The NcZrg-17 gene of Neurospora crassa encodes a cation diffusion facilitator transporter required for vegetative development, tolerance to endoplasmic reticulum stress and cellulose degradation under low zinc conditions

Compound Tongluo Decoction inhibits endoplasmic reticulum stress-induced ferroptosis and promoted angiogenesis by activating the Sonic Hedgehog pathway in cerebral infarction

ETHNOPHARMACOLOGICAL RELEVANCE

Cerebral infarction is one of the most common types of cerebrovascular diseases that threaten people's health. Compound Tongluo Decoction (CTLD), a traditional Chinese medicine formula, has various pharmacological activities, including the alleviation of cerebral infarction symptoms.

AIM OF THE STUDY

This study aims to explore the potential mechanism by which CTLD alleviates cerebral infarction.

MATERIAL AND METHODS

Middle cerebral artery occlusion (MCAO) rat model and oxygen-glucose deprivation and reperfusion (OGD/R) cell model were established for research. The expression of proteins related to endoplasmic reticulum (ER) stress, ferroptosis, Sonic Hedgehog (SHH) pathway and angiogenesis was analyzed by Western blot analysis. The expression of CD31 was detected by immunofluorescence to investigate angiogenesis. In addition, the expression of GRP78 and XBP-1 in brain tissues was investigated by immunohistochemistry. With the application of Prussian blue staining, iron deposition in brain tissue was detected. The levels of reactive oxygen species (ROS), malondialdehyde (MDA), superoxide dismutase (SOD) were detected using ELISA kits. The angiogenesis was analyzed by tube formation assay.

RESULTS

The results presented in this research showed that CTLD and 4-phenyl butyric acid (4-PBA; the inhibitor of ER stress) could alleviate cerebral infarction. Mechanistically, CTLD and 4-PBA rescued ER stress and ferroptosis, but promoted SHH signaling in rats with cerebral infarction. In addition, cerebral infarction exhibited a high level of angiogenesis, which was aggravated by CTLD but suppressed by 4-PBA. Furthermore, CTLD inhibited ER stress and ferroptosis, but promoted SHH signaling and angiogenesis in OGD/R-induced PC12 cells, which was partly abolished by SANT-1, an antagonist of SHH signaling.

CONCLUSION

In conclusion, this study revealed that CTLD might inhibit ferroptosis induced by endoplasmic reticulum stress and promote angiogenesis by activating the Sonic Hedgehog pathway in rats with cerebral infarction.

Regulatory microRNAs and vascular cognitive impairment and dementia

Vascular cognitive impairment and dementia (VCID) is defined as a progressive dementia disease related to cerebrovascular injury and often occurs in aged populations. Despite decades of research, effective treatment for VCID is still absent. The pathological processes of VCID are mediated by the molecular mechanisms that are partly modulated at the post-transcriptional level. As small endogenous non-coding RNAs, microRNAs (miRs) can regulate target gene expression through post-transcriptional gene silencing. miRs have been reported to play an important role in the pathology of VCID and have recently been suggested as potential novel pharmacological targets for the development of new diagnosis and treatment strategies in VCID. In this review, we summarize the current understanding of VCID, the possible role of miRs in the regulation of VCID and attempt to envision future therapeutic strategies. Since manipulation of miR levels by either pharmacological or genetic approaches has shown therapeutic effects in experimental VCID models, we also emphasize the potential therapeutic value of miRs in clinical settings.

Two dominant selectable markers for genetic manipulation in Neurospora crassa

Neurospora crassa is an excellent model fungus for studies on molecular genetics, biochemistry, physiology, and molecular cell biology. Along with the rapid progress of Neurospora research, new tools facilitating more efficient and accurate genetic analysis are in high demand. Here, we tested whether the dominant selective makers widely used in yeasts are applicable in N. crassa. Among them, we found that the strains of N. crassa are sensitive to the aminoglycoside antibiotics, G418 and nourseothricin. 1000 μg/mL of G418 or 50 μg/mL of nourseothricin is sufficient to inhibit Neurospora growth completely. When the neomycin phosphotransferase gene (neo) used in mammalian cells is expressed, N. crassa shows potent resistance to G418. This establishes G418-resistant marker as a dominant selectable marker to use in N. crassa. Similarly, when the nourseothricin acetyltransferase gene (nat) from Streptomyces noursei is induced by qa-2 promoter in the presence of quinic acid (QA), N. crassa shows potent resistance to nourseothricin. When nat is constitutively expressed by full-length or truncated versions of the promoter from the N. crassa cfp gene (NCU02193), or by the trpC promoter of Aspergillus nidulans, the growth of N. crassa in the presence of nourseothricin is proportional to the expression levels of Nat. Finally, these two markers are used to knock-out wc-2 or al-1 gene from the N. crassa genome. The successful development of these two markers in this study expands the toolbox for N. crassa and very likely for other filamentous fungi as well.

Zinc homeostasis in the secretory pathway in yeast

It is estimated that up to 10% of proteins in eukaryotes require zinc for their function. Although the majority of these proteins are located in the nucleus and cytosol, a small subset is secreted from cells or is located within an intracellular compartment. As many of these compartmentalized metalloproteins fold to their native state and bind their zinc cofactor inside an organelle, cells require mechanisms to maintain supply of zinc to these compartments even under conditions of zinc deficiency. At the same time, intracellular compartments can also be the site for storing zinc ions, which then can be mobilized when needed. In this review, we highlight insight that has been obtained from yeast models about how zinc homeostasis is maintained in the secretory pathway and vacuole.

Disturbance in biosynthesis of arachidonic acid impairs the sexual development of the onion blight pathogen Stemphylium eturmiunum

The formation of sexual fruiting bodies for plant pathogenic fungi is a key strategy to propagate their progenies upon environmental stresses. Stemphylium eturmiunum is an opportunistic plant pathogen fungus causing blight in onion. This self-fertilizing filamentous ascomycete persists in the soil by forming pseudothecia, the sexual fruiting body which helps the fungus survive in harsh environments. However, the regulatory mechanism of pseudothecial formation remains unknown. To uncover the mechanism for pseudothecial formation so as to find a practical measure to control the propagation of this onion pathogen, we tentatively used DNA methyltransferase inhibitor 5-azacytidine (5-AC) to treat S. eturmiunum. 5-AC treatment silenced the gene-encoding monoacylglycerol lipase (magl) concomitant with the presence of the inheritable fluffy phenotype and defectiveness in pseudothecial development. Moreover, the silence of magl also resulted in a reduction of arachidonic acid (AA) formation from 27 ± 3.1 µg/g to 9.5 ± 1.5 µg/g. To correlate the biosynthesis of AA and pseudothecial formation, we created magl knockdown and overexpression strains. Knockdown of magl reduced AA to 11 ± 2.4 µg/g, which subsequently disabled pseudothecial formation. In parallel, overexpression of magl increased AA to 37 ± 3.4 µg/g, which also impaired pseudothecial formation. Furthermore, exogenous addition of AA to the culture of magl-silenced or magl knockdown strains rescued the pseudothecial formation but failed in the gpr1 knockdown strain of S. eturmiunum, which implicates the involvement of AA in signal transduction via a putative G protein-coupled receptor 1. Thus, AA at a cellular level of 27 ± 3.1 µg/g is essential for sexual development of S. eturmiunum. Disturbance in the biosynthesis of AA by up- and down-regulating the expression of magl disables the pseudothecial development. The specific requirement for AA in pseudothecial development by S. eturmiunum provides a hint to curb this onion pathogen: to impede pseudothecial formation by application of AA.