transposons carrying a reporter gene. Then, to induce the hepatic disorder, we first administered mice with a PB transposon carrying a CETD unit (loxP-flanked stop cassette, diphtheria toxin-A chain gene, and poly(A) sites), and then with a plasmid expressing the Cre recombinase under the control of a liver-specific promoter. We showed that this system can be used for in situ manipulation and analysis of hepatocyte function in vivo in non-transgenic (Tg) animals.

Sunset Yellow and Allura Red modulate Bcl2 and COX2 expression levels and confer oxidative stress-mediated renal and hepatic toxicity in male rats

Studies on the adverse health effects caused by azo dyes are insufficient and quite contradictory. This work aims to investigate the possible toxic effect of two types of widely used food additives, Sunset Yellow and Allura Red, by assessing the physiological, histopathological and ultrastructural changes in the liver and kidney. Also, we investigated the genotoxic effect of both dyes on white blood cells. Thirty adult male albino rats were divided into three groups of 10 animals each: control (received water), Sunset Yellow-treated (2.5 mg/kg body weight) and Allura Red-treated (seven mg/kg body weight). The doses were orally applied for 4 weeks. Our results indicated an increase in the biochemical markers of hepatic and renal function (Aspartate aminotransferase, alanine aminotransferase, urea, uric acid and creatinine) in animals administered with the azo dyes. We also observed a noticeable increase in MDA and a marked decrease in total antioxidant levels in azo dye-treated animals compared to controls. Conversely, both dyes adversely affected the liver and kidney of albino rats and altered their histological and fine structure, with downregulation of Bcl2 and upregulation of COX2 expression. Our comet assay results showed a significant elevation in the fold change of tail moment in response to application of Sunset Yellow but not Allura Red. Collectively, we show that Sunset Yellow and Allura Red cause histopathological and physiological aberrations in the liver and kidney of male Wistar albino rats. Moreover, Sunset Yellow but not Allura Red induces a potential genotoxic effect.

Improvement of hydrodynamics-based gene transfer of nonviral DNA targeted to murine hepatocytes

The liver is an important organ for supporting the life of an individual. Gene transfer toward this organ has been attempted in many laboratories to date; however, there have been few reports on improved liver-targeted gene delivery by using a nonviral vector. In this study, we examined the effect of various types of gene delivery carriers on enhancing the uptake and gene expression of exogenous DNA in murine hepatocytes when a hydrodynamics-based gene delivery (HGD) is performed via tail-vein injection. Mice were singly injected with a large amount of phosphate-buffered saline containing reporter plasmid DNA and/or with a gene delivery carrier. One day after the gene delivery, the animals' livers were dissected and subjected to biochemical, histochemical, and molecular biological analyses. The strongest signal from the reporter plasmid DNA was observed when the DNA was mixed with a polyethylenimine- (PEI-) based reagent. Coinjection with pCRTEIL (a loxP-floxed reporter construct) and pTR/NCre (a liver-specific Cre expression vector) resulted in the liver-specific recombination of pCRTEIL. The combination of PEI with HGD would thus be a valuable tool for liver-specific manipulation to examine the function of a gene of interest in the liver and for creating liver disease models.

Histological, ultrastructural and biochemical studies on the kidney of mice treated with Carthamus tinctorius L. extract

OBJECTIVE

Carthamus tinctorius L. (C. tinctorius) is used as a food additive but also has medicinal applications. The present work was designed to investigate its probable side effects on the histology and function of the kidney in the mice.

MATERIALS AND METHODS

Sixty adult Balb/C mice were randomly distributed into one control and three experimental groups. The control group received only distilled water, while experimental groups were administered intraperitoneally C. tinctorius at doses of 0.7, 1.4, and 2.8 mg/kg for 49 consecutive days. In the end of experiments after blood sampling, the biochemical analyses of plasma were performed. Tissue samples were also taken and structural alterations were examined using light and electron microscopes.

RESULTS

There were histological changes included decreasing in the diameter of glomerules, increase of proximal tubular lumen, tubular necrosis, leuckocyte infiltration, and massive congestion in the kidney of the 1.4 and 2.8 mg/kg C. tinctorius groups. Moreover, ultrastructural study revealed destruction of the glomerular basement membrane, shrinkage of podocyte΄s nucleus, and reduction in the number and size of microvilli in epithelial cells of renal tubules. Furthermore, the levels of creatinine in the plasma of 1.4 and 2.8 mg/kg C. tinctorius groups showed a significant increase in comparison with the control group (p<0.05).

CONCLUSION

It is concluded that C. tinctorius extract exposure at doses of 1.4 and 2.8 mg/kg has harmful effects on the renal tissue and therefore, popular consumption of this plant should be reconsidered.

Cre-loxP system as a versatile tool for conferring increased levels of tissue-specific gene expression from a weak promoter

Attempts to image reporter gene expression driven by weak promoters are often hampered by the poor transcriptional activity of such promoters. Most tissue-specific promoters are weak compared with stronger but constitutively expressing viral promoters. In this study, we validated methods of enhancing the transcriptional activity of weak promoters using a Cre-loxP system in vitro and in vivo. We constructed a tester vector, pCTL, which carries a strong systemic cytomegalovirus enhancer/chicken beta-actin promoter (CAG), loxP-flanked CAT, and firefly luciferase (luc) cDNAs. Herpes simplex virus-thymidine kinase (HSV-tk) promoter was used as a weak and systemic promoter and ligated to Cre for construction of pTC. Luc activity was higher (about 10-fold enhancement) in co-transfected (with pCTL and pTC) than in singly (with HSV-tk promoter-driven luc expression vector pTL) transfected NIH3T3 cells. In vivo electroporation-mediated gene delivery of both pCTL and pTC into murine oviductal epithelium yielded results (about 16-fold enhancement) similar to those obtained with in vitro-transfected NIH3T3 cells. To evaluate tissue-specific enhancement of gene expression, podocyte (glomerular visceral epithelial cell)-specific nephrin promoter was ligated to the Cre gene or luc cDNA to create pNC and pNL, respectively. We achieved 2.4-fold improvement of luc gene expression in the mouse kidney in vivo when pCTL and pNC were co-transfected via the tail vein via the lipoplex method. The combination of a weak tissue-specific promoter with the Cre-loxP system could thus be used to enhance the strength of tissue-specific promoters in vitro and in vivo.

Production of CETD transgenic mouse line allowing ablation of any type of specific cell population

Diphtheria toxin A-chain (DT-A) is a potent inhibitor of protein synthesis. As little as a single molecule of DT-A can result in cell death. DT-A gene driven by a tissue-specific promoter is used to achieve genetic ablation of a particular cell lineage. However, this transgenic approach often results in aberrant depletion of unrelated cells. To avoid this, we established a method for specific depletion of a cell population by controlled expression of the DT-A gene via the Cre-loxP system. We produced five transgenic mice carrying CETD construct containing loxP-flanked enhanced green fluorescent protein (EGFP) cDNA and the DT-A gene. Transfection of primary cultured cells derived from CETD transgenic fetus with Cre expression plasmid resulted in extensive cell loss, as expected. Bigenic (double transgenic) offspring obtained by crossbreeding between CETD and MNCE transgenic mice in which Cre expression is controlled by the myelin basic protein (MBP) promoter exhibited embryonic lethality, suggesting expression of Cre at embryonic stages. Intravenous injection of Cre expression vector to CETD mice led to generation of glomerular lesions, probably due to predominant depletion of glomerular epithelial cells. This Cre-loxP-based cell ablation technology is powerful and convenient method of generating mice lacking any chosen cell population.