Circular RNA (circRNA) is widely expressed in eukaryotic cells, which originates from protein-coding genes. It has been found that circRNAs can play an important regulatory role in gene expression through a mode of action such as miRNA “sponge”, having organ-specific expression profiles. There is increasing evidence that circRNAs may be potential disease markers and therapeutic targets. In this paper, the research progress of circRNAs in diseases in recent years is reviewed, including the following aspects: (1) basic characteristics of circRNAs; (2) synthetic regulation of circRNAs; (3) regulation of circular RNA-mediated gene expression mechanisms; (4) the role of circRNAs in neoplastic diseases; (5) the role of circRNAs in infection-related immune diseases; (6) the role of circRNAs in cardiovascular diseases. The future research trend in this field is also predicted.
With the increasing incidence of psoriasis in recent years, research on the etiology of psoriasis has become deepgoing. The study on the correlation between fungal infection and psoriasis began in the 19th century, and it was believed that Malassezia infection might be the pathogenesis of psoriasis, and the fungus was closely related to the occurrence and development of psoriasis. Some studies indicated that Candida albicans induced or aggravated psoriasis through superantigen. However, relying on the characteristics of increasing IL-17, psoriasis patients can resist microbial infection to a certain extent. The relationship between fungal infection and psoriasis is not conclusive yet. With the deepening research, fungal infection is still regarded as one of the factors that can not be ignored in inducing or aggravating psoriasis.
At present, fungal infection is more and more common and serious, but the clinical usage of antifungal drugs is limited by their toxic and side effects, which may be valuable in use in the future. This paper reviews the main mechanisms of antifungal effects of Chinese medicine ingredients, concerning interfering substance transport, yeast-to-hypha transition, host immunity, redox and others, for purposes of providing reference material for application of Chinese medicine in antifungal treatment.
Sporothrix complex is a dimorphic fungi with worldwide distribution, causing chronic deep infections in humans and animals. There are differences in virulence, transmission route and drug sensitivity among strains from different regions. As a zoonotic disease, the incidence of sporotrichosis increased year by year, and outbreaks of the disease appeared on many occasions. Molecular typing is not only a powerful method of identifying the source of infection and the route of transmission, but also preventing and controlling the epidemic. It is also helpful to understand the correlation between the genotype and phenotype of Sporothrix, and is of great significance in studying pathogenic mechanism and clinical diagnosis and treatment of the disease. In this paper, the genotyping studies for Sporothrix complex were reviewed.
Recent research has shown that epidermal resident fungi play an important role in many allergic skin diseases through affecting skin barrier, regulating skin immune balance and mediating inflammatory responses. In this review, correlation between skin fungi and common allergic skin diseases, such as atopic dermatitis, seborrheic dermatitis, dermatophytid and urticaria etc. are described. The most common methods for the detection of fungal allergens in clinic are also reviewed.
The morbidity and mortality of invasive fungal infections (IFIs) are on the increase in recent several years owing to the growing number of immunodeficient patients, and lead to a serious threat to human health. At present, triazoles (fluconazole), polyenes (amphotericin B) and echinocandins (caspofungin), as routine anti-IFIs drugs, are widely administrated in clinical practice. However, the present therapeutic regime in IFIs remains dismal despite decades of efforts in anti-IFIs drugs. Therefore, evaluating the correlation between frontier antifungal drugs and their effects on clinical phases were warranted. In this review, we present various therapeutic targets, including fungal cell wall, cell membrane, cell metabolism, and biological agents. CD101 and SCY-078 inhibiting glucan synthase, nikkomycins Z inhibiting chitin synthase, APX001 inhibiting GPI-anchored protein, VT-1161 and VT-1129 inhibiting fungal CYP51, CAmB disrupting cell membrane permeability, F901318 inhibiting pyrimidine synthesis, cell surface lectin-like sequence 3 protein vaccine (NDV-3) and antifungal infection antibody mycograb were also fully discussed. Besides, this article reviews the research progress of the anti-IFIs drugs as mentioned above, including the functional mechanism, activities in vitro and vivo, outcomes of clinical research, providing an overview of diverse anti-IFIs in the past decades and an outlook for the development of related drugs.
Melanin is implicated in the virulence of pathogenic fungi, providing defense against harsh environment stress and protective immunological response. However, the interaction of melanin with macrophage, a primary cell in inherent immunity, is poorly understood. To further elucidate pathogenic mechanism of fungi, this review describes the distribution and synthesis of melanin and the impact of melanin on macrophage.
It is very important to establish a suitable fungal infection animal model in the study of fungal diseases. As one of the insect animal models, the Galleria mellonella has many technical advantages over other animal models. It has been widely used in virulence, pathogenesis and immunological changes of Cryptococcus neoformans, Microsporidia, Trichophyton rubrum, Candida, dark fungi, Penicillium marneffei, Aspergillus flavus and Aspergillus fumigatus, etc. and the development of antibiotics and the treatment of systemic fungal infection as well as other various research fields. Because the results of infection model of wax borer are similar to those of mammals, the larvae of wax borer provide better initial screening and reduce the dependence on mammals in the experiment.
Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) is a newly developed microbial detection technology in recent years, which can quickly and accurately identify pathogenic fungi by analyzing ribosomal proteins. This paper reviews the application of MALDI-TOF MS in fungal identification, classification, antifungal susceptibility testing in vitro and direct identification of clinical microbial samples.
Trichoderma is ubiquitous in nature and most species are harmless to mankind. However, some of them can infect mankind and cause tricodermasis with a variety of clinical types that would be misdiagnosed. This systematical review are based on related literature in Medline and Chinese literature database, concerning pathogenic species and drug sensitivity of Trichoderma, and regional distribution, risk factors, clinical manifestation, diagnosis and treatment of trichodermasis.
It is conventional to identify filamentous fungi using morphological methods and genetic identification method. However, the former methods are usually influenced by the knowledge and skills of the inspectors, while the latter is cumbersome and expensive, and both of them are not suitable for routine clinical development. Therefore, it is imperative to find a rapid identification method. In this study, 254 clinical isolates of filamentous fungi were identified by MALDI-TOF MS (matrix-assisted laser desorption/ionization time-of-flight mass spectrometry) IVD (3.0 version) and the accuracy of the results was verified by ITS (internal transcribed spacer). The results showed that MALDI-TOF MS can identify most filamentous fungi quickly and accurately. The accuracy for identification of Trichophyton (100%), Trichosporon (100%), Mucor (100%) and Aspergillus (96.5%) was remarkably high, that of Microsporum canis (75%), Fusarium (50%), Curvularia lunata (46.2%) unsatisfactory. The overall accuracy rate for identification of filamentous fungi was 86.36%, and the coincidence rate with the results of ITS sequencing analysis was 83.97%.
Vulvovaginal candidiasis (VVC) is a common disease in women. In this study, 289 isolates of Candida spp. were obtained from VVC patients in Suzhou from January to December 2018. Identification and the test of in vitro susceptibility to nine antifungal drugs including echinocandins and neotriazoles of the pathogens were couducted. The D1/D2 gene of ribosomal RNA was used to identify Candida species. The in vitro sensitivity was tested by using M27-A3 protocol. Among 289 isolates, there were 259 isolates of Candida albicans, 14 isolates of Candida glabrata, 10 isolates of Candida krusei, 4 isolates of Candida tropicalis, and 2 isolates of Candida parapsilosis. Candida albicans showed high sensitivity to echinocanins in vitro, and its sensitivity to micafungin was higher than that to the other two echinocandins tested. It is sensitive to amphotericin B, 5-fluorocytosine and fluconazole, but less sensitive to itraconazole and voriconazole; it is also sensitive to posaconazole. Candida glabrata and Candida krusei have poor sensitivity to caspofungin, but have high sensitivity to micafungin and anidulafungin. The sensitivity of Candida glabrata to amphotericin B, 5-fluorocytosine and posaconazole is high, but poor to itraconazole. The MIC50/90 of Candida glabrata isolate to voriconazole is 0.5/1μg/mL in vitro. Candida krusei reveals 50% resistance to itraconazole and voriconazole; 4 isolates of Candida tropicalis display 50% resistance to itraconazole and 100% resistance to caspofungin, fluconazole, and voriconazole, and are sensitive to other 5 antifungal drugs. Candida parapsilosis was sensitive to 9 antifungal drugs. Candida albicans is predominant pathogen causing VVC in Suzhou, while Candida glabrata and Candida krusei. Secondary, showing lower sensitivity to itraconazole, voriconazole and caspofungin. The results indicate that periodical routine secretion examination culture and identification of pathogens are of benefit to local clinicians in Suzhou to develop a proper VVC treatment plan. Although echinomycin, amphotericin B, 5-fluorocytosine, and neotriazole have not been applied to the clinical treatment of VVC, these drugs are generally more sensitive to VVC pathogens and are expected to become a new choice for VVC patients.
Rhino-orbital-cerebral mycosis and lethal midline granuloma (LMG) share the same clinical manifestations of destructive ulcers occurring in the midline face. Sometimes, LMG can be combined with fungal infections, which are often considered secondary. In our previous case studies, Mucor irregularis PUTH 10050641 and Rhizopus oryzae PUTH 20111112 were isolated from the LMG tissue, and the patients were cured by antifungal therapy. We therefore speculated on that M. irregularis and R. oryzae may be involved in inducing atypical hyperplasia and expression of CD-56 and Ki-67 antigens. In order to verify our inference, mouse skin infection model was made using immunosuppressed ICR mice hypodermically injected with cyclophosphamide and M. irregularis PUTH 10050641 and R. oryzae PUTH 20111112 for observation of pathological changers. Skin specimens obtained were then cultured and histological analysis was made in 1, 2, 3, 4 and 5 weeks after inoculation. Inflammation expression models in different groups were analyzed. The result was that M. irregularis and R. oryzae successfully infected immunocompetent and immunosuppressed ICR mice. The thin-walled hyphae of the mucoralean fungi might be atypical that could not been recognized but could be cultured in media. Pleomorphic cell infiltration could be seen in the infected site, in which atypical cells could be seen. Angioinvasive phenomenon could be seen in the mouse models. A large number of mixed inflammatory cells could be seen pathologically and the proliferating cells gathered around fungal structure. The IOD of Ki-67 and CD-56 was significantly higher in the experimental groups than that in the control ones. Our preliminary studies have shown that M. irregularis and R. oryzae are involved in inducing atypical hyperplasia and NK cell aggregation.
Dermatophytes are important pathogens of superficial fungal infections, including five common pathogens: Trichophyton rubrum, Trichophyton interdigitale, Epidermophyton floccosum, Microsporum canis and Microsporum incurvatum. Real-time PCR-based high-resolution melting (HRM) assay was used to differentiate the five common dermatophytes, which was identified by DNA sequencing, and chitin synthase 1 was selected as the target gene to design amplification primers. Experimental results showed that five common dermatophytes could be effectively amplified and distinguished by different melting curves and melting temperature values. Negative controls and human DNA could not be amplified with 100% specificity. The analytical result of clinical strains was consistent with that of DNA sequencing. This study provides a rapid and accurate method for identification of five common dermatophytes, and valuable references for clinical applications and molecular epidemiological research.
Twelve isolates of Microsporum gypseum complex (Nannizzia species) from the children with tinea capitis or tinea faciei in our department from 2007 to 2016 were identified to species level by ITS/CHS1 sequence-based phylogenetic analysis. Five isolates were identified as Nannizzia gypsea (Microsporum gypseum), and other seven as Nannizzia incurvata (Microsporum incurvatum). The occurrence of multi-locus DNA polymorphism was confirmed in these two species by using sequence-related amplification polymorphism (SRAP) marking technique. The present study suggested the existence of Nannizzia incurvata in Hubei Province, and thus provided some experimental data and methodology for the molecular investigation of Nannizzia species in China.
Cryptococcus neoformans is an important clinical pathogenic fungus with capsule. In the previous work, our research group found that phenotypic differences between strains from different sources might be regulated by CNAG_01032 gene. In this study, CNAG_01032 knockout mutants were constructed in the clinically derived strains of Cryptococcus neoformans IFM56800 (C1) and IFM56769 (C2). The classical virulence factors of mutants and wild-type strains were detected. The utilization of 19 sugars by mutant and wild-type strains was tested using API 20C AUX test system, and in vivo pathogenicity testing was conducted through infecting BALB/c female mice via tail vein injection. The results showed that the CNAG-01032 gene knockout mutants under the backgrounds of clinical strains C1 and C2 were successfully constructed. There was no significant difference in growth at 37°C or melanin production between the mutants and the wild-type strains. However, the capsule thickness in ΔC1 and ΔC2 mutants decreased by 16.4% and 18.2%, respectively as compared with C1 and C2 strains. Both ΔC1 and ΔC2 mutants could not decompose and utilize cellobiose; there was no significant difference in virulence between the mutants and the wild type strains. Our data disclose that CNAG_01032 gene may be involved in the capsule synthesis and cellobiose metabolism in the Cryptococcus neoformans IFM56800 and IFM56769 strains of clinical origin.
Biological characteristics of PalI and PalI-like proteins of Sporothrix schenckii acquired from GenBank were analyzed by online bioinformatics analysis software. The biological properties of these two proteins, including physical and chemical properties, functional domains, secondary structure, epitopes, etc. were predicted. The theoretical molecular weights of these two proteins were 24.6kDa and 75.6kDa and their isoelectric points were about pH 9. They had the same functional domain and belonged to the same protein family with many PKC phosphorylation sites. Amino terminal regions of these two proteins were highly similar, bearing a strong resemblance to orthologous proteins of other fungi. Transmembrane regions and epitopes were found in both proteins. 3D structures of amino terminal regions of these two proteins were highly similar. These findings provide support for future experimental study.
The fungus Fonsecaea monophora invades the skin and subcutaneous tissue, and causes chromoblastomycosis in humanity, inducing skin morphological changes or ulceration. In severe cases, it can be crippled or even cancerous, seriously affecting the quality of patients’ life. In recent years, the use of invertebrates to replace mammals to construct infection models has gradually emerged, and its application range is increasingly expanding. In this study, we successfully established an animal model of F. monophora infection in vivo using larvae of Galleria mellonella, and plotted the survival curves of infected larvae, and observed changes in the surface and body cavity of larvae during infection. The immune defense response of the wax larvae against F. monophora was further investigated. This study indicates that the changes in hemocytes induced by pathogen infection have specific antifungal properties and can inhibit the growth of Candida albicans.
A standardized broth microdilution method was used to test the antifungal activity of the sterilizing agent chlorhexidine (CHX) alone or in combination with the antifungal agent bifonazole (BFZ) against 17 clinical isolates of Candida spp. A disk diffusion test was also used to evaluate the antifungal effect of these two drugs against Candida spp. by measuring the inhibition zone diameters. We found that the minimal inhibitory concentrations (MICs) for CHX alone against Candida spp. was over 16μg/mL. The combination of CHX with BFZ showed synergistic activity in vitro against all Candida isolates.
Candida albicans is the leading fungal human pathogen causing life-threatening infection in immunocompromised individuals. Fluconazole is the most prevalent antifungal drug in clinical use, but its therapeutic efficacy is compromised by the emergence of drug resistant strains. Looking for new antifungal targets or chemical compounds capable of enhancing the antifungal abilities so as to replace existing antifungal drugs is urgently needful. We found TOR signal passway inhibitor ridaforolimus had ability to resist common Candida species. In this study, in vitro effect of ridaforolimus alone and in combination with fluconazole against Candida spp. was tested through disk diffusion and standardized broth microdilution methods. The results showed that ridaforolimus alone had great anti-Candida ability. It can also enhance fluconazole and change fluconazole’s function of fungistasis into fungicidal function, thereby reversing resistance of C. albicans to fluconazole. Our data indicate that ridaforolimus has great potential for further use to treat invasive candidiasis.
Periodic subculture and cryopreservation are the most usually used methods for fungal storage. To compare the keeping effectiveness of periodic subculture and cryopreservation in preserving pathogenic fungi, 689 strains of five-year preservation using these two methods were detected. Periodic subculture was that cultures on potato dextrose agar were stored in refrigerator at 4°C and subculture was made every 6 months. As for cryopreservation, fungal cultures on potato dextrose agar were stored in freezer at -80°C in tubes containing 1mL sterile 10% glycerol. After 5-year period preservation, the strains were removed and subcultured on potato dextrose agar to detect the survivability. Comparison between the methods of periodic subculture and cryopreservation indicated that the survival rates of Candida spp., Cryptococcus neoformans, Trichophyton spp., Aspergillus spp. and Sporothirix spp. showed no statistical difference. For Microsporum spp. and Talaromyces marneffei, the survival rate of the cultures cryopreserved was higher than that of the cultures periodically subcultured. For Fonsecaea spp., the survival rate of the cultures cryopreserved was lower than that of the cultures periodically subcultured. Therefore, cryopreservation is a better storage method for most fungi isolated in clinic using 10% glycerol as cryoprotectant as compared with periodic subculture. However, cryopreservation is not suitable for Fonsecaea spp.
Kerion is characterized by human dermal severe inflammation caused by zoophilic or geophilic fungi, and mostly seen among children usually without typical manifestation, and therefore it is easily spread. It would cause elevated plaque or pustule rapidly due to terrible inflammation, and could be misdiagnosed as solitary bacterial infection, detaining proper therapeutic progress. Up to now, there is no any certain consensus of treatment regimen. We here present a case of children refractory kerion completely cured by combined treatment of voriconazole and photodynamic therapy after poor therapeutic efficacy of terbinafine and itraconazole incorporated regimen.
