Molecular mimicry and COVID-19: Potential implications for global fertility.

There has been a concerning increase in the incidence of autoimmune diseases following SARS-CoV-2 infection, with molecular mimicry proposed as a potential mechanism. Our study identified nine fertility-associated proteins (AMH, BMP2, CUBN, DNER, ERCC1, KASH5, MSLN, TPO, and ZP3) that exhibit potential molecular mimicry with MHC-II epitopes of SARS-CoV-2 proteins (N, ORF1A, ORF1AB, and S). We screened for epitopes based on in silico binding using DR-, DQ-, and DP-haplotypes that predispose susceptible individuals to autoimmune diseases. Our systematic analysis revealed that 41 countries with population coverage of over 50% had a pre-COVID pandemic total fertility rate of less than 2.1 births per woman. With over 761 million people from 229 countries and territories infected since December 2019, there may be a potential for a foreseeable negative effect on fertility in specific countries, particularly in high-income economies experiencing rapid demographic changes.

Ecological and health risks from heavy metal sources surrounding an abandoned mercury mine in the island paradise of Palawan, Philippines.

A recent survey that determined heavy metal concentrations in an abandoned Hg mine in Palawan, Philippines, found the occurrence of Hg with As, Ba, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Sb, Tl, V, and Zn. While the Hg originated from the mine waste calcines, the critical knowledge about the origin of the other heavy metals remains unknown. This study assessed the ecological and health risks from heavy metal pollution surrounding the abandoned Hg mine. Principal component analysis (PCA) showed that the abandoned mine and natural sources (i.e., local geology) are the two main contributors of heavy metal pollution. Historically, the mine waste calcines (retorted ore) were used as construction material for the wharf and as land filler for the adjacent communities. There is highly strong ecological risk associated with the heavy metals: Ni, Hg, Cr, and Mn contribute 44.3%, 29.5%, 10.7%, and 8.9% to the potential ecological risk index (RI), respectively. Hazard index (HI) exceeded 1 for both adults and children in all the sampling locations, implying non-carcinogenic adverse effects. The total cancer risk over a lifetime (LCR) also exceeded the threshold limit of 10-4 for both adults and children, contributed mainly by Cr (91.8%) and As (8.1%). By combining the results of the PCA and risk assessments, a clear link between heavy metal source apportionment to ecological and health risks was established. It was estimated that the abandoned mine contributed to most of the ecological and health risks for people living near the wharf that was built using the calcine, as well as the nearby Honda Bay. The findings of this study are expected to help policy makers develop regulations that will safeguard the ecosystem and the general public from the damaging impacts of heavy metals from the abandoned mine.

Transport of toxic metals in the bottom sediments and health risk assessment of Corbicula fluminea (Asiatic clam) collected from Laguna de Bay, Philippines.

Laguna de Bay, the 3rd largest lake in Southeast Asia, is the most significant source of freshwater fish in the Philippines. With decades of unregulated discharge of industrial, domestic, and agricultural wastewaters into the lake, this study investigates the apportionment of heavy metals from the bottom sediments and its impact on the toxicity of Corbicula fluminea (Asiatic clam), a popular food item in the markets. The sediment samples from the western part of the lake contained higher Cd, Cu, Pb, and Zn and lower As and Cr concentrations compared to the eastern part. There were positive correlations for As, Cr, Cu, Pb, and Zn and negative correlations for Cd and Ni concentrations noted between sediments and C. fluminea. Human health risk associated with the consumption of C. fluminea collected from Laguna de Bay was attributed to the following heavy metals: Cu > As > Zn > Cd > Pb > Cr > Ni. Interestingly, the observed trend in toxicities of the shellfish was consistent with the transport phenomenon of heavy metals facilitated by the counterclockwise direction of the bottom current. This study strongly suggests the re-evaluation of the waste management plan in the industrial zones and policies regulating the sale of the shellfish harvest.

Analysis of the copper removal kinetics of the Philippine giant bamboo (Dendrocalamus asper) in hydroponics.

Copper is the third most utilized metal and is a versatile resource with multiple beneficial uses, but it may also become toxic to aquatic life in excess amount. Thus, there is a need to develop methods to reduce the copper contamination in the environment, particularly in bodies of water. Phytoremediation using Dendrocalamus asper may offer an environment-benign and potentially effective method for copper removal though its effectiveness may take several years to materialize for this technology to become cost-effective. By growing D. asper in synthesized contaminated water and analyzing the change in the copper content of the substrate via atomic absorption spectrophotometry, the removal was found to be optimal at 20 ppm Cu and pH 5. The rate of removal was found to have an order of 2.71 and a kinetic constant of 0.0013 ppm-1.71 day-1. With this, it may be possible to estimate the treatment length of phytoremediation given an initial level of copper contamination and a target concentration.

AtHDA15 binds directly to COP1 positively regulating photomorphogenesis.

Reversible histone acetylation and deacetylation play crucial roles in modulating light-regulated gene expression during seedling development. However, it remains largely unknown how histone-modifying enzymes interpose within the molecular framework of light signaling network. In this study, we show that AtHDA15 positively regulates photomorphogenesis by directly binding to COP1, a master regulator in the repression of photomorphogenesis. hda15 T-DNA knock-out and RNAi lines exhibited light hyposensitivity with reduced HY5 and PIF3 protein levels leading to long hypocotyl phenotypes in the dark while its overexpression leads to increased HY5 concentrations and short hypocotyl phenotypes. In vivo and in vitro binding assays show that HDA15 directly interacts with COP1 inside the nucleus modulating COP1's repressive activities. As COP1 is established to act within the nucleus to regulate specific transcription factors associated with growth and development in skotomorphogenesis, the direct binding by HDA15 is predicted to abrogate activities of COP1 in the presence of light and modulate its repressive activities in the dark. Our results append the mounting evidence for the role of HDACs in post-translational regulation in addition to their well-known histone modifying functions.

Druggability of mortalin for cancer and neuro-degenerative disorders.

Mortalin is a member of Hsp70 family of stress chaperones. It was first identified as a protein involved in the senescence of mouse cells. Genetic studies revealed that there are two mouse mortalin alleles coding for two proteins (mot-1 and mot-2) that differ in only two amino acids in the carboxy-terminus, but have contrasting activities. Whereas mot-1 accelerated senescence, mot-2 extended the lifespan of mouse cells in culture. In human cells, only one kind of mortalin protein has been identified so far and is shown to be functionally equivalent to mouse mot-2. Whereas mortalin is enriched in cancer cells and contributes to carcinogenesis, the old age brain disorders show its deficiency. As we demystify its deux de machina, accumulating evidence reveal that mortalin may be "druggable" bidirectionally to either treat cancer or neuro-degenerative disorders.

Mouse Homologue of the Schizophrenia Susceptibility Gene ZNF804A as a Target of Hoxc8.

Using a ChIP-cloning technique, we identified a Zinc finger protein 804a (Zfp804a) as one of the putative Hoxc8 downstream target genes. We confirmed binding of Hoxc8 to an intronic region of Zfp804a by ChIP-PCR in F9 cells as well as in mouse embryos. Hoxc8 upregulated Zfp804a mRNA levels and augmented minimal promoter activity in vitro. In E11.5 mouse embryos, Zfp804a and Hoxc8 were coexpressed. Recent genome-wide studies identified Zfp804a (or ZNF804A in humans) as a plausible marker for schizophrenia, leading us to hypothesize that this embryogenic regulatory control might also exert influence in development of complex traits such as psychosis.

Hoxc8 represses BMP-induced expression of Smad6.

Proper regulation of bone morphogenetic protein (BMP) signaling is critical for correct patterning and morphogenesis of various tissues and organs. A well known feedback mechanism is a BMP-mediated induction of Smad6, an inhibitor of BMP signaling. Hoxc8, one of the Hox family transcription factors, has also been shown to negatively regulate BMP-mediated gene expression. Here we add another level of Hoxc8 regulation on BMP signaling. Our results show that Hoxc8, when over-expressed in C3H10T1/2 or C2C12 cells, suppressed basal Smad6 promoter activity and its mRNA expression. Activation of Smad6 transcription either by BMP2 treatment or Smad1 over-expression was also abolished by Hoxc8. When chromatin was precipitated from mouse embryos with anti-Smad1 or anti-Hoxc8 antibody, Smad6 promoter sequence was enriched, suggesting that Hoxc8 proteins make complexes with Smad1 in the Smad6 promoter region. Yet, a lack of Hox binding motifs in the Smad6 promoter sequence suggests that instead of directly binding to the DNA, Hoxc8 may regulate Smad6 expression via an indirect mechanism. Our results suggest that the Smad6-mediated negative feedback mechanism on BMP signaling may be balanced by the repression of Smad6 expression by Hoxc8.

The versatile stress protein mortalin as a chaperone therapeutic agent.

Age- and stress-induced modulations in chaperone systems result in "chaperono-deficiency" or "chaperon-opulence". Development of modulators, of chaperone function has therefore, become an emerging field in drug development and discovery. This mini-review summarizes (i) the events leading to identification of an Hsp70 family stress chaperone, mortalin, (ii) experimental evidence to its role in old age diseases and cancer, and (iii) proposes it as a chaperono-therapeutic agent. As post-translational modifications and expression changes in mortalin are being explored as a biomarker for cancer, cardiovascular diseases and neurodegeneration, we discuss here how the current tools used in studying mortalin (e.g. antibodies, peptides, ribozymes, antisense and siRNA, recombinant proteins and small molecules etc.) could be creatively applied in a clinical setting to manage stress and to treat various chaperone-based maladies or "chaperonopathies".

From proliferative to neurological role of an hsp70 stress chaperone, mortalin.

Although the brain makes up approximately 2% of a person's body weight, it consumes more than 15% of total cardiac output and has a per capita caloric requirement of 10 times more than the rest of the body. Such continuous metabolic demand that supports the generation of action potentials in neuronal cells relies on the mitochondria, the main organelle for power generation. The phenomenon of mitochondrial biogenesis, although has long been a neglected theme in neurobiology, can be regarded as critical to brain physiology. The present review emphasizes the role of a key molecular player of mitochondrial biogenesis, the mortalin/mthsp70. Brain mortalin is discussed in relation to its aptitude to impact on mitochondrial function and homeostasis, to its interfacing energy metabolic functions with synaptic plasticity, and to its modulation of brain aging via the cellular senescence pathways. Recently, this chaperone has been implicated in Alzheimer's (AD) and Parkinson's (PD) diseases, with proteomic studies consistently identifying oxidatively-damaged mortalin as potential biomarker. Hence, it is possible that mitochondrial dysfunction coincides with the collapse in the mitochondrial chaperone network that aim not only to import, sort and maintain integrity of protein components within the mitochondria, but also to act as buffer to the molecular heterogeneity of damaged and aging mitochondrial proteins within a ROS-rich microenvironment. Inversely, it may also seem that vulnerability to mitochondrial dysfunction could be precipitated by malevolent (anti-chaperone) gain-of-function of a 'sick mortalin'.

Extract from Acanthopanax senticosus harms (Siberian ginseng) activates NTS and SON/PVN in the rat brain.

The extract of the stem bark of Siberian ginseng, Acanthopanax senticosus Harms (ASH), is believed to play a body-coping role in stress through a brain noradrenergic mechanism. The present study was carried out to investigate the effect of ASH on the neuronal activation patterns of c-Fos expression in the rat brain. With ASH administration, c-Fos accumulated in both the supraoptic nuclei (SON) and paraventricular nuclei (PVN), which regulate stress response. Only the caudal regions in the nucleus of the solitary tract (NTS), a locus innervating both the SON and PVN, were activated. Such a neuro-anatomical pattern associated with ASH suggests the possible involvement of these stress-related brain loci.

Enhancing effect of cerebral blood volume by mild exercise in healthy young men: a near-infrared spectroscopy study.

A mechanism by which exercise improves brain function may be attributed to increase in cerebral blood volume (CBV) with physical activity. However, the exact exercise intensity that influences CBV is still uncertain. To clarify this issue, 10 healthy young male participants were asked to perform a graded cycling exercise to the point of exhaustion while their prefrontal cortex CBVs are being monitored using near-infrared spectroscopy. Overall responsive cerebral oxygenation showed a non-linear pattern with three distinct phases. The CBV-threshold (CBVT), an event where rapid oxygenation takes place, occurred at approximately 42% of the V O2max. The CBVT preceded the lactate threshold (LT), which was at approximately 55% of the V O2max. The V O2max was not predictive of the CBVT in among the subjects. Our results indicate that oxygenation of the prefrontal cortex increases during graded cycling even at exercise intensities below the LT, suggesting the potential role of mild exercise in enhancing CBV.

Merger of ayurveda and tissue culture-based functional genomics: inspirations from systems biology.

Ayurveda is one of the ancient systems of health care of Indian origin. Roughly translated into "Knowledge of life", it is based on the use of natural herbs and herb products for therapeutic measures to boost physical, mental, social and spiritual harmony and improve quality of life. Although sheltered with long history and high trust, ayurveda principles have not entered laboratories and only a handful of studies have identified pure components and molecular pathways for its life-enhancing effects. In the post-genomic era, genome-wide functional screenings for targets for diseases is the most recent and practical approach. We illustrate here the merger of ayurveda and functional genomics in a systems biology scenario that reveals the pathway analysis of crude and active components and inspire ayurveda practice for health benefits, disease prevention and therapeutics.

Glycerol stimulates innate chaperoning, proteasomal and stress-resistance functions: implications for geronto-manipulation.

Aging is associated with accumulation of toxic intracellular and extracellular protein aggregates. Cells manage "aged" proteins by mobilizing their molecular chaperones or heat shock proteins that are also considered as determinants of lifespan in diverse species. In this study, we tested whether an exogenous addition of the non-toxic chemical chaperone 'glycerol' could elicit stress and geronto-protective activities. We found that glycerol enhanced chaperoning of heat-denatured proteins. In addition to stimulating proteasome activity, glycerol led to an increased expression of the stress chaperone 'mortalin' and decreased p53 function in human cells. Glycerol-fed worms exhibited thermo-tolerance and lower level of age-associated auto-fluorescence. Through the combined stimulation of the proteasome and chaperoning activities of mortalin, in particular, glycerol treatment resulted in increased survival and fitness against oxidative- and heat-stress. These results may have significant implications in the use of glycerol as a candidate geronto-modulator in development of practical interventions for "healthy aging".

Functional significance of minor structural and expression changes in stress chaperone mortalin.

Mortalin is one of the highly conserved heat-shock chaperones. Some of the established features of mortalin include its various subcellular localizations, multiple binding partners, and differential subcellular distribution in normal and immortal cells. It inhibits nuclear translocation, transcriptional activation, and control of centrosome-duplication functions of p53. It also functions as an adaptive protein in a variety of stress-response mechanisms and contributes to human carcinogenesis. Interestingly, minor alterations in its structure and level of expression may lead to drastic biological consequences (for example, Myelodysplastic syndrome and old age pathologies, such as Alzheimer's and Parkinson's disease). Besides being validated as a reliable target for cancer therapy, mortalin also warrants attention from the perspectives of management of old-age diseases and healthy aging.

Use of ribozymes in cellular aging research.

Ribozymes are naturally-occurring catalytic RNAs from the viroid world and are being engineered in the laboratory to perform sequence-specific cleavage of a desired mRNA target. Since their Nobel Prize-winning discovery, there has been considerable interest in the utility of ribozymes as gene therapeutic agents to silence disease-causing genes. This technology is not perfect, but extensive efforts to improve upon natural design of ribozymes have enabled these RNA molecules to perform various tasks. In this chapter, we highlight the construction of two types of ribozymes: conventional and hybrid hammerhead ribozymes. The hybrid ribozyme described here is an improved version of the basic hammerhead motif with the following features: (a) the use of the RNA polymerase III (polIII) tRNAVal promoter to achieve a high level of transcription, (b) 5' linkage to the cloverleaf-shaped tRNAVal to enhance intracellular stability and cytoplasmic transport, and (c) a 3' end poly-(A) tail to act as a "molecular anchor" for endogenous RNA helicases endowing the ribozyme ability to disentangle higher-order structures of the target mRNA. Randomized hybrid ribozyme libraries have been used successfully for revelation of gene functions involved in metastasis, invasion, differentiation, apoptosis, endoplasmic reticulum stress and may be extended to gene functions involved in innate or induced cellular senescence of human cells.

BDNF induction with mild exercise in the rat hippocampus.

Although chronic voluntary physical activity has been shown to enhance hippocampal brain-derived neurotrophic factor (BDNF) expression in animals, the effects of forced exercise on a treadmill have not been fully investigated. We assessed induction of c-fos and BDNF expression with acute exercise at different running intensities. The mRNA for c-fos, a marker for neuronal activation, was up-regulated even under low-intensity running (15 m/min), although its induction appeared to be intensity dependent. On the other hand, increases in BDNF mRNA and protein were seen only at low-intensity running. At moderate-intensity running (25 m/min) which elevated blood lactate and corticosterone levels, induction of BDNF mRNA, but not its protein, was even depressed. Our study shows the first evidence that with an acute low-intensity exercise that is minimally stressful, hippocampal activation and BDNF expression can be achieved lending support to the idea that mild exercise could yield to greater benefits in hippocampal functions compared to the more strenuous forms.

Threshold-like pattern of neuronal activation in the hypothalamus during treadmill running: establishment of a minimum running stress (MRS) rat model.

Despite the indication that the hypothalamo-pituitary-adrenal (HPA) axis is activated during treadmill running, there have not been any studies focusing on the relationship between exercise intensity and region-specific neural activities in hypothalamus. To address this, rats were subjected to 30 min of running, either at middle (supra-LT, 25 m min(-1)) or low speeds (sub-LT, 15 m min(-1)), and c-Fos-(+) cells were counted and compared with control rats. Significant increases in blood glucose and lactate levels, and plasma ACTH and osmolality levels were observed during supra-LT running. Only supra-LT running significantly increased c-Fos induction in various hypothalamic regions, namely, the medial preoptic area (MPO), periventricular nucleus (Pe), suprachiasmatic nucleus (SCN), supraoptic nucleus (SON), parvocellular division of the paraventricular nucleus (pPVN), anterior hypothalamic area (AH), arcuate nucleus (ARC) and posterior hypothalamic nucleus (PH). However, sub-LT caused no effect on c-Fos accumulation. This indicates that the hypothalamus responds uniquely to running in a threshold-like pattern distinct from the speed-dependent pattern previously reported for the medulla oblongata [Ohiwa et al., 2006a,b]. In addition, these results showed a physiologic basis for mild exercise useful for establishing our minimum running stress (MRS) rat model, or the running conditions that minimize the activation of the HPA axis.

Stress chaperones, mortalin, and pex19p mediate 5-aza-2' deoxycytidine-induced senescence of cancer cells by DNA methylation-independent pathway.

DNA demethylating agents are used to reverse epigenetic silencing of tumor suppressors in cancer therapeutics. Understanding of the molecular and cellular factors involved in DNA demethylation-induced gene desilencing and senescence is still limited. We have tested the involvement of two stress chaperones, Pex19p and mortalin, in 5-Aza-2' deoxycytidine (5AZA-dC; DNA demethylating agent)-induced senescence. We found that the cells overexpressing these chaperones were highly sensitive to 5AZA-dC, and their partial silencing eliminated 5AZA-dC-induced senescence in human osteosarcoma cells. We demonstrate that these chaperones modulate the demethylation and chromatin remodeling-dependent (as accessed by p16(INK4A) expression) and remodeling-independent (such as activation of tumor suppressor p53 pathway) senescence response of cells. Furthermore, we found the direct interactions of 5AZA-dC with these chaperones that may alter their functions. We conclude that both mortalin and Pex19p are important mediators, prognostic indicators, and tailoring tools for 5AZA-dC-induced senescence in cancer cells.

Mortalin sensitizes human cancer cells to MKT-077-induced senescence.

Mortalin is a chaperone protein that functions in many cellular processes such as mitochondrial biogenesis, intracellular trafficking, cell proliferation and signaling. Its upregulation in many human cancers makes it a candidate target for therapeutic intervention by small molecule drugs. In continuation to our earlier studies showing mortalin as a cellular target of MKT-077, a mitochondrion-seeking delocalized cationic dye that causes selective death of cancer cells, in this work, we report that MKT-077 binds to the nucleotide-binding domain of mortalin, causes tertiary structural changes in the protein, inactivates its chaperone function, and induces senescence in human tumor cell lines. Interestingly, in tumor cells with elevated level of mortalin expression, fairly low drug doses were sufficient to induce senescence. Guided by molecular screening for mortalin in tumor cells, our results led to the idea that working at low doses of the drug could be an alternative senescence-inducing cancer therapeutic strategy that could, in theory, avoid renal toxicities responsible for the abortion of MKT-077 clinical trials. Our work may likely translate to a re-appraisal of the therapeutic benefits of low doses of several classes of anti-tumor drugs, even of those that had been discontinued due to adverse effects.