2022 Vol. 43, No. 2

Full issue 
2022, 43(2): 1-1.
Chimeric antigen receptor T cells (CAR-T cells) are engineered recombinant T cells, which were initially used to treat hematopoietic malignancies and are now widely used in the treatment of various diseases. Considering their intrinsic targeting efficiency, CAR-T cells show considerable potential in the treatment of autoimmune diseases. Furthermore, regulatory T cells (Treg), a subset of CD4 T cells exhibiting immunosuppressive functions, have attracted increasing attention regarding CAR-Treg cell production. In this review, we report on recent developments in preclinical and clinical studies on CAR-T cells in autoimmune diseases and provide an outlook on opportunities and challenges of CAR-T application in such diseases.
Up to 20% of women experience stress-related disorders during the postpartum period; however, little is known about the specific neural circuitry by which maternal stress exerts its negative impacts on mental health and maternal caregiving behavior. Theoretically, such a circuitry should serve as an interface between the stress response system and maternal neural network, transmitting stress signals to the neural circuitry that mediates maternal behavior. In this paper, I propose that the lateral habenula (LHb) serves this interface function. Evidence shows that the LHb plays a key role in encoding stress-induced effects and in the pathophysiology of major depression and stress-related anxiety, and thus may play a role in maternal behavior as part of the maternal brain network. I hypothesize that maternal stress acts upon the LHb and two of its major downstream targets, i.e., ventral tegmental area (VTA) and dorsal raphe nucleus (DRN), compromising the maternal care and contributing to postpartum mental disorders. This hypothesis makes three predictions: (1) maternal stress enhances LHb neuronal activity; (2) activation of DRN- and VTA-projecting neurons in the LHb mimics the detrimental effects of maternal stress on maternal behavior; and (3) suppression of DRN- and VTA-projecting neurons in the LHb attenuates the detrimental effects of maternal stress on maternal care in stressed mothers. Confirmation of this hypothesis is expected to enhance our understanding of the neurocircuit mechanisms mediating stress effects on maternal behavior.
Letter to the editor
Environmental DNA (eDNA) integrated with metabarcoding is a promising and powerful tool for species composition and biodiversity assessment in aquatic ecosystems and is increasingly applied to evaluate fish diversity. To date, however, no standardized eDNA-based protocol has been established to monitor fish diversity. In this study, we investigated and compared two filtration methods and three DNA extraction methods using three filtration water volumes to determine a suitable approach for eDNA-based fish diversity monitoring in the Pearl River Estuary (PRE), a highly anthropogenically disturbed estuarine ecosystem. Compared to filtration-based precipitation, direct filtration was a more suitable method for eDNA metabarcoding in the PRE. The combined use of DNeasy Blood and Tissue Kit (BT) and traditional phenol/chloroform (PC) extraction produced higher DNA yields, amplicon sequence variants (ASVs), and Shannon diversity indices, and generated more homogeneous and consistent community composition among replicates. Compared to the other combined protocols, the PC and BT methods obtained better species detection, higher fish diversity, and greater consistency for the filtration water volumes of 1 000 and 2 000 mL, respectively. All eDNA metabarcoding protocols were more sensitive than bottom trawling in the PRE fish surveys and combining two techniques yielded greater taxonomic diversity. Furthermore, combining traditional methods with eDNA analysis enhanced accuracy. These results indicate that methodological decisions related to eDNA metabarcoding should be made with caution for fish community monitoring in estuarine ecosystems.
Red tilapia (Oreochromis spp.) is one of the most popular fish in China due to its bright red appearance, fast growth rate, and strong adaptability. Understanding the sex determination mechanisms is of vital importance for the selection of all-male lines to increase aquacultural production of red tilapia. In this research, the genetic architecture for sex from four mapping populations (n=1 090) of red tilapia was analyzed by quantitative trait loci (QTL)-seq, linkage-based QTL mapping, and linkage disequilibrium (LD)-based genome-wide association studies. Two genome-wide significant QTL intervals associated with sex were identified on ChrLG1 (22.4–23.9 Mb) and ChrLG23 (32.0–35.9 Mb), respectively. The QTL on ChrLG1 was detected in family 1 (FAM1), FAM2, and FAM4, and the other QTL on ChrLG23 was detected in FAM3 and FAM4. Four microsatellite markers located within the QTL were successfully developed for marker-assisted selection. Interestingly, three (lpp, sox14, and amh) of the 12 candidate genes located near or on the two QTL intervals were abundantly expressed in males, while the remaining genes were more highly expressed in females. Seven genes (scly, ube3a, lpp, gpr17, oca2, cog4, and atp10a) were significantly differentially expressed between the male and female groups. Furthermore, LD block analysis suggested that a cluster of genes on ChrLG23 may participate in regulating sex development in red tilapia. Our study provides important information on the genetic architecture of sex in red tilapia and should facilitate further exploration of sex determination mechanisms in this species.
Letter to the editor
Konosirus punctatus is an economically important marine fishery resource and is widely distributed from the Indian to Pacific oceans. It is a good non-model species for genetic studies on salinity and temperature adaptation. However, a high-quality reference genome has not yet been reported. Here, an 800.00 Mb high-quality chromosome-level genome with a contig N50 length of 2.14 Mb was assembled using Illumina, Pacific Biosciences, and Hi-C sequencing technology. The assembled sequences were anchored to 24 pseudochromosomes by the Hi-C data. In total, 24 298 protein-coding genes were predicted, 91.08% of which were successfully annotated with putative functions. Furthermore, 587 putative genes were identified as being under positive selection. This new high-quality K. punctatus reference genome provides a fundamental resource for a deeper understanding of temperature and salinity adaptation and species conservation.
The incidence of myopia has increased rapidly in recent decades, suggesting that environmental factors, such as light, may be an important cause. Correlated color temperature (CCT) is a commonly used index to quantify the spectral composition of light. Here, we used 32 juvenile monkeys (16 females and 16 males) and selected four kinds of light with typical but different CCTs to study the relationship between CCT and ocular axial elongation. After 365 days of observation, ocular axial elongation under low-CCT light was smaller than that under high-CCT light and this effect was robust and stable over the entire observation period. As excessive axial elongation is the main cause of juvenile myopia, these results provide a new approach for the prevention of juvenile myopia.
Many mammals risk damage from oxidative stress stemming from frequent dives (i.e., cycles of ischemia/reperfusion and hypoxia/reoxygenation), high altitude and subterranean environments, or powered flight. Purine metabolism is an essential response to oxidative stress, and an imbalance between purine salvage and de novo biosynthesis pathways can generate damaging reactive oxygen species (ROS). Here, we examined the evolution of 117 purine metabolism-related genes to explore the accompanying molecular mechanisms of enhanced purine metabolism in mammals under high oxidative stress. We found that positively selected genes, convergent changes, and nonparallel amino acid substitutions are possibly associated with adaptation to oxidative stress in mammals. In particular, the evolution of convergent genes with cAMP and cGMP regulation roles may protect mammals from oxidative damage. Additionally, 32 genes were identified as under positive selection in cetaceans, including key purine salvage enzymes (i.e., HPRT1), suggesting improved re-utilization of non-recyclable purines avoid hypoxanthine accumulation and reduce oxidative stress. Most intriguingly, we found that six unique substitutions in cetacean xanthine dehydrogenase (XDH), an enzyme that regulates the generation of the ROS precursor xanthine oxidase (XO) during ischemic/hypoxic conditions, show enhanced enzyme activity and thermal stability and diminished XO conversion activity. These functional adaptations are likely beneficial for cetaceans by reducing radical oxygen species production during diving. In summary, our findings offer insights into the molecular and functional evolution of purine metabolism genes in mammalian oxidative stress adaptations.
We aimed to characterize NDM-5-producing Enterobacteriaceae from aquatic products in Guangzhou, China. A total of 196 intestinal samples of grass carp collected in 2019 were screened for carbapenemase genes. Characterization of blaNDM-5 positive isolates and plasmids was determined by antimicrobial susceptibility testing, conjugation experiments, Illumina HiSeq, and Nanopore sequencing. One Citrobacter freundii and six Escherichia coli strains recovered from seven intestinal samples were verified as blaNDM-5 carriers (3.57%, 7/196). The blaNDM-5 genes were located on the IncX3 (n=5), IncHI2 (n=1), or IncHI2-IncF (n=1) plasmids. All blaNDM-5-bearing plasmids were transferred by conjugation at frequencies of ~10−4–10−6. Based on sequence analysis, the IncHI2 plasmid pHNBYF33-1 was similar to other blaNDM-5-carrying IncHI2 plasmids deposited in GenBank from Guangdong ducks. In all IncHI2 plasmids, blaNDM-5 was embedded in a novel transposon, Tn7051 (IS3000-ΔISAba125-IS5-ΔISAba125-blaNDM-5-bleMBL-trpF-tat-∆dct-IS26-∆umuD-∆ISKox3-IS3000), which was identical to the genetic structure surrounding blaNDM-5 found in some IncX3 plasmids. The IncHI2-IncF hybrid plasmid pHNTH9F11-1 was formed by homologous recombination of the blaNDM-5-carrying IncHI2 plasmid and a heavy-metal-resistant IncF plasmid through ∆Tn1721. To the best of our knowledge, this is the first report on the characterization of blaNDM-5-bearing plasmids in fish in China. The IncHI2 plasmid pHNBYF33-1 may be transmitted from ducks, considering the common duck-fish freshwater aquaculture system in Guangdong. Tn7051 is likely responsible for the transfer of blaNDM-5 from IncX3 to IncHI2 plasmids in Enterobacteriaceae, resulting in the expansion of transmission vectors of blaNDM-5.
Sibling cannibalism is relatively common in nature, but its evolution in birds and certain other vertebrates with extended parental care had been discarded. Here, however, we demonstrate its regular occurrence in two European populations of the Eurasian hoopoe (Upupa epops) and explore possible adaptive and non-adaptive explanations. Results showed that sibling cannibalism was more frequently detected in Spain (51.7%) than in Austria (5.9%). In these two populations, the hoopoes laid similar clutch sizes, resulting in similar fledging production, but hatching failures were more frequent in the northern population. Consequently, having more nestlings condemned to die in the southern population may explain the higher incidence of sibling cannibalism. In accordance with this interpretation, hatching span and failure, but not breeding date, explained the probability of sibling cannibalism in the Spanish hoopoes, while all three variables predicted brood reduction intensity. Furthermore, experimental food supply reduced the probability of sibling cannibalism, but not the intensity of brood reduction. Finally, females allocated fewer resources to the smallest nestlings when they were going to starve, but not necessarily when they were going to be used as food for their siblings. These results suggest that hoopoes produce extra eggs that, in the case of reduced hatching failure and food scarcity, produce nestlings that are used to feed older siblings. These findings provide the first evidence that sibling cannibalism occurs regularly in a bird species, thus expanding our evolutionary understanding of clutch size, hatching asynchrony, parent-offspring conflict, infanticide, and sibling cannibalism in the animal kingdom.
Environmental temperature serves as a major driver of adaptive changes in wild organisms. To discover the mechanisms underpinning cold tolerance in domestic animals, we sequenced the genomes of 28 cattle from warm and cold areas across China. By characterizing the population structure and demographic history, we identified two genetic clusters, i.e., northern and southern groups, as well as a common historic population peak at 30 kilo years ago. Genomic scan of cold-tolerant breeds determined potential candidate genes in the thermogenesis-related pathways that were under selection. Specifically, functional analysis identified a substitution of PRDM16 (p.P779L) in northern cattle, which maintains brown adipocyte formation by boosting thermogenesis-related gene expression, indicating a vital role of this gene in cold tolerance. These findings provide a basis for genetic variation in domestic cattle shaped by environmental temperature and highlight the role of reverse mutation in livestock species.
Organisms produce high levels of reactive oxygen species (ROS) to kill pathogens or act as signaling molecules to induce immune responses; however, excessive ROS can result in cell death. To maintain ROS balance and cell survival, mitophagy selectively eliminates damaged mitochondria via mitophagy receptors in vertebrates. In marine invertebrates, however, mitophagy and its functions remain largely unknown. In the current study, Vibrio splendidus infection damaged mitochondrial morphology in coelomocytes and reduced mitochondrial membrane potential (ΔΨm) and mitophagosome formation. The colocalization of mitochondria and lysosomes further confirmed that lipopolysaccharide (LPS) treatment increased mitophagy flux. To explore the regulatory mechanism of mitophagy, we cloned Bcl2/adenovirus E1B 19 kDa protein-interacting protein 3 (BNIP3), a common mitophagy receptor, from sea cucumber Apostichopus japonicus (AjBNIP3) and confirmed that AjBNIP3 was significantly induced and accumulated in mitochondria after V. splendidus infection and LPS exposure. At the mitochondrial membrane, AjBNIP3 interacts with microtubule-associated protein 1 light chain 3 (LC3) on phagophore membranes to mediate mitophagy. After AjBNIP3 interference, mitophagy flux decreased significantly. Furthermore, AjBNIP3-mediated mitophagy was activated by ROS following the addition of exogenous hydrogen peroxide (H2O2), ROS scavengers, and ROS inhibitors. Finally, inhibition of BNIP3-mediated mitophagy by AjBNIP3 small interfering RNA (siRNA) or high concentrations of lactate increased apoptosis and decreased coelomocyte survival. These findings highlight the essential role of AjBNIP3 in damaged mitochondrial degradation during mitophagy. This mitophagy activity is required for coelomocyte survival in A. japonicus against V. splendidus infection.