LRP5 promotes cancer stem cell traits and chemoresistance in colorectal cancer

The overactivation of canonical Wnt/β‐catenin pathway and the maintenance of cancer stem cells (CSCs) are essential for the onset and malignant progression of most human cancers. However, their regulatory mechanism in colorectal cancer (CRC) has not yet been well demonstrated. Low‐density lipoprotein receptor‐related protein 5 (LRP5) has been identified as an indispensable co‐receptor with frizzled family members for the canonical Wnt/β‐catenin signal transduction. Herein, we show that activation of LRP5 gene promotes CSCs‐like phenotypes, including tumorigenicity and drug resistance in CRC cells, through activating the canonical Wnt/β‐catenin and IL‐6/STAT3 signalling pathways. Clinically, the expression of LRP5 is upregulated in human CRC tissues and closely associated with clinical stages of patients with CRC. Further analysis showed silencing of endogenous LRP5 gene is sufficient to suppress the CSCs‐like phenotypes of CRC through inhibiting these two pathways. In conclusion, our findings not only reveal a regulatory cross‐talk between canonical Wnt/β‐catenin signalling pathway, IL‐6/STAT3 signalling pathway and CD133‐related stemness that promote the malignant behaviour of CRC, but also provide a valuable target for the diagnosis and treatment of CRC.     

Fungal‐induced glycolysis in macrophages promotes colon cancer by enhancing innate lymphoid cell secretion of IL‐22

Incorporation of microbiome data has recently become important for prevention, diagnosis, and treatment of colorectal cancer, and several species of bacteria were shown to be associated with carcinogenesis. However, the role of commensal fungi in colon cancer remains poorly understood. Here, we report that mice lacking the c‐type lectin Dectin‐3 (Dectin‐3 ^−/−) show increased tumorigenesis and Candida albicans burden upon chemical induction. Elevated C. albicans load triggered glycolysis in macrophages and interleukin‐7 (IL‐7) secretion. IL‐7 induced IL‐22 production in RORγt⁺ (group 3) innate lymphoid cells (ILC3s) via aryl hydrocarbon receptor and STAT3. Consistently, IL‐22 frequency in tumor tissues of colon cancer patients positively correlated with fungal burden, indicating the relevance of this regulatory axis in human disease. These results establish a C. albicans‐driven crosstalk between macrophages and innate lymphoid cells in the intestine and expand our understanding on how commensal mycobiota regulate host immunity and promote tumorigenesis.     

Microglial PD‐1 stimulation by astrocytic PD‐L1 suppresses neuroinflammation and Alzheimer’s disease pathology

Chronic neuroinflammation is a pathogenic component of Alzheimer’s disease (AD) that may limit the ability of the brain to clear amyloid deposits and cellular debris. Tight control of the immune system is therefore key to sustain the ability of the brain to repair itself during homeostasis and disease. The immune‐cell checkpoint receptor/ligand pair PD‐1/PD‐L1, known for their inhibitory immune function, is expressed also in the brain. Here, we report upregulated expression of PD‐L1 and PD‐1 in astrocytes and microglia, respectively, surrounding amyloid plaques in AD patients and in the APP/PS1 AD mouse model. We observed juxtamembrane shedding of PD‐L1 from astrocytes, which may mediate ectodomain signaling to PD‐1‐expressing microglia. Deletion of microglial PD‐1 evoked an inflammatory response and compromised amyloid‐β peptide (Aβ) uptake. APP/PS1 mice deficient for PD‐1 exhibited increased deposition of Aβ, reduced microglial Aβ uptake, and decreased expression of the Aβ receptor CD36 on microglia. Therefore, ineffective immune regulation by the PD‐1/PD‐L1 axis contributes to Aβ plaque deposition during chronic neuroinflammation in AD.     

Structural mechanism for modulation of functional amyloid and biofilm formation by Staphylococcal Bap protein switch

The Staphylococcal Bap proteins sense environmental signals (such as pH, [Ca²⁺]) to build amyloid scaffold biofilm matrices via unknown mechanisms. We here report the crystal structure of the aggregation‐prone region of Staphylococcus aureus Bap which adopts a dumbbell‐shaped fold. The middle module (MM) connecting the N‐terminal and C‐terminal lobes consists of a tandem of novel double‐Ca²⁺‐binding motifs involved in cooperative interaction networks, which undergoes Ca²⁺‐dependent order–disorder conformational switches. The N‐terminal lobe is sufficient to mediate amyloid aggregation through liquid–liquid phase separation and maturation, and subsequent biofilm formation under acidic conditions. Such processes are promoted by disordered MM at low [Ca²⁺] but inhibited by ordered MM stabilized by Ca²⁺ binding, with inhibition efficiency depending on structural integrity of the interaction networks. These studies illustrate a novel protein switch in pathogenic bacteria and provide insights into the mechanistic understanding of Bap proteins in modulation of functional amyloid and biofilm formation, which could be implemented in the anti‐biofilm drug design.     

“Protein aggregates” contain RNA and DNA,entrapped by misfolded proteins but largely rescued by slowing translational elongation

All neurodegenerative diseases feature aggregates, which usually contain disease‐specific diagnostic proteins; non‐protein constituents, however, have rarely been explored. Aggregates from SY5Y‐APP_Sw neuroblastoma, a cell model of familial Alzheimer''s disease, were crosslinked and sequences of linked peptides identified. We constructed a normalized “contactome” comprising 11 subnetworks, centered on 24 high‐connectivity hubs. Remarkably, all 24 are nucleic acid‐binding proteins. This led us to isolate and sequence RNA and DNA from Alzheimer''s and control aggregates. RNA fragments were mapped to the human genome by RNA‐seq and DNA by ChIP‐seq. Nearly all aggregate RNA sequences mapped to specific genes, whereas DNA fragments were predominantly intergenic. These nucleic acid mappings are all significantly nonrandom, making an artifactual origin extremely unlikely. RNA (mostly cytoplasmic) exceeded DNA (chiefly nuclear) by twofold to fivefold. RNA fragments recovered from AD tissue were ~1.5‐to 2.5‐fold more abundant than those recovered from control tissue, similar to the increase in protein. Aggregate abundances of specific RNA sequences were strikingly differential between cultured SY5Y‐APP_Sw glioblastoma cells expressing APOE3 vs. APOE4, consistent with APOE4 competition for E‐box/CLEAR motifs. We identified many G‐quadruplex and viral sequences within RNA and DNA of aggregates, suggesting that sequestration of viral genomes may have driven the evolution of disordered nucleic acid‐binding proteins. After RNA‐interference knockdown of the translational‐procession factor EEF2 to suppress translation in SY5Y‐APP_Sw cells, the RNA content of aggregates declined by >90%, while reducing protein content by only 30% and altering DNA content by ≤10%. This implies that cotranslational misfolding of nascent proteins may ensnare polysomes into aggregates, accounting for most of their RNA content.     

The cellular modifier MOAG‐4/SERF drives amyloid formation through charge complementation

While aggregation‐prone proteins are known to accelerate aging and cause age‐related diseases, the cellular mechanisms that drive their cytotoxicity remain unresolved. The orthologous proteins MOAG‐4, SERF1A, and SERF2 have recently been identified as cellular modifiers of such proteotoxicity. Using a peptide array screening approach on human amyloidogenic proteins, we found that SERF2 interacted with protein segments enriched in negatively charged and hydrophobic, aromatic amino acids. The absence of such segments, or the neutralization of the positive charge in SERF2, prevented these interactions and abolished the amyloid‐promoting activity of SERF2. In protein aggregation models in the nematode worm Caenorhabditis elegans, protein aggregation and toxicity were suppressed by mutating the endogenous locus of MOAG‐4 to neutralize charge. Our data indicate that MOAG‐4 and SERF2 drive protein aggregation and toxicity by interactions with negatively charged segments in aggregation‐prone proteins. Such charge interactions might accelerate primary nucleation of amyloid by initiating structural changes and by decreasing colloidal stability. Our study points at charge interactions between cellular modifiers and amyloidogenic proteins as potential targets for interventions to reduce age‐related protein toxicity.     

Molecular basis of cross‐species ACE2 interactions with SARS‐CoV‐2‐like viruses of pangolin origin

Correction to: The EMBO Journal (2021) 40: e107786. DOI 10.15252/embj.2021107786 | Published online 8 June 2021The authors would like to add three references to the paper: Starr et al and Zahradník et al also reported that the Q498H or Q498R mutation has enhanced binding affinity to ACE2; and Liu et al reported on the binding of bat coronavirus to ACE2.Starr et al and Zahradník et al have now been cited in the Discussion section, and the following sentence has been corrected from:“According to our data, the SARS‐CoV‐2 RBD with Q498H increases the binding strength to hACE2 by 5‐fold, suggesting the Q498H mutant is more ready to interact with human receptor than the wildtype and highlighting the necessity for more strict control of virus and virus‐infected animals”.to“Here, according to our data and two recently published papers, the SARS‐CoV‐2 RBD with Q498H or Q498R increases the binding strength to hACE2 (Starr et al, 2020; Zahradník et al, 2021), suggesting the mutant with Q498H or Q498R is more ready to interact with human receptor than the wild type and highlighting the necessity for more strict control of virus and virus‐infected animals”.The Liu et al citation has been added to the following sentence:“In another paper published by our group recently, RaTG13 RBD was found to bind to hACE2 with much lower binding affinity than SARS‐CoV‐2 though RaTG13 displays the highest whole‐genome sequence identity (96.2%) with the SARS‐CoV‐2 (Liu et al, 2021)”.Additionally, the authors have added the GISAID accession IDs to the sequence names of the SARS‐CoV‐2 in two human samples (Discussion section). To make identification unambiguous, the sequence names have been updated from “SA‐lsf‐27 and SA‐lsf‐37” to “GISAID accession ID: EPI_ISL_672581 and EPI_ISL_672589”.Lastly, the authors declare in the Materials and Methods section that all experiments employed SARS‐CoV‐2 pseudovirus in cultured cells. These experiments were performed in a BSL‐2‐level laboratory and approved by Science and Technology Conditions Platform Office, Institute of Microbiology, Chinese Academy of Sciences.These changes are herewith incorporated into the paper.     

Loss of enteric neuronal Ndrg4 promotes colorectal cancer via increased release of Nid1 and Fbln2

The N‐Myc Downstream‐Regulated Gene 4 (NDRG4), a prominent biomarker for colorectal cancer (CRC), is specifically expressed by enteric neurons. Considering that nerves are important members of the tumor microenvironment, we here establish different Ndrg4 knockout (Ndrg4 ^−/−) CRC models and an indirect co‐culture of primary enteric nervous system (ENS) cells and intestinal organoids to identify whether the ENS, via NDRG4, affects intestinal tumorigenesis. Linking immunostainings and gastrointestinal motility (GI) assays, we show that the absence of Ndrg4 does not trigger any functional or morphological GI abnormalities. However, combining in vivo, in vitro, and quantitative proteomics data, we uncover that Ndrg4 knockdown is associated with enlarged intestinal adenoma development and that organoid growth is boosted by the Ndrg4 ^−/− ENS cell secretome, which is enriched for Nidogen‐1 (Nid1) and Fibulin‐2 (Fbln2). Moreover, NID1 and FBLN2 are expressed in enteric neurons, enhance migration capacities of CRC cells, and are enriched in human CRC secretomes. Hence, we provide evidence that the ENS, via loss of Ndrg4, is involved in colorectal pathogenesis and that ENS‐derived Nidogen‐1 and Fibulin‐2 enhance colorectal carcinogenesis.     

The SARS‐unique domain (SUD) of SARS‐CoV and SARS‐CoV‐2 interacts with human Paip1 to enhance viral RNA translation

The ongoing outbreak of severe acute respiratory syndrome (SARS) coronavirus 2 (SARS‐CoV‐2) demonstrates the continuous threat of emerging coronaviruses (CoVs) to public health. SARS‐CoV‐2 and SARS‐CoV share an otherwise non‐conserved part of non‐structural protein 3 (Nsp3), therefore named as “SARS‐unique domain” (SUD). We previously found a yeast‐2‐hybrid screen interaction of the SARS‐CoV SUD with human poly(A)‐binding protein (PABP)‐interacting protein 1 (Paip1), a stimulator of protein translation. Here, we validate SARS‐CoV SUD:Paip1 interaction by size‐exclusion chromatography, split‐yellow fluorescent protein, and co‐immunoprecipitation assays, and confirm such interaction also between the corresponding domain of SARS‐CoV‐2 and Paip1. The three‐dimensional structure of the N‐terminal domain of SARS‐CoV SUD (“macrodomain II”, Mac2) in complex with the middle domain of Paip1, determined by X‐ray crystallography and small‐angle X‐ray scattering, provides insights into the structural determinants of the complex formation. In cellulo, SUD enhances synthesis of viral but not host proteins via binding to Paip1 in pBAC‐SARS‐CoV replicon‐transfected cells. We propose a possible mechanism for stimulation of viral translation by the SUD of SARS‐CoV and SARS‐CoV‐2.     

Nucleolar c‐Myc recruitment by a Vibrio T3SS effector promotes host cell proliferation and bacterial virulence

Pathogen type 3 secretion systems (T3SS) manipulate host cell pathways by directly delivering effector proteins into host cells. In Vibrio parahaemolyticus, the leading cause of bacterial seafood‐borne diarrheal disease, we showed that a T3SS effector, VgpA, localizes to the host cell nucleolus where it binds Epstein–Barr virus nuclear antigen 1‐binding protein 2 (EBP2). An amino acid substitution in VgpA (VgpA^L10A) did not alter its translocation to the nucleus but abolished the effector’s capacity to interact with EBP2. VgpA‐EBP2 interaction led to the re‐localization of c‐Myc to the nucleolus and increased cellular rRNA expression and proliferation of cultured cells. The VgpA‐EBP2 interaction elevated EBP2’s affinity for c‐Myc and prolonged the oncoprotein’s half‐life. Studies in infant rabbits demonstrated that VgpA is translocated into intestinal epithelial cells, where it interacts with EBP2 and leads to nucleolar re‐localization of c‐Myc. Moreover, the in vivo VgpA‐EBP2 interaction during infection led to proliferation of intestinal cells and heightened V. parahaemolyticus’ colonization and virulence. These observations suggest that direct effector stimulation of a c‐Myc controlled host cell growth program can contribute to pathogenesis.     

Infusion of hESC derived Immunity‐and‐matrix regulatory cells improves cognitive ability in early‐stage AD mice

ObjectivesIn this study, we administered immunity‐and‐matrix regulatory cells (IMRCs) via tail vein (IV) and intracerebroventricular (ICV) injection to 3‐month‐old 5×FAD transgenic mice to assess the effects of IMRC transplantation on the behaviour and pathology of early‐stage Alzheimer''s disease (AD).Materials and methodsClinical‐grade human embryonic stem cell (hESC)‐derived IMRCs were produced under good manufacturing practice (GMP) conditions. Three‐month‐old 5×FAD mice were administered IMRCs via IV and ICV injection. After 3 months, the mice were subjected to behavioural tests and electrophysiological analysis to evaluate their cognitive function, memory ability and synaptic plasticity. The effect of IMRCs on amyloid‐beta (Aβ)‐related pathology was detected by thioflavin‐S staining and Western blot. Quantitative real‐time PCR, ELISA and immunostaining were used to confirm that IMRCs inhibit neuroinflammation. RNA‐seq analysis was performed to measure changes in gene expression and perform a pathway analysis in response to IMRC treatment.ResultsIMRC administration via tail vein injection significantly ameliorated cognitive deficits in early‐stage AD (5×FAD) mice. However, no significant change was observed in the characteristic pathology of AD in the ICV group. Plaque analysis revealed that IMRCs did not influence either plaque deposition or BACE1 expression. In addition, IMRCs inhibited inflammatory responses and reduced microglial activation in vivo.ConclusionsWe have shown that peripheral administration of IMRCs can ameliorate AD pathology and associated cognitive deficits.     

Dietary cardenolides enhance growth and change the direction of the fecundity‐longevity trade‐off in milkweed bugs (Heteroptera: Lygaeinae)

Sequestration, that is, the accumulation of plant toxins into body tissues for defense, was predicted to incur physiological costs and may require resistance traits different from those of non‐sequestering insects. Alternatively, sequestering species could experience a cost in the absence of toxins due to selection on physiological homeostasis under permanent exposure of sequestered toxins in body tissues. Milkweed bugs (Heteroptera: Lygaeinae) sequester high amounts of plant‐derived cardenolides. Although being potent inhibitors of the ubiquitous animal enzyme Na⁺/K⁺‐ATPase, milkweed bugs can tolerate cardenolides by means of resistant Na⁺/K⁺‐ATPases. Both adaptations, resistance and sequestration, are ancestral traits of the Lygaeinae. Using four milkweed bug species (Heteroptera: Lygaeidae: Lygaeinae) and the related European firebug (Heteroptera: Pyrrhocoridae: Pyrrhocoris apterus) showing different combinations of the traits “cardenolide resistance” and “cardenolide sequestration,” we tested how the two traits affect larval growth upon exposure to dietary cardenolides in an artificial diet system. While cardenolides impaired the growth of P. apterus nymphs neither possessing a resistant Na⁺/K⁺‐ATPase nor sequestering cardenolides, growth was not affected in the non‐sequestering milkweed bug Arocatus longiceps, which possesses a resistant Na⁺/K⁺‐ATPase. Remarkably, cardenolides increased growth in the sequestering dietary specialists Caenocoris nerii and Oncopeltus fasciatus but not in the sequestering dietary generalist Spilostethus pandurus, which all possess a resistant Na⁺/K⁺‐ATPase. We furthermore assessed the effect of dietary cardenolides on additional life history parameters, including developmental speed, longevity of adults, and reproductive success in O. fasciatus. Unexpectedly, nymphs under cardenolide exposure developed substantially faster and lived longer as adults. However, fecundity of adults was reduced when maintained on cardenolide‐containing diet for their entire lifetime but not when adults were transferred to non‐toxic sunflower seeds. We speculate that the resistant Na⁺/K⁺‐ATPase of milkweed bugs is selected for working optimally in a “toxic environment,” that is, when sequestered cardenolides are stored in the body.     

20(S)‐Protopanaxadiol inhibits epithelial‐mesenchymal transition by promoting retinoid X receptor alpha in human colorectal carcinoma cells

Colorectal carcinoma (CRC) recurrence is often accompanied by metastasis. Most metastasis undergo through epithelial‐mesenchymal transition (EMT). Studies showed that retinol X receptor alpha (RXRα) and 20(S)‐Protopanaxadiol (PPD) have anti‐tumour effects. However, the anti‐metastasis effect of 20(S)‐PPD and the effect of RXRα on EMT‐induced metastasis are few studies on. Therefore, the role of RXRα and 20(S)‐PPD in CRC cell metastasis remains to be fully elucidated. RXRα with clinicopathological characteristics and EMT‐related expression in clinical samples were examined. Then, RXRα and EMT level in SW480 and SW620 cells, overexpressed and silenced RXRα in SW620 cells and SW480 cells, respectively, were evaluated. Finally, 20(S)‐PPD effect on SW620 and SW480 cells was evaluated. The results showed that a lower RXRα expression in cancer tissues, and a moderate negative correlation between RXRα and N stage, and tended to higher level of EMT. SW480 and SW620 cells had the highest and lowest RXRα expression among four CRC cell lines. SW480 had lower EMT level than SW620. Furthermore, 20(S)‐PPD increased RXRα and inhibited EMT level in SW620 cell. Finally, 20(S)‐PPD cannot restore SW480 cells EMT level to normal when RXRα silencing. These findings suggest that 20(S)‐PPD may inhibit EMT process in CRC cells by regulating RXRα expression.     

Dominant male song performance reflects current immune state in a cooperatively breeding songbird

Conspicuous displays are thought to have evolved as signals of individual “quality”, though precisely what they encode remains a focus of debate. While high quality signals may be produced by high quality individuals due to “good genes” or favourable early‐life conditions, whether current immune state also impacts signalling performance remains poorly understood, particularly in social species. Here, we experimentally demonstrate that male song performance is impaired by immune system activation in the cooperatively breeding white‐browed sparrow weaver (Plocepasser mahali). We experimentally activated the immune system of free‐living dominant males via subcutaneous injection of phytohemagglutinin (PHA) and contrasted its effects with those of a control (phosphate buffered saline) injection. PHA‐challenged males showed significant reductions in both the duration and the rate of their song performance, relative to controls, and this could not be readily attributed to effects of the challenge on body mass, as no such effects were detected. Furthermore, male song performance prior to immune‐challenge predicted the scale of the inflammatory response to the challenge. Our findings suggest that song performance characteristics are impacted by current immune state. This link between current state and signal performance might therefore contribute to enforcing the honesty of signal performance characteristics. Impacts of current state on signaling may be of particular importance in social species, where subordinates may benefit from an ability to identify and subsequently challenge same‐sex dominants in a weakened state.     

Dynamics of NK,CD8 and Tfh cell mediated the production of cytokines and antiviral antibodies in Chinese patients with moderate COVID‐19

Recent studies have demonstrated a marked decrease in peripheral lymphocyte levels in patients with coronavirus disease 2019 (COVID‐19) caused by severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2). Few studies have focused on the changes of NK, T‐ and B‐cell subsets, inflammatory cytokines and virus‐specific antibodies in patients with moderate COVID‐19. A total of 11 RT‐PCR‐confirmed convalescent patients with COVID‐19 and 11 patients with non‐SARS‐CoV‐2 pneumonia (control patients) were enrolled in this study. NK, CD8⁺ T, CD4⁺ T, Tfh‐like and B‐cell subsets were analysed using flow cytometry. Cytokines and SARS‐CoV‐2‐specific antibodies were analysed using an electrochemiluminescence immunoassay. NK cell counts were significantly higher in patients with COVID‐19 than in control patients (P = 0.017). Effector memory CD8⁺ T‐cell counts significantly increased in patients with COVID‐19 during a convalescent period of 1 week (P = 0.041). TIM‐3⁺ Tfh‐like cell and CD226⁺ Tfh‐like cell counts significantly increased (P = 0.027) and decreased (P = 0.022), respectively, during the same period. Moreover, ICOS⁺ Tfh‐like cell counts tended to decrease (P = 0.074). No abnormal increase in cytokine levels was observed. The high expression of NK cells is important in innate immune response against SARS‐CoV‐2. The increase in effector memory CD8⁺ T‐cell counts, the up‐regulation of inhibitory molecules and the down‐regulation of active molecules on CD4⁺ T cells and Tfh‐like cells in patients with COVID‐19 would benefit the maintenance of balanced cellular and humoural immune responses, may prevent the development of severe cases and contribute to the recovery of patients with COVID‐19.     

Solution structures of the Shewanella woodyi H‐NOX protein in the presence and absence of soluble guanylyl cyclase stimulator IWP‐051

Heme‐nitric oxide/oxygen binding (H‐NOX) domains bind gaseous ligands for signal transduction in organisms spanning prokaryotic and eukaryotic kingdoms. In the bioluminescent marine bacterium Shewanella woodyi (Sw), H‐NOX proteins regulate quorum sensing and biofilm formation. In higher animals, soluble guanylyl cyclase (sGC) binds nitric oxide with an H‐NOX domain to induce cyclase activity and regulate vascular tone, wound healing and memory formation. sGC also binds stimulator compounds targeting cardiovascular disease. The molecular details of stimulator binding to sGC remain obscure but involve a binding pocket near an interface between H‐NOX and coiled‐coil domains. Here, we report the full NMR structure for CO‐ligated Sw H‐NOX in the presence and absence of stimulator compound IWP‐051, and its backbone dynamics. Nonplanar heme geometry was retained using a semi‐empirical quantum potential energy approach. Although IWP‐051 binding is weak, a single binding conformation was found at the interface of the two H‐NOX subdomains, near but not overlapping with sites identified in sGC. Binding leads to rotation of the subdomains and closure of the binding pocket. Backbone dynamics are similar across both domains except for two helix‐connecting loops, which display increased dynamics that are further enhanced by compound binding. Structure‐based sequence analyses indicate high sequence diversity in the binding pocket, but the pocket itself appears conserved among H‐NOX proteins. The largest dynamical loop lies at the interface between Sw H‐NOX and its binding partner as well as in the interface with the coiled coil in sGC, suggesting a critical role for the loop in signal transduction.     

“Reframing” dopamine signaling at the intersection of glial networks in the aged Parkinsonian brain as innate Nrf2/Wnt driver: Therapeutical implications

Dopamine (DA) signaling via G protein‐coupled receptors is a multifunctional neurotransmitter and neuroendocrine–immune modulator. The DA nigrostriatal pathway, which controls the motor coordination, progressively degenerates in Parkinson''s disease (PD), a most common neurodegenerative disorder (ND) characterized by a selective, age‐dependent loss of substantia nigra pars compacta (SNpc) neurons, where DA itself is a primary source of oxidative stress and mitochondrial impairment, intersecting astrocyte and microglial inflammatory networks. Importantly, glia acts as a preferential neuroendocrine–immune DA target, in turn, counter‐modulating inflammatory processes. With a major focus on DA intersection within the astrocyte–microglial inflammatory network in PD vulnerability, we herein first summarize the characteristics of DA signaling systems, the propensity of DA neurons to oxidative stress, and glial inflammatory triggers dictating the vulnerability to PD. Reciprocally, DA modulation of astrocytes and microglial reactivity, coupled to the synergic impact of gene–environment interactions, then constitute a further level of control regulating midbrain DA neuron (mDAn) survival/death. Not surprisingly, within this circuitry, DA converges to modulate nuclear factor erythroid 2‐like 2 (Nrf2), the master regulator of cellular defense against oxidative stress and inflammation, and Wingless (Wnt)/β‐catenin signaling, a key pathway for mDAn neurogenesis, neuroprotection, and immunomodulation, adding to the already complex “signaling puzzle,” a novel actor in mDAn–glial regulatory machinery. Here, we propose an autoregulatory feedback system allowing DA to act as an endogenous Nrf2/Wnt innate modulator and trace the importance of DA receptor agonists applied to the clinic as immune modifiers.