[3H]Dopamine Uptake through the Dopamine and Norepinephrine Transporters is Decreased in the Prefrontal Cortex of Transgenic Mice Expressing HIV-1 Transactivator of Transcription Protein

AbstractHIV-1 transactivator of transcription (Tat) has a great impact on the development of HIV-1 associated neurocognitive disorders through disrupting dopamine transmission. This study determined the mutational effects of human dopamine transporter (hDAT) on basal and Tat-induced inhibition of dopamine transport. Compared to wild-type hDAT, the maximal velocity (Vmax) of [3H]dopamine uptake was decreased in D381L and Y88F/D206L/H547A, increased in D206L/H547A, and unaltered in D206L. Recombinant TatR1 − 86 inhibited dopamine uptake in wild-type hDAT, which was attenuated in either DAT mutants (D206L, D206L/H547A, and Y88F/D206L/H547A) or mutated TatR1 − 86 (K19A and C22G), demonstrating perturbed Tat-DAT interaction. Mutational effects of hDAT on the transporter conformation were evidenced by attenuation of zinc-induced increased [3H]WIN35,428 binding in D206L/H547A and Y88F/D206A/H547A and enhanced basal MPP+ efflux in D206L/H547A. H547A-induced outward-open transport conformational state was further validated by enhanced accessibility to MTSET ([2-(trimethylammonium)ethyl]-methanethiosulfonate) of an inserted cysteine (I159C) on a hDAT background.. Furthermore, H547A displayed an increase in palmitoylation inhibitor-induced inhibition of dopamine uptake relative to wide-type hDAT, indicating a change in basal palmitoylation in H547A. These results demonstrate that Y88F, D206L, and H547A attenuate Tat inhibition while preserving DA uptake, providing insights into identifying targets for improving DAT-mediated dopaminergic dysregulation. Graphical Abstract HIV-1 Tat inhibits dopamine uptake through human dopamine transporter (hDAT) on the presynaptic terminal through a direct allosteric interaction. Key hDAT residues D-H547, D-Y88, and D-D206 are predicted to be involved in the HIV-1 Tat-DAT binding. Mutating these residues attenuates this inhibitory effect by disrupting the Tat-hDAT interaction

Download Full-text

Region-specific effects of HIV-1 Tat on intrinsic electrophysiological properties of pyramidal neurons in mouse prefrontal cortex and hippocampus

Journal of Neurophysiology ◽

10.1152/jn.00029.2020 ◽

2020 ◽

Vol 123 (4) ◽

pp. 1332-1341 ◽

Cited By ~ 1

Author(s):

Thomas J. Cirino ◽

Scott W. Harden ◽

Jay P. McLaughlin ◽

Charles J. Frazier

Keyword(s):

Human Immunodeficiency Virus ◽

Prefrontal Cortex ◽

Pyramidal Neurons ◽

Intrinsic Excitability ◽

Tat Protein ◽

Electrophysiological Properties ◽

Specific Effects ◽

Immunodeficiency Virus ◽

Transactivator Of Transcription ◽

Hiv 1

Human immunodeficiency virus (HIV)-1 transactivator of transcription protein (Tat) is a viral protein that promotes transcription of the HIV genome and possesses cell-signaling properties. Long-term exposure of central nervous system (CNS) tissue to HIV-1 Tat is theorized to contribute to HIV-associated neurodegenerative disorder (HAND). In the current study, we sought to directly evaluate the effect of HIV-1 Tat expression on the intrinsic electrophysiological properties of pyramidal neurons located in layer 2/3 of the medial prefrontal cortex and in area CA1 of the hippocampus. Toward that end, we drove Tat expression with doxycycline (100 mg·kg−1·day−1 ip) in inducible Tat (iTat) transgenic mice for 7 days and then performed single-cell electrophysiological studies in acute tissue slices made through the prefrontal cortex and hippocampus. Control experiments were performed in doxycycline-treated G-tg mice, which retain the tetracycline-sensitive promoter but do not express Tat. Our results indicated that the predominant effects of HIV-1 Tat expression are excitatory in medial prefrontal cortical pyramidal neurons yet inhibitory in hippocampal pyramidal neurons. Notably, in these two populations, HIV-1 Tat expression produced differential effects on neuronal gain, membrane time constant, resting membrane potential, and rheobase. Similarly, we also observed distinct effects on action potential kinetics and afterhyperpolarization, as well as on the current-voltage relationship in subthreshold voltage ranges. Collectively, these data provide mechanistic evidence of complex and region-specific changes in neuronal physiology by which HIV-1 Tat protein may promote cognitive deficits associated with HAND. NEW & NOTEWORTHY We drove expression of human immunodeficiency virus (HIV)-1 transactivator of transcription protein (Tat) protein in inducible Tat (iTat) transgenic mice for 7 days and then examined the effects on the intrinsic electrophysiological properties of pyramidal neurons located in the medial prefrontal cortex (mPFC) and in the hippocampus. Our results reveal a variety of specific changes that promote increased intrinsic excitability of layer II/III mPFC pyramidal neurons and decreased intrinsic excitability of hippocampal CA1 pyramidal neurons, highlighting both cell type and region-specific effects.

Download Full-text

HIV-1 transgenic rats display an increase in [3H]dopamine uptake in the prefrontal cortex and striatum

Journal of NeuroVirology ◽

10.1007/s13365-015-0391-6 ◽

2015 ◽

Vol 22 (3) ◽

pp. 282-292 ◽

Cited By ~ 10

Author(s):

Jun Zhu ◽

Yaxia Yuan ◽

Narasimha M. Midde ◽

Adrian M. Gomez ◽

Wei-Lun Sun ◽

...

Keyword(s):

Prefrontal Cortex ◽

Dopamine Uptake ◽

Transgenic Rats ◽

Hiv 1

Download Full-text

Faculty Opinions recommendation of Priming HIV-1 broadly neutralizing antibody precursors in human Ig loci transgenic mice.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.726724591.793524291 ◽

2016 ◽

Author(s):

Noah Sather

Keyword(s):

Transgenic Mice ◽

Neutralizing Antibody ◽

Broadly Neutralizing Antibody ◽

Hiv 1

Download Full-text

A glycoside analog of mammalian oligomannose formulated with a TLR4-stimulating adjuvant elicits HIV-1 cross-reactive antibodies

Scientific Reports ◽

10.1038/s41598-021-84116-w ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Jean-François Bruxelle ◽

Tess Kirilenko ◽

Nino Trattnig ◽

Yiqiu Yang ◽

Matteo Cattin ◽

...

Keyword(s):

Transgenic Mice ◽

Envelope Protein ◽

Protein Sequence ◽

Neutralizing Antibodies ◽

Human Antibody ◽

Broadly Neutralizing Antibodies ◽

Specific Antibodies ◽

Strong Binding ◽

Hiv Envelope ◽

Hiv 1

AbstractThe occurrence of oligomannose-specific broadly neutralizing antibodies (bnAbs) has spurred efforts to develop immunogens that can elicit similar antibodies. Here, we report on the antigenicity and immunogenicity of a CRM197-conjugate of a previously reported oligomannose mimetic. Oligomannose-specific bnAbs that are less dependent on interactions with the HIV envelope protein sequence showed strong binding to the glycoconjugates, with affinities approximating those reported for their cognate epitope. The glycoconjugate is also recognized by inferred germline precursors of oligomannose-specific bnAbs, albeit with the expected low avidity, supporting its potential as an immunogen. Immunization of human-antibody transgenic mice revealed that only a TLR4-stimulating adjuvant formulation resulted in antibodies able to bind a panel of recombinant HIV trimers. These antibodies bound at relatively modest levels, possibly explaining their inability to neutralize HIV infectivity. Nevertheless, these findings contribute further to understanding conditions for eliciting HIV-cross-reactive oligomannose-specific antibodies and inform on next steps for improving on the elicited response.

Download Full-text

TAT-Conjugated NDUFS8 Can Be Transduced into Mitochondria in a Membrane-Potential-Independent Manner and Rescue Complex I Deficiency

International Journal of Molecular Sciences ◽

10.3390/ijms22126524 ◽

2021 ◽

Vol 22 (12) ◽

pp. 6524

Author(s):

Bo-Yu Lin ◽

Gui-Teng Zheng ◽

Kai-Wen Teng ◽

Juan-Yu Chang ◽

Chao-Chang Lee ◽

...

Keyword(s):

Membrane Potential ◽

Fusion Proteins ◽

Complex I ◽

Nadh Dehydrogenase ◽

Leigh Syndrome ◽

Protein Transduction ◽

Independent Manner ◽

Complex I Deficiency ◽

Transactivator Of Transcription ◽

Hiv 1

NADH dehydrogenase (ubiquinone) Fe-S protein 8 (NDUFS8) is a nuclear-encoded core subunit of human mitochondrial complex I. Defects in NDUFS8 are associated with Leigh syndrome and encephalomyopathy. Cell-penetrating peptide derived from the HIV-1 transactivator of transcription protein (TAT) has been successfully applied as a carrier to bring fusion proteins into cells without compromising the biological function of the cargoes. In this study, we developed a TAT-mediated protein transduction system to rescue complex I deficiency caused by NDUFS8 defects. Two fusion proteins (TAT-NDUFS8 and NDUFS8-TAT) were exogenously expressed and purified from Escherichia coli for transduction of human cells. In addition, similar constructs were generated and used in transfection studies for comparison. The results showed that both exogenous TAT-NDUFS8 and NDUFS8-TAT were delivered into mitochondria and correctly processed. Interestingly, the mitochondrial import of TAT-containing NDUFS8 was independent of mitochondrial membrane potential. Treatment with TAT-NDUFS8 not only significantly improved the assembly of complex I in an NDUFS8-deficient cell line, but also partially rescued complex I functions both in the in-gel activity assay and the oxygen consumption assay. Our current findings suggest the considerable potential of applying the TAT-mediated protein transduction system for treatment of complex I deficiency.

Download Full-text