Loss of mammalian glutaminase orthologs impairs sperm function in Caenorhabditis elegans.

The decline in sperm function is a major cause of human male infertility. Glutaminase, a mitochondrial enzyme that catalyzes the hydrolysis of glutamine to generate glutamate, takes part in many diverse biological processes such as neurotransmission, metabolism, and cellular senescence. Here we report the role of glutaminase in regulating sperm function. By generating a triple mutant that harbors a loss-of-function allele for each of all three mammalian glutaminase orthologs, we found that glutaminase gene activity is required for optimal Caenorhabditis elegans sperm function. Tissue-specific gene manipulations showed that germline glutaminase activity plays an important role. Moreover, transcriptional profiling and antioxidant treatment suggested that glutaminase promotes sperm function by maintaining cellular redox homeostasis. As maintaining a low level of ROS is crucial to human sperm function, it is very likely that glutaminase plays a similar role in humans and therefore can be a potential target for treating human male infertility.

Application Value of Nutrition Support Team in Chemotherapy Period of Colon Cancer Based on Internet Multidisciplinary Treatment Mode.

Objective: To explore the application value of the nutrition support team in chemotherapy period of colon cancer based on the internet multidisciplinary treatment mode. Methods: For the method of retrospective study, 90 patients with colon cancer admitted to our hospital from August 2018 to August 2020 were selected as the study subjects. They were equally divided into the experimental group (n = 45) and the control group (n = 45) according to the order of initials and the method of parity group. The control group was given conventional nutrition support, and the experimental group was given the nutrition support under the internet multidisciplinary treatment mode. The serum tumor marker levels (CEA and CA19-9), immune function indexes, nutrition indicators, and the incidence of adverse reactions were compared between the two groups before and after intervention. Results: The serum tumor marker levels in the experimental group after intervention were significantly lower than those in the control group (P < 0.001). The immune function indexes in the experimental group after intervention were significantly better than those in the control group (P < 0.001). The nutrition indicators in the experimental group after intervention were significantly better than those in the control group (P < 0.001). The incidence of gastrointestinal adverse reactions above grade 2 in the experimental group was significantly lower than that in the control group (P < 0.05). There were 20 patients with myelosuppression, 2 patients with neurotoxicity, and 1 patient with hand and foot syndrome in the experimental group, while 22 patients with myelosuppression, 4 patients with neurotoxicity, and 2 patients with hand and foot syndrome in the control group, with no significant difference in the incidence of adverse reactions between the two groups (P > 0.05). Conclusion: The nutrition support team under the internet multidisciplinary treatment mode can improve the immune function of chemotherapy patients with colon cancer and enhance their nutritional level, thereby reducing the incidence of adverse reactions and improving the chemotherapy effects.

A Genome-Wide RNAi Screen for Enhancers of a Germline Tumor Phenotype Caused by Elevated GLP-1/Notch Signaling in Caenorhabditis elegans.

Stem cells are tightly controlled in vivo Both the balance between self-renewal and differentiation and the rate of proliferation are often regulated by multiple factors. The Caenorhabditis elegans hermaphrodite germ line provides a simple and accessible system for studying stem cells in vivo In this system, GLP-1/Notch activity prevents the differentiation of distal germ cells in response to ligand production from the nearby distal tip cell, thereby supporting a stem cell pool. However, a delay in germline development relative to somatic gonad development can cause a pool of undifferentiated germ cells to persist in response to alternate Notch ligands expressed in the proximal somatic gonad. This pool of undifferentiated germ cells forms a proximal tumor that, in adulthood, blocks the oviduct. This type of "latent niche"-driven proximal tumor is highly penetrant in worms bearing the temperature-sensitive weak gain-of-function mutation glp-1(ar202) at the restrictive temperature. At the permissive temperature, few worms develop tumors. Nevertheless, several interventions elevate the penetrance of proximal tumor formation at the permissive temperature, including reduced insulin signaling or the ablation of distal-most sheath cells. To systematically identify genetic perturbations that enhance proximal tumor formation, we sought genes that, upon RNAi depletion, elevate the percentage of worms bearing proximal germline tumors in glp-1(ar202) at the permissive temperature. We identified 43 genes representing a variety of functional classes, the most enriched of which is "translation". Some of these genes also influence the distal germ line, and some are conserved genes for which genetic interactions with Notch were not previously known in this system.

Sp9 Regulates Medial Ganglionic Eminence-Derived Cortical Interneuron Development.

Immature neurons generated by the subpallial MGE tangentially migrate to the cortex where they become parvalbumin-expressing (PV+) and somatostatin (SST+) interneurons. Here, we show that the Sp9 transcription factor controls the development of MGE-derived cortical interneurons. SP9 is expressed in the MGE subventricular zone and in MGE-derived migrating interneurons. Sp9 null and conditional mutant mice have approximately 50% reduction of MGE-derived cortical interneurons, an ectopic aggregation of MGE-derived neurons in the embryonic ventral telencephalon, and an increased ratio of SST+/PV+ cortical interneurons. RNA-Seq and SP9 ChIP-Seq reveal that SP9 regulates MGE-derived cortical interneuron development through controlling the expression of key transcription factors Arx, Lhx6, Lhx8, Nkx2-1, and Zeb2 involved in interneuron development, as well as genes implicated in regulating interneuron migration Ackr3, Epha3, and St18. Thus, Sp9 has a central transcriptional role in MGE-derived cortical interneuron development.

SP8 and SP9 coordinately promote D2-type medium spiny neuron production by activating Six3 expression.

Dopamine receptor DRD1-expressing medium spiny neurons (D1 MSNs) and dopamine receptor DRD2-expressing medium spiny neurons (D2 MSNs) are the principal projection neurons in the striatum, which is divided into dorsal striatum (caudate nucleus and putamen) and ventral striatum (nucleus accumbens and olfactory tubercle). Progenitors of these neurons arise in the lateral ganglionic eminence (LGE). Using conditional deletion, we show that mice lacking the transcription factor genes Sp8 and Sp9 lose virtually all D2 MSNs as a result of reduced neurogenesis in the LGE, whereas D1 MSNs are largely unaffected. SP8 and SP9 together drive expression of the transcription factor Six3 in a spatially restricted domain of the LGE subventricular zone. Conditional deletion of Six3 also prevents the formation of most D2 MSNs, phenocopying the Sp8/9 mutants. Finally, ChIP-Seq reveals that SP9 directly binds to the promoter and a putative enhancer of Six3 Thus, this study defines components of a transcription pathway in a regionally restricted LGE progenitor domain that selectively drives the generation of D2 MSNs.

Transcription Factors Sp8 and Sp9 Coordinately Regulate Olfactory Bulb Interneuron Development.

Neural stem cells in the postnatal telencephalic ventricular-subventricular zone (V-SVZ) generate new interneurons, which migrate tangentially through the rostral migratory stream (RMS) into the olfactory bulb (OB). The Sp8 and Sp9 transcription factors are expressed in neuroblasts, as well as in the immature and mature interneurons in the V-SVZ-RMS-OB system. Here we show that Sp8 and Sp9 coordinately regulate OB interneuron development: although Sp9 null mutants show no major OB interneuron defect, conditional deletion of both Sp8 and Sp9 resulted in a much more severe reduction of OB interneuron number than that observed in the Sp8 conditional mutant mice, due to defects in neuronal differentiation, tangential and radial migration, and increased cell death in the V-SVZ-RMS-OB system. RNA-Seq and RNA in situ hybridization reveal that, in Sp8/Sp9 double mutant mice, but not in Sp8 or Sp9 single mutant mice, newly born neuroblasts in the V-SVZ-RMS-OB system fail to express Prokr2 and Tshz1 expression, genes with known roles in promoting OB interneuron differentiation and migration, and that are involved in human Kallmann syndrome.

The Zinc Finger Transcription Factor Sp9 Is Required for the Development of Striatopallidal Projection Neurons.

Striatal medium-sized spiny neurons (MSNs), composed of striatonigral and striatopallidal neurons, are derived from the lateral ganglionic eminence (LGE). We find that the transcription factor Sp9 is expressed in LGE progenitors that generate nearly all striatal MSNs and that Sp9 expression is maintained in postmitotic striatopallidal MSNs. Sp9-null mice lose most striatopallidal MSNs because of decreased proliferation of striatopallidal MSN progenitors and increased Bax-dependent apoptosis, whereas the development of striatonigral neurons is largely unaffected. ChIP qPCR provides evidence that Ascl1 directly binds the Sp9 promoter. RNA-seq and in situ hybridization reveal that Sp9 promotes expression of Adora2a, P2ry1, Gpr6, and Grik3 in the LGE and striatum. Thus, Sp9 is crucial for the generation, differentiation, and survival of striatopallidal MSNs.

Transcription factors COUP-TFI and COUP-TFII are required for the production of granule cells in the mouse olfactory bulb.

Neural stem cells (NSCs) persist in the adult mammalian subventricular zone (SVZ) of the lateral ventricle. Primary NSCs generate rapidly dividing intermediate progenitor cells, which in turn generate neuroblasts that migrate along the rostral migratory stream (RMS) to the olfactory bulb (OB). Here, we have examined the role of the COUP-TFI and COUP-TFII orphan nuclear receptor transcription factors in mouse OB interneuron development. We observed that COUP-TFI is expressed in a gradient of low rostral to high caudal within the postnatal SVZ neural stem/progenitor cells. COUP-TFI is also expressed in a large number of migrating neuroblasts in the SVZ and RMS, and in mature interneurons in the OB. By contrast, very few COUP-TFII-expressing (+) cells exist in the SVZ-RMS-OB pathway. Conditional inactivation of COUP-TFI resulted in downregulation of tyrosine hydroxylase expression in the OB periglomerular cells and upregulation of COUP-TFII expression in the SVZ, RMS and OB deep granule cell layer. In COUP-TFI/COUP-TFII double conditional mutant SVZ, cell proliferation was increased through the upregulation of the proneural gene Ascl1. Furthermore, COUP-TFI/II-deficient neuroblasts had impaired migration, resulting in ectopic accumulation of calretinin (CR)+ and NeuN+ cells, and an increase in apoptotic cell death in the SVZ. Finally, we found that most Pax6+ and a subset of CR+ granular cells were lost in the OB. Taken together, these results suggest that COUP-TFI/II coordinately regulate the proliferation, migration and survival of a subpopulation of Pax6+ and CR+ granule cells in the OB.