Improving Dietary Zinc Bioavailability Using New Food Fortification Approaches: A Promising Tool to Boost Immunity in the Light of COVID-19

Zinc is a powerful immunomodulatory trace element, and its deficiency in the body is closely associated with changes in immune functions and viral infections, including SARS-CoV-2, the virus responsible for COVID-19. The creation of new forms of zinc delivery to target cells can make it possible to obtain smart chains of food ingredients. Recent evidence supports the idea that the optimal intake of zinc or bioactive compounds in appropriate supplements should be considered as part of a strategy to generate an immune response in the human body. Therefore, controlling the amount of this element in the diet is especially important for populations at risk of zinc deficiency, who are more susceptible to the severe progression of viral infection and disease, such as COVID-19. Convergent approaches such as micro- and nano-encapsulation develop new ways to treat zinc deficiency and make zinc more bioavailable.

Effect of Bisphenol S on testicular tissue after low-dose lactation exposure

Exposure to endocrine disruptors such as bisphenols, can lead to and be the explanation for idiopathic infertility. In our study, we assessed the effect of exposure to bisphenol S (BPS) via breast milk on the testicular tissue health of adult male mice. Lactating dams were exposed to BPS through drinking water (0.216 ng g bw/day and 21.6 ng g bw/day) from post-natal day 0-15. Although there was no significant difference in testicular histopathology between the control and experimental groups, we observed an increase in the number of tight and gap junctions in the blood-testis barrier (BTB) of adult mice after lactation BPS exposure. Moreover, there was an increase in oxidative stress markers in adult testicular tissue of mice exposed via breast milk. Our lactation model indicates that breast milk is a route of exposure to an endocrine disruptor that can be responsible for idiopathic male infertility through the damage of the BTB and weakening of oxidative stress resistance in adulthood.

Nursing Exposure to Bisphenols as a Cause of Male Idiopathic Infertility

Idiopathic infertility is a serious problem, which can be caused and explained by exposure to endocrine disruptors, such as bisphenols. In our study, we studied transactional exposure to bisphenol and its effects on newborn male mice throughout their reproductive life. Newborn male mice were exposed to bisphenol S and bisphenol F through maternal milk from post-natal day 0 to post-natal day 15 at concentrations of 0.1 ng.g/bw/day and 10 ng.g/bw/day, respectively. Although there were minimal differences between the control and experimental groups in testicular tissue quality and spermatozoa quality, we discovered an interesting influence on early embryonic development. Moderate doses of bisphenol negatively affected cleavage of the early embryo and subsequently, the blastocyst rate, as well as the number of blastomeres per blastocyst. In our study, we focused on correlations between particular stages from spermatogenesis to blastocyst development. We followed epigenetic changes such as dimethylation of histone H3 and phosphorylation of histone H2 from germ cells to blastocysts; we discovered the transfer of DNA double-strand breaks through the paternal pronucleus from spermatozoa to blastomeres in the blastocyst. We elucidated the impact of sperm DNA damage on early embryonic development, and our results indicate that idiopathic infertility in adulthood may have causes related to the perinatal period.

Low doses of Bisphenol S affect post-translational modifications of sperm proteins in male mice

BACKGROUND

Bisphenol S (BPS) is increasingly used as a replacement for bisphenol A in the manufacture of products containing polycarbonates and epoxy resins. However, further studies of BPS exposure are needed for the assessment of health risks to humans. In this study we assessed the potential harmfulness of low-dose BPS on reproduction in male mice.

METHODS

To simulate human exposure under experimental conditions, 8-week-old outbred ICR male mice received 8 weeks of drinking water containing a broad range of BPS doses [0.001, 1.0, or 100 μg/kg body weight (bw)/day, BPS1-3] or vehicle control. Mice were sacrificed and testicular tissue taken for histological analysis and protein identification by nano-liquid chromatography/mass spectrometry (MS) and sperm collected for immunodetection of acetylated lysine and phosphorylated tyrosine followed by protein characterisation using matrix-assisted laser desorption ionisation time-of-flight MS (MALDI-TOF MS).

RESULTS

The results indicate that compared to vehicle, 100 μg/kg/day exposure (BPS3) leads to 1) significant histopathology in testicular tissue; and, 2) higher levels of the histone protein γH2AX, a reliable marker of DNA damage. There were fewer mature spermatozoa in the germ layer in the experimental group treated with 1 μg/kg bw (BPS2). Finally, western blot and MALDI-TOF MS studies showed significant alterations in the sperm acetylome and phosphorylome in mice treated with the lowest exposure (0.001 μg/kg/day; BPS1), although the dose is several times lower than what has been published so far.

CONCLUSIONS

In summary, this range of qualitative and quantitative findings in young male mice raise the possibility that very low doses of BPS may impair mammalian reproduction through epigenetic modifications of sperm proteins.

Cadmium-induced toxicity increases prolyl endopeptidase (PREP) expression in the rat testis

During the differentiation of the male gamete, there is a massive remodeling in the shape and architecture of all the cells of the seminiferous epithelium. The cytoskeleton, as well as many associated proteins with it, plays a pivotal role in this process. The testis is particularly susceptible to environmental pollutant, which can lead to injury and impairment of normal spermatozoa production. Cadmium (Cd) is one of the major chemical environmental toxicants in economically developed countries. Food and cigarettes are the main sources of exposure to this element. Here, the protective role of zinc (Zn) to prevent the testicular toxicity in male adult rats after prenatal and during lactation exposure to Cd has been assessed. Altered testicular histology at the interstitial and germinal levels was found, whereas Zn supply completely corrected Cd toxicity. Moreover, the effects of these metals on the testicular expression and localization of the protease prolyl endopeptidase (PREP) were evaluated. Interestingly, the results showed an increase of PREP messenger RNA and protein. Data were corroborated by immunofluorescence. This study raises the possibility of using PREP as a new fertility marker.

Early-Life Exposure to Cadmium Triggers Distinct Zn-Dependent Protein Expression Patterns and Impairs Brain Development

The objective of this study was to determine if the brain development impairment induced by early-life exposure to cadmium (Cd) could result from changes in the expression pattern of distinct zinc (Zn)-dependent proteins. For this purpose, adult female rats receiving either tap water, Cd, Zn, or Cd + Zn in their drinking water during gestation and lactation periods were used. After birth, the male offspring were screened for locomotors and sensorial defects. At postnatal day 21 (PND 21), the male pups were sacrificed and their brains, liver, and plasma were taken for chemical, biochemical, and molecular analyses. Our results show that exposure to Cd significantly increased the metal accumulation and decreased Zn concentrations in the brain of male pups from Cd-treated mothers. Besides, Cd exposure reduced significantly the locomotor activity of the offspring in open-field test, the body weight, and the cranio-caudal length at PND21. Insulin-like growth factor-I (IGF-1) levels in the plasma and liver were also decreased in male pups from Cd-treated mothers. Cd-induced brain development disruption was accompanied by a significant increase of the superoxide dismutase (SOD) activity, induction of the metallothionein (MT) synthesis, and, at the molecular level, by an upregulation of Zrt-,Irt-related protein 6 (ZIP6) gene and a significant downregulation of the expression of the Zn transporter 3 (ZnT3) and brain-derived neurotrophic factor (BDNF) genes in the brain. No significant changes on the expression of genes encoding other Zn-dependent proteins and factors such as ZnT1, ZIP12, NF-κB, and Zif268. Interestingly, Zn supplementation provided a total or partial correction of the changes induced by the Cd exposure. These data indicated that changes in expression of ZnT3 and ZIP6 as well as alteration of other transcription factors, such as BDNF, or Zn-dependent proteins, such as SOD and MTs, in response to Cd exposure might be an underlying mechanism of Cd-induced brain development impairment.

Disruption of the zinc metabolism in rat fœtal brain after prenatal exposure to cadmium

This study was carried out to investigate the effects of maternal Cd and/or Zn exposure on some parameters of Zn metabolism in fetal brain of Wistar rats. Thus, female controls and other exposed by the oral route during the gestation period to Cd (50 mg CdCl2/L) and/or Zn (ZnCl2 60 mg/L) were used. The male fetuses at age 20 days of gestation (GD20) were sacrificed and their brains were taken for histological, chemical and molecular analysis. Zn depletion was observed in the brains of fetuses issued from mothers exposed to Cd. Histological analysis showed that Cd exposure induces pyknosis in cortical region and CA1 region of the hippocampus compared to controls. Under Cd exposure, we noted an overexpression of the genes coding for membrane transporter involved in the intracellular incorporation of Zn (ZIP6) associated with inhibition of that encoding the transporters involved in the output of the Zn into the extracellular medium (ZnT1 and ZnT3). A decrease in the expression of the gene encoding the neuro-trophic factor (BDNF) associated with overexpression of the encoding the metal regulatory transcription factor 1 (MTF1), factor involved in the homeostasis of Zn, was also noted in Cd group. Interestingly, Zn supply provided a total or partial restauration of the changes induced by the Cd exposure. The depletion of brain Zn contents as well as the modification of the profile of expression of genes encoding membrane Zn transporters, suggest that the toxicity of Cd observed in fetal brain level are mediated, in part, by impairment of Zn metabolism.

Involvement of Zn Depletion in Cd-Induced Toxicity on Prenatal Bone Formation in Rat

This study explored the potential toxicity of Cd on the Zn bone depletion in prenatal bone formation. Female rats received either tap water, Cd, Zn, or Cd + Zn in their drinking water during gestation, and some markers of bone formation were studied in their fetuses removed at the 20th day of pregnancy (GD20). Cd exposure induced maternal hypozincemia and Zn depletion in the femur of the fetuses. A striking inhibition of bone formation in fetuses, expressed by decreases in femur length, width, and area, by the shortening of diaphysis, and by a decrease in length and area of distal and proximal proliferative zones, was observed in fetuses from Cd-exposed mothers. At the molecular level, Cd caused upregulation of MT-1 and ZIP2 genes and significantly depressed the expression of the ZnT5, colα1, osteocalcin, and ALP genes in the femur. Interestingly, Zn treatment ameliorated the Cd-induced maternal hypozincemia and femoral changes and partially restored the normal histomorphometry of the femur. These results suggest that the observed toxic effects of Cd are, at least in part, mediated by the disruption of maternal Zn metabolism during pregnancy leading to Zn depletion and thus to perturbation of prenatal bone formation.

Protective role of zinc against the toxicity induced by exposure to cadmium during gestation and lactation on testis development

To assess the effects of exposure to Cd and Zn on rat testicular development, offspring, from mothers receiving either tap water, Cd, Zn or Cd+Zn during gestation and lactation periods, were observed on gestational day (GD) 20 and on postnatal days (PND) 12, 21 and 35. During gestation, Cd induced maternal hypozincemia and less transfer of Zn to the fetus. During lactation, progressive Cd accumulation and Zn depletion in testis at PND12 and PND21 were noted. An increase of abnormal seminiferous tubules and a decrease in testis weight and plasmatic testosterone concentration were also observed at PND21 and PND35 respectively. Interestingly, Zn supply induced a significant protection against Cd toxicity. These results suggest that the toxic effects of Cd observed during development are mediated by the disruption of Zn metabolism, which is established in mothers during pregnancy causing Zn deficiency in fetuses and continues to become more pronounced during lactation.

Changes of the mRNA expression pattern of Zn transporters: a probable mechanism for cadmium retention and zinc redistribution in the suckling rat tissues

The present study was conducted to provide potential mechanism that may be responsible for Cd retention and Cd-induced Zn redistribution in tissues of suckling rat. For this purpose, suckling rats from mother receiving either tap water, Cd, or Cd + Zn during lactation period were sacrificed on postnatal day (PND) 14 and PND 21 for performing chemical and molecular analysis. Our results show that Cd exposure, although it does not affect the milk consumption, it clearly alters the lactational transfer, absorption, and distribution of Zn in the suckling rat organism. At the molecular level, Cd caused upregulation of ZIP 3, ZIP 4, and ZIP 8 gene expressions in the mammary gland of mothers rats and in the intestine of their pups but decreased the expression of ZnT 2 and ZnT 4 only in the mammary tissue at PND 14 and PND 21. Zn supply reversed the Cd-induced decrease in the neonatal Zn apparent absorption and restores the gastrointestinal, brain, and plasma levels of this essential element in the suckling rat organism at PND 14 and PND 21. Also, with this treatment, the gene expressions of ZnT 1 in the mammary gland and ZnT 4 in the neonatal intestine were found to be upregulated at PND 21. Furthermore, our results show that Cd or Cd + Zn treatment increase the neonatal hepatic MTs accumulation at PND 14 only. These results imply that the downregulation of ZnT as well as the overexpression of ZIP transporters, in responses to the Zn depletion induced by Cd in the tissues of lactating rat and their offspring, play a major role in Cd accumulation and Zn redistribution in tissues of suckling rat.

New bridged oligofuran for optoelectronic applications

Based on density functional theory (DFT) calculations, we have investigated the structural and optoelectronic properties of oligofuran (OFu)-bridged systems via useful electron donating groups (>S, >CH2, >SiH2 and >NH) and electron accepting ones (>CC(CN)2, >CO, >CS and >CCH2). The results were then discussed and compared with those obtained with the correspondingunbridged form. It was found that the optical band gap of OFu decreases significantly when it is bridged by >NH group arranged through an alternating way with >CS or >CC(CN)2 group, which gives bridged polyfuran (PFu) with desirable opto-electronic properties. Further, an intra-molecular charge transfer for the systems was undertaken in support of time-dependent DFT (TD-DFT) and semi-empirical ZINDO calculations. In this frame, we have shown that >CC(CN)2 and >S bridging groups leads to a new oligomer possessing favorable optoelectronic parameter for its use as an active layer in organic photovoltaic cells.

Theoretical study of phenylene-thiophene oligomers: structure-properties relationship

Theoretical results including geometrical characteristics, electronic structures, photophysical parameters (lowest excitation energies, electron affinities (EAs), ionization potentials (IPs), maximum of absorption and emission) and vibrational modes of some new oligomers, based on phenylene-thiophene motives, are investigated using Density Functional Theory DFT/B3LYP/6-31G(d) approach. The electronic and optical properties of phenylene-based derivatives can be tuned through the insertion of thiophene in the main oligomers backbone as well as the addition of alkoxy-substituent groups on 2 and 5 positions on phenylene groups. It can be noticed, that different conformational behaviors and steric effects take place. Then, an increase in conjugation length induces a decrease in the gaps energy and a bathochromic shift of absorption/emission spectra. Based on these computed results, which are consistent with the available experimental data, the correlation structure-properties is better understood, where these nanostructures show a great potential for opto-electronic devices.